Subjects -> EARTH SCIENCES (Total: 771 journals)
    - EARTH SCIENCES (527 journals)
    - GEOLOGY (94 journals)
    - GEOPHYSICS (33 journals)
    - HYDROLOGY (29 journals)
    - OCEANOGRAPHY (88 journals)

EARTH SCIENCES (527 journals)                  1 2 3 | Last

Showing 1 - 200 of 371 Journals sorted alphabetically
ACS Earth and Space Chemistry     Free   (Followers: 6)
Acta Brasiliensis     Open Access  
Acta Geochimica     Hybrid Journal   (Followers: 6)
Acta Geodaetica et Geophysica     Hybrid Journal   (Followers: 2)
Acta Geológica Lilloana     Open Access  
Acta Geophysica     Hybrid Journal   (Followers: 9)
Acta Geotechnica     Hybrid Journal   (Followers: 7)
Acta Meteorologica Sinica     Hybrid Journal   (Followers: 4)
Advances in High Energy Physics     Open Access   (Followers: 23)
Advances in Limnology     Full-text available via subscription   (Followers: 2)
Advances In Physics     Hybrid Journal   (Followers: 29)
Aeolian Research     Hybrid Journal   (Followers: 7)
African Journal of Aquatic Science     Hybrid Journal   (Followers: 17)
AGU Advances     Open Access   (Followers: 1)
Algological Studies     Full-text available via subscription   (Followers: 1)
All Earth     Open Access   (Followers: 3)
Alpine Botany     Hybrid Journal   (Followers: 4)
AMBIO     Hybrid Journal   (Followers: 12)
Anales del Instituto de la Patagonia     Open Access  
Andean geology     Open Access   (Followers: 10)
Annales Henri Poincaré     Hybrid Journal   (Followers: 2)
Annals of Geophysics     Open Access   (Followers: 12)
Annals of GIS     Open Access   (Followers: 31)
Annual Review of Marine Science     Full-text available via subscription   (Followers: 12)
Anthropocene     Hybrid Journal   (Followers: 6)
Anthropocene Review     Hybrid Journal   (Followers: 9)
Anuário do Instituto de Geociências     Open Access  
Applied Clay Science     Hybrid Journal   (Followers: 6)
Applied Computing and Geosciences     Open Access   (Followers: 3)
Applied Geochemistry     Hybrid Journal   (Followers: 14)
Applied Geomatics     Hybrid Journal   (Followers: 4)
Applied Geophysics     Hybrid Journal   (Followers: 12)
Applied Ocean Research     Hybrid Journal   (Followers: 7)
Applied Petrochemical Research     Open Access   (Followers: 2)
Aquatic Conservation Marine and Freshwater Ecosystems     Hybrid Journal   (Followers: 44)
Arctic Science     Open Access   (Followers: 7)
Arctic, Antarctic, and Alpine Research     Open Access   (Followers: 12)
arktos : The Journal of Arctic Geosciences     Hybrid Journal  
Artificial Intelligence in Geosciences     Open Access   (Followers: 6)
Artificial Satellites     Open Access   (Followers: 22)
Asia-Pacific Journal of Atmospheric Sciences     Hybrid Journal   (Followers: 21)
Asian Journal of Earth Sciences     Open Access   (Followers: 16)
Asian Journal of Physical and Chemical Sciences     Open Access   (Followers: 2)
Asian Review of Environmental and Earth Sciences     Open Access   (Followers: 1)
Atlantic Geology : Journal of the Atlantic Geoscience Society / Atlantic Geology : revue de la Société Géoscientifique de l'Atlantique     Open Access   (Followers: 10)
Atmosphere-Ocean     Full-text available via subscription   (Followers: 16)
Atmospheric and Climate Sciences     Open Access   (Followers: 31)
Australian Journal of Earth Sciences: An International Geoscience Journal of the Geological Society of Australia     Hybrid Journal   (Followers: 10)
Austrian Journal of Earth Sciences     Open Access   (Followers: 1)
AWWA Water Science     Hybrid Journal   (Followers: 1)
Bonorowo Wetlands     Open Access  
Boreas: An International Journal of Quaternary Research     Hybrid Journal   (Followers: 13)
Brill Research Perspectives in Map History     Full-text available via subscription   (Followers: 1)
Bulletin of Earthquake Engineering     Hybrid Journal   (Followers: 10)
Bulletin of Geosciences     Open Access   (Followers: 11)
Bulletin of the Lebedev Physics Institute     Hybrid Journal  
Bulletin of the Seismological Society of America     Full-text available via subscription   (Followers: 26)
Bulletin of Volcanology     Hybrid Journal   (Followers: 22)
Canadian Mineralogist     Full-text available via subscription   (Followers: 5)
Canadian Water Resources Journal     Hybrid Journal   (Followers: 18)
Carbonates and Evaporites     Hybrid Journal   (Followers: 1)
CATENA     Hybrid Journal   (Followers: 11)
Chemical Geology     Hybrid Journal   (Followers: 31)
Chinese Geographical Science     Hybrid Journal   (Followers: 6)
Ciencia del suelo     Open Access   (Followers: 1)
Ciencias Espaciales     Open Access  
Climate and Development     Hybrid Journal   (Followers: 33)
Coastal Management     Hybrid Journal   (Followers: 30)
Cogent Geoscience     Open Access  
Communications Earth & Environment     Open Access   (Followers: 2)
Comptes Rendus : Geoscience     Open Access   (Followers: 9)
Computational Geosciences     Hybrid Journal   (Followers: 17)
Computational Mathematics and Mathematical Physics     Hybrid Journal   (Followers: 5)
Computers and Geotechnics     Hybrid Journal   (Followers: 13)
Continental Shelf Research     Hybrid Journal   (Followers: 13)
Contributions to Mineralogy and Petrology     Hybrid Journal   (Followers: 11)
Contributions to Plasma Physics     Hybrid Journal   (Followers: 3)
Coral Reefs     Hybrid Journal   (Followers: 23)
Cretaceous Research     Hybrid Journal   (Followers: 10)
Depositional Record     Open Access  
Développement durable et territoires     Open Access   (Followers: 2)
Diatom Research     Hybrid Journal   (Followers: 3)
Doklady Physics     Hybrid Journal   (Followers: 1)
Dynamics of Atmospheres and Oceans     Hybrid Journal   (Followers: 19)
E&S Engineering and Science     Open Access  
E3S Web of Conferences     Open Access  
Earth and Planetary Physics     Open Access   (Followers: 2)
Earth and Planetary Science Letters     Hybrid Journal   (Followers: 149)
Earth and Space Science     Open Access   (Followers: 26)
Earth Interactions     Open Access   (Followers: 10)
Earth Science Malaysia     Open Access  
Earth Science Research     Open Access   (Followers: 9)
Earth Sciences Pakistan     Open Access  
Earth Sciences Research Journal     Open Access  
Earth Surface Dynamics (ESurf)     Open Access   (Followers: 10)
Earth Surface Dynamics Discussions (ESurfD)     Open Access   (Followers: 1)
Earth Surface Processes and Landforms     Hybrid Journal   (Followers: 25)
Earth System Dynamics     Open Access   (Followers: 6)
Earth System Dynamics Discussions     Open Access   (Followers: 3)
Earth Systems and Environment     Hybrid Journal   (Followers: 3)
Earth's Future     Open Access   (Followers: 6)
Earth, Planets and Space     Open Access   (Followers: 78)
Earthquake Engineering and Engineering Vibration     Hybrid Journal   (Followers: 8)
Earthquake Research Advances     Open Access   (Followers: 1)
Earthquake Spectra     Hybrid Journal   (Followers: 20)
Ecohydrology     Hybrid Journal   (Followers: 9)
Ecological Questions     Open Access   (Followers: 5)
Electromagnetics     Hybrid Journal   (Followers: 13)
Energy Efficiency     Hybrid Journal   (Followers: 10)
Energy Exploration & Exploitation     Open Access   (Followers: 4)
Energy Geoscience     Open Access   (Followers: 1)
Environmental Earth Sciences     Hybrid Journal   (Followers: 29)
Environmental Geology     Hybrid Journal   (Followers: 25)
Environmental Geosciences     Full-text available via subscription   (Followers: 6)
Environmental Geotechnics     Hybrid Journal   (Followers: 6)
Environmental Processes : An International Journal     Hybrid Journal  
Erwerbs-Obstbau     Hybrid Journal  
Estuaries and Coasts     Hybrid Journal   (Followers: 23)
Estuarine, Coastal and Shelf Science     Hybrid Journal   (Followers: 42)
Estudios Geográficos     Open Access   (Followers: 1)
European Journal of Mineralogy     Hybrid Journal   (Followers: 12)
European Journal of Remote Sensing     Open Access   (Followers: 18)
Exploration Geophysics     Hybrid Journal   (Followers: 4)
Facies     Hybrid Journal   (Followers: 9)
FIGEMPA : Investigación y Desarrollo     Open Access   (Followers: 1)
Física de la Tierra     Open Access  
Folia Musei rerum naturalium Bohemiae occidentalis. Geologica et Paleobiologica     Open Access  
Forestry Chronicle     Full-text available via subscription   (Followers: 9)
Frontiers in Earth Science     Open Access   (Followers: 8)
Frontiers in Soil Science     Open Access  
Frontiers of Earth Science     Hybrid Journal   (Followers: 12)
Fundamental and Applied Limnology / Archiv für Hydrobiologie     Full-text available via subscription   (Followers: 3)
GEM - International Journal on Geomathematics     Hybrid Journal   (Followers: 1)
Geo-Marine Letters     Hybrid Journal   (Followers: 6)
Geoacta     Open Access   (Followers: 2)
GeoArabia     Hybrid Journal  
Geobiology     Hybrid Journal   (Followers: 8)
Geocarto International     Hybrid Journal   (Followers: 23)
Geochemical Perspectives     Hybrid Journal   (Followers: 2)
Geochemistry     Hybrid Journal   (Followers: 5)
Geochemistry : Exploration, Environment, Analysis     Hybrid Journal   (Followers: 6)
Geochemistry, Geophysics, Geosystems     Full-text available via subscription   (Followers: 35)
Geochimica et Cosmochimica Acta     Hybrid Journal   (Followers: 54)
Geochronology (GChron)     Open Access  
Geochronometria     Open Access   (Followers: 1)
Geoderma Regional : The International Journal for Regional Soil Research     Full-text available via subscription   (Followers: 4)
Geodynamics & Tectonophysics     Open Access   (Followers: 3)
Geoenvironmental Disasters     Open Access   (Followers: 3)
Geofluids     Open Access   (Followers: 5)
Geoforum     Hybrid Journal   (Followers: 25)
Geography and Natural Resources     Hybrid Journal   (Followers: 8)
GeoHazards     Open Access   (Followers: 2)
GeoHealth     Open Access  
Geoheritage     Hybrid Journal   (Followers: 1)
Geoinformatics & Geostatistics     Hybrid Journal   (Followers: 14)
Geologia USP : Série Científica     Open Access   (Followers: 1)
Geological Journal     Hybrid Journal   (Followers: 19)
Geological Magazine     Hybrid Journal   (Followers: 16)
Geology Today     Hybrid Journal   (Followers: 31)
Geology, Geophysics and Environment     Open Access   (Followers: 2)
Geomagnetism and Aeronomy     Hybrid Journal   (Followers: 3)
Geomatics, Natural Hazards and Risk     Open Access   (Followers: 13)
Geomechanics and Geophysics for Geo-Energy and Geo-Resources     Hybrid Journal  
Geomechanics for Energy and the Environment     Full-text available via subscription  
GEOmedia     Open Access   (Followers: 1)
Geomorphology     Hybrid Journal   (Followers: 33)
Geophysical & Astrophysical Fluid Dynamics     Hybrid Journal   (Followers: 8)
Geophysical Journal International     Hybrid Journal   (Followers: 40)
Geophysical Prospecting     Hybrid Journal   (Followers: 7)
Geophysics     Full-text available via subscription   (Followers: 20)
Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards     Hybrid Journal   (Followers: 8)
Geoscience Canada : Journal of the Geological Association of Canada / Geoscience Canada : journal de l'Association Géologique du Canada     Full-text available via subscription   (Followers: 6)
Geoscience Communication     Open Access  
Geoscience Data Journal     Open Access   (Followers: 5)
Geoscience Frontiers     Open Access   (Followers: 10)
Geoscience Letters     Open Access  
Geosciences     Open Access   (Followers: 3)
Geosciences Journal     Hybrid Journal   (Followers: 10)
Geoscientific Instrumentation, Methods and Data Systems     Open Access   (Followers: 2)
Geoscientific Instrumentation, Methods and Data Systems Discussions     Open Access   (Followers: 1)
Geoscientific Model Development     Open Access   (Followers: 8)
Geoscientific Model Development Discussions     Open Access  
Geostandards and Geoanalytical Research     Hybrid Journal   (Followers: 3)
Geosystem Engineering     Hybrid Journal  
Geosystems and Geoenvironment     Open Access  
Geotectonic Research     Full-text available via subscription   (Followers: 5)
Geotectonics     Hybrid Journal   (Followers: 9)
Glass Physics and Chemistry     Hybrid Journal  
Global and Planetary Change     Hybrid Journal   (Followers: 18)
Global Biogeochemical Cycles     Full-text available via subscription   (Followers: 17)
Gondwana Research     Hybrid Journal   (Followers: 10)
GPS Solutions     Hybrid Journal   (Followers: 28)
Grassland Science     Hybrid Journal  
Ground Water Monitoring & Remediation     Hybrid Journal   (Followers: 25)
Groundwater     Hybrid Journal   (Followers: 37)
Groundwater for Sustainable Development     Full-text available via subscription   (Followers: 5)
Helgoland Marine Research     Open Access   (Followers: 2)
History of Geo- and Space Sciences     Open Access   (Followers: 1)
Hydrobiologia     Hybrid Journal   (Followers: 21)
Hydrogeology Journal     Hybrid Journal   (Followers: 21)

        1 2 3 | Last

Similar Journals
Journal Cover
Earthquake Spectra
Number of Followers: 20  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 8755-2930 - ISSN (Online) 1944-8201
Published by
  • Use of scenario earthquakes for seismic hazard assessment in
           low-seismicity, stable continental regions: A case study from Indiana, USA
           

    • Free pre-print version: Loading...

      Authors: Elizabeth M Sherrill, Michael W Hamburger, M Anna Nowicki Jessee
      Abstract: Earthquake Spectra, Ahead of Print.
      While large earthquakes have been documented in stable continental regions, such as the central United States, they occur too infrequently to provide reliable observations of earthquake-related impacts. Using the state of Indiana as a case study, we investigate the impacts of five deterministic scenarios—three occurring outside the borders of the state and two within the state. They include a M7.3 Wabash Valley event in southern Illinois, a M7.6 New Madrid event in southeastern Missouri, a M6.2 event in west central Ohio, a M6.2 event near Evansville, Indiana, and a M5.8 Indianapolis event. The locations and magnitudes are based on known fault locations and credible interpretations of the earthquake history in the region. We use a combination of the US Geological Survey’s ShakeMap and the Federal Emergency Management Agency’s (FEMA) Hazus software packages to assess earthquake-triggered ground shaking and its effects on the built environment. We also use the United States Geological Survey (USGS) Ground Failure estimation tool to examine the spatial distribution of anticipated earthquake-induced landslides and liquefaction. The five main deterministic scenario models indicate that moderate-sized urban earthquakes may represent a greater threat to a state like Indiana than a large-magnitude event from the New Madrid seismic zone. To better understand the influence of earthquake source parameters on impacts, we conducted a sensitivity analysis for earthquakes near Indianapolis and Evansville, where we reviewed losses due to differences in magnitude, depth, strike, and dip. Based on the model projections, magnitude and depth have first-order and relatively predictable influence on losses. The orientation and dip of the causative fault in relation to populated areas can alter economic losses for an event of the same magnitude by 13%–32%. Deterministic scenario analyses, such as those presented here, can potentially be of widespread utility for understanding earthquake impacts in the central United States and other low-seismicity, stable continental regions.
      Citation: Earthquake Spectra
      PubDate: 2022-06-16T01:08:46Z
      DOI: 10.1177/87552930221096700
       
  • Guided post-earthquake reconnaissance surveys considering resource
           constraints for regional damage inference

    • Free pre-print version: Loading...

      Authors: Mohamadreza Sheibani, Ge Ou
      Abstract: Earthquake Spectra, Ahead of Print.
      The extent of loss in a seismic hazard can be moderated with on-time allocation of funds and initiation of recovery tasks. Among various examinations conducted following the hazard, buildings damages are assessed as part of the reconnaissance survey to learn and document the impact of the earthquake on structures. The results of the survey are used in financial aid estimation, which is crucial for the community rapid recovery acts after the hazard. Due to the urgent need for this information, the amount of information gained per unit of time should be optimized. This article aims at answering the question of how to maximize the information gain in the presence of resource constraints by directing the efforts of a reconnaissance surveying team. A data-driven method is proposed that actively learns the patterns of damage and recommends the most informative buildings to be inspected while considering the resource limitations. The framework utilizes an efficient active learning method based on mutual information and developed for Gaussian process regression (GPR) to identify the information-rich cases. To assess the contribution of information gain and resource allocation in the overall outcome of the damage inference, two simulated earthquake testbeds are studied. It is shown that in a co-optimization approach, damage labels of the majority of buildings can be accurately predicted after 1 week of damage inspections.
      Citation: Earthquake Spectra
      PubDate: 2022-06-16T01:05:09Z
      DOI: 10.1177/87552930221101415
       
  • Behavioral responses to earthquake shaking: Video footage analysis of the
           2016 Kaikōura earthquake in Wellington, Aotearoa New Zealand

    • Free pre-print version: Loading...

      Authors: Lauren J Vinnell, Piata Inch, David M Johnston, Nick Horspool
      Abstract: Earthquake Spectra, Ahead of Print.
      Initiatives such as the ShakeOut earthquake drill (run nationally in Aotearoa New Zealand since 2012) are effective at teaching the protective actions “drop, cover, and hold” which can reduce the likelihood of injury during earthquakes. However, our understanding of human behavior during actual shaking is limited. Previous work has used retrospective self-reports to explore what actions people take during and immediately after an earthquake. While informative, such data is exposed to biases common in these types of methods. It is therefore important to complement the previous research with more objective data. This research builds on previously-developed methods of analyzing Closed Circuit Television (CCTV) footage to examine actions taken during the 2016 Kaikōura earthquake at Wellington International Airport, Aotearoa New Zealand. Only one of the 68 codable individuals was observed to undertake “drop, cover, and hold” as recommended in New Zealand, although a quarter took some kind of protective action (e.g. dropping or covering). The majority responded by standing, walking, looking around, or helping those near them. Because this earthquake had distinct P-wave and S-waves, we were able to examine changes in behavior caused by increases in shaking intensity. Among the 36 individuals who could be observed during the strong S-wave jolt, 27 changed their behavior; 11 changed from not protecting themselves to taking at least one protective action, and another 8 who were already undertaking at least one protective action took a further one or more steps to protect themselves. Among the 10 people observed to have an uncontrolled response to the sudden increase in shaking intensity, nine were taking no actions to protect themselves demonstrating the importance of taking protective actions before the arrival of strong shaking. This article presents key considerations for CCTV analysis and useful observations of behavior during earthquake shaking which can help to reduce injuries and fatalities.
      Citation: Earthquake Spectra
      PubDate: 2022-06-08T09:43:58Z
      DOI: 10.1177/87552930221086303
       
  • Site response of sedimentary basins and other geomorphic provinces in
           southern California

    • Free pre-print version: Loading...

      Authors: Chukwuebuka C Nweke, Jonathan P Stewart, Pengfei Wang, Scott J Brandenberg
      Abstract: Earthquake Spectra, Ahead of Print.
      Ergodic site amplification models for active tectonic regions are conditioned on the time-averaged shear wave velocity in the upper 30 m (VS30) and the depth to a shear wave velocity isosurface (zx). The depth components of such models are derived using data from sites within many geomorphic domains. We provide a site amplification model utilizing VS30 and depth, with the depth component conditioned on type of geomorphic province: basins, valleys, and mountain/hills. As with current models, the depth component of our model is centered with respect to the VS30-scaling model using differential depth δzx, taken as the difference between a site-specific depth and a VS30-conditioned average depth. Using data from southern California, we find that long-period site response for all sites combined exhibits relative de-amplification and amplification for negative and positive differential depths, respectively. Individual provinces exhibit broadly similar trends with depth, but amplification levels are on average stronger in basins such that little relative de-amplification occurs at negative differential depths. Valley and mountain/hill sites have, on average, weaker amplification levels but stronger scaling with δzx. Site-to-site standard deviations vary appreciably across geomorphic provinces, with basins having lower dispersions than mountain/hill sites and the reference ergodic model.
      Citation: Earthquake Spectra
      PubDate: 2022-05-31T02:06:22Z
      DOI: 10.1177/87552930221088609
       
  • GMPE-consistent hard-rock site adjustment factors for Western North
           America

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      Authors: Linda Al Atik, Nicholas J Gregor, Norman A Abrahamson, Albert R Kottke
      Abstract: Earthquake Spectra, Ahead of Print.
      Empirical ground-motion prediction equations (GMPEs) such as the Next Generation Attenuation-West2 (NGA-West2) GMPEs are limited in the number of recordings on hard-rock stations used to develop the models. Therefore, the site response scaling in the GMPEs cannot be reliably extrapolated to hard-rock conditions. The state of practice for the development of hard-rock adjustment factors involves the use of analytical methods that typically assign small values to the small-strain damping parameter ([math]) for hard-rock sites resulting in large scaling factors at short periods. Alternatively, the hard-rock scaling factors developed in Ktenidou and Abrahamson (KA16) based on empirical ground-motion data are used. These empirical factors, developed for a broad rock site category, show that the average hard-rock scaling factors observed in ground-motion data are small in amplitude contrary to the large factors typically obtained from analytical studies. The empirically derived KA16 factors also suffer from limitations due to the relatively small number of rock sites in the data set and do not distinguish between different hard-rock conditions. To address the shortcomings in the current state of practice, we present a methodology to develop linear site adjustment factors to adjust the NGA-West2 GMPEs from VS30 of 760 m/s to target hard-rock site conditions with VS30 ranging from 1000 to 2200 m/s. These factors are analytically derived using the inverse random vibration theory (IRVT) approach of Al Atik et al. but with inputs constrained using the empirical KA16 factors and normalized to the scaling of the NGA-West2 GMPEs for VS30 of 1000 m/s. The proposed factors merge the results of the NGA-West2 site response scaling for VS30 ≤ 1000 m/s with the KA16 hard-rock category factors to produce a site factor model that is a continuous function of VS30. The epistemic uncertainty of these factors is evaluated.
      Citation: Earthquake Spectra
      PubDate: 2022-05-17T05:11:35Z
      DOI: 10.1177/87552930221092467
       
  • Bayesian parameter estimation of duration-based variables used in
           post-earthquake building recovery modeling

    • Free pre-print version: Loading...

      Authors: Morolake Omoya, Henry Burton, Hiba Baroud
      Abstract: Earthquake Spectra, Ahead of Print.
      A Bayesian parameter estimation methodology for updating the distributions of the duration-based variables used in post-earthquake building recovery modeling is presented. The distributions of the recovery-related parameters specified in the resilience-based earthquake design initiative (REDi) and HAZUS are used as the basis of the priors. A data set of observed building damage and recovery following the 2014 South Napa earthquake is assembled and used to illustrate the proposed methodology. The recovery data set includes the permit acquisition and repair time for over 800 buildings affected by the earthquake. With this data, the conjugate prior (CP) and Markov Chain Monte Carlo (MCMC) methods are implemented to update the probability distribution parameters for the duration-based recovery variables. While the CP approach is easier to implement because it offers an analytical solution, the MCMC provides more flexibility in terms of the types of prior and sampling distributions that can be accommodated. Moreover, the results from a comparative implementation on the Napa data set shows that the MCMC method provides a reasonable approximation of the posterior marginal distribution of the duration-based recovery variables relative to the CP analytical solution.
      Citation: Earthquake Spectra
      PubDate: 2022-05-12T04:16:54Z
      DOI: 10.1177/87552930211073717
       
  • Site characterization at Treasure Island and Delaney Park downhole arrays
           by heterogeneous data assimilation

    • Free pre-print version: Loading...

      Authors: Elnaz Seylabi, Mohamad M Hallal, Brady R Cox
      Abstract: Earthquake Spectra, Ahead of Print.
      This article extends a recently proposed heterogeneous data assimilation technique for site characterization to estimate compression and shear wave velocity (Vp and Vs, respectively) and damping at Treasure Island and Delaney Park downhole arrays. The adopted method is based on the joint inversion of earthquake acceleration time series and experimental surface wave dispersion data and includes physical constraints to improve the inverse problem’s well-posedness. We first use synthetic data at these two sites to refine the proposed approach and then apply the refined algorithm to real datasets available at the Treasure Island and Delaney Park downhole arrays. The joint inversion results show that the estimated Vs and Vp profiles are in very good agreement with measured profiles at these two sites. Our synthetic and real data experiment results suggest that Vp estimation from inversion at downhole arrays can be improved by integrating the water table depth information or the higher modes of the Rayleigh wave dispersion data. In the last part of this article, we compare the performance of the inverted profiles to other methods used to incorporate spatial variability and wave scattering effects in one-dimensional (1D) ground response analysis (GRA). The comparisons show that the joint inversion-based Vs and Vp profiles and damping ratios estimated in this article can better integrate the effects of spatial variability and wave scattering into 1D GRAs, especially at the Delaney Park downhole array, which is classified as a poorly modeled site using traditional 1D GRA.
      Citation: Earthquake Spectra
      PubDate: 2022-05-10T06:51:07Z
      DOI: 10.1177/87552930221094060
       
  • Seismic risk assessment and mitigation analysis of large public school
           building portfolios in Metro Manila

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      Authors: Kevin Jeswani, Jack Guo, Constantin Christopoulos
      Abstract: Earthquake Spectra, Ahead of Print.
      This article presents an integrated framework for portfolio seismic risk assessment. The framework includes a systematic approach to the collection and categorization of exposed assets, and a robust method that combines vulnerabilities of different levels of resolution, including detailed vulnerabilities based on Federal Emergency Management Agency (FEMA) P-58 and REDi analyses, to produce efficient portfolio-level assessment. The vulnerability information encodes risk information that directly addresses the decision-support needs of stakeholders, including the benefits of seismic retrofit. The proposed framework is applied to a spatially distributed infrastructure portfolio composed of over 1000 public school buildings across Makati and Quezon City, in the Metro Manila region in Philippines, to demonstrate the value of portfolio-level seismic risk mitigation strategies. This study illustrates that the proposed regional seismic risk assessment approach can provide more reliable regional risk assessments in a computationally efficient manner and is able to quantify different risk contributors and identify cost-drivers that can be targeted for performance-based risk management of large portfolios.
      Citation: Earthquake Spectra
      PubDate: 2022-05-07T08:27:34Z
      DOI: 10.1177/87552930221086304
       
  • Development of NGA-Sub ground-motion prediction equation of 5%-damped
           pseudo-spectral acceleration based on database of subduction earthquakes
           in Japan

    • Free pre-print version: Loading...

      Authors: Hongjun Si, Saburoh Midorikawa, Tadahiro Kishida
      Abstract: Earthquake Spectra, Ahead of Print.
      We developed an empirical ground-motion model for subduction earthquakes in Japan. The model is based on the extensive, comprehensive subduction database for Japan by the Pacific Earthquake Engineering Research Center. The model predicts the RotD50 horizontal components of peak ground acceleration, peak ground velocity, and 5%-damped elastic pseudo-spectral acceleration ordinates in the selected periods ranging from 0.01 to 10 s. The model includes predictor variables considering tectonic setting (i.e. interplate and intraplate), the hypocentral depths, magnitude scaling, distance attenuation, shallow soil, and the basin responses. The magnitude scaling of interplate earthquakes is well constrained in Japan for different periods because the database includes the well-recorded large-magnitude events (i.e. the 2003 Tokachi-Oki and 2011 Tohoku earthquakes). The developed ground-motion prediction equation covers the subduction earthquakes that occurred in Japan for moment magnitudes ranging from 5.5 to 9.1 with closest distances to the fault of less than 300 km.
      Citation: Earthquake Spectra
      PubDate: 2022-05-05T04:41:39Z
      DOI: 10.1177/87552930221090326
       
  • Understanding the wider social and economic context of post-earthquake
           cordons: A comparative case study between Christchurch, Aotearoa (New
           Zealand) and L’Aquila, Italy

    • Free pre-print version: Loading...

      Authors: Shakti R Shrestha, Caroline HR Orchiston, Kenneth J Elwood, David M Johnston, Julia S Becker, Isabella Tomassi
      Abstract: Earthquake Spectra, Ahead of Print.
      Post-earthquake cordons have been used after seismic events around the world. However, there is limited understanding of cordons and how contextual information such as geography, sociocultural characteristics, economy, and institutional and governance structures affects decisions and operational procedures, including aspects related to spatial and temporal attributes of cordon establishment. This research aims to fill the gap in cordon knowledge through a qualitative comparative case study of two cities: Christchurch, New Zealand (Mw 6.2 earthquake, February 2011) and L’Aquila, Italy (Mw 6.3 earthquake, 2009). Both cities suffered comprehensive damage to their city centers and had cordons established for extended periods of time. Data collection was done through purposive and snowball sampling whereby 23 key informants were interviewed in total. Research participants held expert knowledge in their roles and responsibilities, that is, council members, emergency managers, politicians, business/insurance representatives, academics, and police. Results illustrate that cordons were primarily established to ensure safety of people and to maintain security. The extent and duration of the cordons were affected by the recovery approaches taken in respective cities, that is, in Christchurch demolition was widely undertaken which supported recovery and allowed for faster removal of cordons. In contrast, authorities in L’Aquila placed high value on heritage buildings which led to recovery strategy based on preserving and restoring most of the buildings which extended the duration of cordon. Extended cordons have many similarities but evolve overtime. This evolution of cordons is affected by site-specific needs; thus, cordons should be understood and planned based on contextual realities.
      Citation: Earthquake Spectra
      PubDate: 2022-04-21T01:21:52Z
      DOI: 10.1177/87552930221091593
       
  • Comprehensive numerical analyses of the seismic performance of natural gas
           pipelines crossing earthquake faults

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      Authors: Wenyang Zhang, Francois Ayello, Doug Honegger, Ertugrul Taciroglu, Yousef Bozorgnia
      Abstract: Earthquake Spectra, Ahead of Print.
      Coseismic fault displacement has been recognized as a critical hazard to natural gas transmission pipelines crossing earthquake faults. Prior studies on pipeline response to fault displacement were limited to specific types of pipes and faults, which were indeed constrained by the computational resources. As part of an effort to develop a Bayesian model to relate ground displacement in pipeline strain, we analyze more than 217,000 finite element models of gas pipeline fault crossings, which consider the pipe–soil interactions with both pipe and soil material nonlinearities. Such an enormous number of simulations are selected based on comprehensive sensitivity analyses and cover the most important parameters of gas pipelines in terms of combinations of the following: (1) pipe dimensions and materials, (2) soil properties, and (3) style of faulting and characteristics of fault movements. We devise an automated workflow for input generation–simulation submission–output extraction, by utilizing more than 10,000 cores high-performance super-computing facilities. Finally, we examine the pipeline response for every combination, by investigating the evolution of maximum compressive and tensile strains in the axial direction along the pipe over the fault displacement. These numerical analyses resulted in a comprehensive database of pipeline fragilities crossing earthquake fault for seismic risk analysis of natural gas infrastructure in an earthquake region.
      Citation: Earthquake Spectra
      PubDate: 2022-04-21T01:21:02Z
      DOI: 10.1177/87552930221087749
       
  • A comparative study of seismic analysis, design, and collapse safety
           margins of tall buildings in the United States and Japan: Part II:
           comparison of seismic capacity and collapse safety margin

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      Authors: Kristijan Kolozvari, Yusuke Hori, Hiroshi Yasumoto, Yoshitaka Suzuki, Masayoshi Nakashima, Farzad Naeim
      Abstract: Earthquake Spectra, Ahead of Print.
      This is an extension of the companion paper (Part 1) that presents the details of the two buildings located in Tokyo and designed using the US Performance Based Seismic Design (PBSD) methodology for one building (US Prototype Building) and the Japanese PBSD methodology for the other (Japan Prototype Building). The paper presents the IDA results and associated discussion on the collapse safety margin and the damage progress of the major structural elements. The Japan Prototype Building made of steel moment-resisting frames equipped with oil dampers is 1.5 times stronger in terms of the collapse safety margin than the US Prototype Building made of an reinforced concrete (RC) core shear wall system. The difference between the two buildings is believed to occur because of the larger redundancy and resultant larger over-strength achieved by the Japan Prototype Building. It is noteworthy that the construction cost of the Japan Prototype Building is about 30% higher than the US Prototype Building as indicated in Part 1. To explain the behavioral difference, sequences, and progresses of damage to major structural members are characterized in reference to the fragility curves of respective members. The benefits of oil dampers are found that the addition of the oil dampers would increase the collapse safety margin by 29% with an extra construction cost of 3%.
      Citation: Earthquake Spectra
      PubDate: 2022-04-21T01:19:18Z
      DOI: 10.1177/87552930221076534
       
  • Experimental testing on nonstructural continuous plasterboard suspended
           ceiling systems under shake table-generated motions

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      Authors: Venkatesh Patnana, Durgesh C Rai
      Abstract: Earthquake Spectra, Ahead of Print.
      Three different continuous plasterboard suspended ceiling systems were experimentally investigated through shake table-generated motions: (1) vertical strut ceiling system with all edges fixed, (2) vertical strut and lateral brace ceiling system with all edges free, and (3) vertical strut ceiling system with all edges free. Dynamic behavior and performance of these ceiling systems were evaluated to understand the effect of various boundary conditions and lateral force-resisting mechanisms at increasing intensity levels of input motion. All the ceiling systems performed well up to floor accelerations ranging from 1.4 to 1.6 g without any visible damage. However, under sinusoidal excitation at the natural frequency of the ceiling systems, the strut system with free boundaries proved vulnerable as it slipped from the perimeter channel leading to major damage. This suggests that the vertical strut system with free edges is vulnerable for multistory buildings located in any seismic zone due to its poor performance observed under large acceleration demands.
      Citation: Earthquake Spectra
      PubDate: 2022-04-20T09:12:50Z
      DOI: 10.1177/87552930221085298
       
  • Corrigendum

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      Abstract: Earthquake Spectra, Ahead of Print.

      Citation: Earthquake Spectra
      PubDate: 2022-04-13T09:42:54Z
      DOI: 10.1177/87552930221089393
       
  • Seismic performance of UHV composite post electrical equipment
           interconnected using a rigid bus with a sliding fitting

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      Authors: Chang He, Yue Zhang, Qiang Xie, Zhenyu Yang
      Abstract: Earthquake Spectra, Ahead of Print.
      To evaluate the influence of a rigid bus on the interconnected post electrical equipment with a sliding fitting, this article conducted shaking table tests on two full-scaled ±800 kV ultra-high voltage post insulators. Simplifying the rigid bus with a sliding fitting serving as a linear spring and damper allowed us to create a dynamic model of the stand-alone insulators and establish advanced two-piece interconnected post electrical equipment. Later, parametric analyses were carried out on the dynamic model. The results showed that the frequencies of the interconnected system were similar to those of the stand-alone counterparts if the dynamic characteristics of the two interconnected items were similar. The seismic responses of the interconnected system generally decrease compared with those of the stand-alone insulators. Thus, the seismic performance of the rigid bus interconnected electrical equipment system could qualify as having a stand-alone status if the dynamic characteristics of the equipment items are similar. The connection stiffness greatly affects the seismic responses of UHV composite post electrical equipment.
      Citation: Earthquake Spectra
      PubDate: 2022-04-08T12:56:59Z
      DOI: 10.1177/87552930221077123
       
  • Seismic gap between buildings founded on different soil types experiencing
           pounding during earthquakes

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      Authors: Mahmoud Miari, Robert Jankowski
      Abstract: Earthquake Spectra, Ahead of Print.
      Several formulas have been suggested in the literature to evaluate the minimum seismic gap that would prevent collisions between adjacent buildings during earthquakes, including those based on the absolute sum of the peak displacements (ABS), square root of the sum of the squares (SRSS), the double difference (DDC) method, Australian code, and approach proposed by Naderpour et al. The aim of the present study is to evaluate the influence of the seismic gap on the behavior of buildings experiencing pounding, as well as verify the accuracy of these five formulas for structures founded on different soil types. Three buildings (4-story, 6-story, and 8-story buildings) were considered and three pounding scenarios were modeled. In the first part of the study, these three pounding scenarios were analyzed by considering three different seismic gaps (1 mm, 1 cm, and 1 m). In the second part, the accuracy of the aforementioned formulas was verified for buildings founded on different soil types (hard rock, rock, very dense soil and soft rock, stiff soil, and soft clay soil). The results indicated that the seismic gap had a significant influence on the response of colliding buildings, including the peak story accelerations and pounding forces. Moreover, increasing the gap did not always lead to a reduction in the effects of pounding, unless it was large enough to eliminate structural collisions during earthquakes. In addition, all five formulas were found to provide poor estimates when considering different soil types. The ABS and the Naderpour et al. formulas were found to always be conservative, but they overestimated the minimum gap that would prevent pounding. Moreover, the DDC and Australian code formulas provided overestimate, accurate, and underestimate results, and the SRSS formula provided both accurate and overestimate results.
      Citation: Earthquake Spectra
      PubDate: 2022-04-07T12:37:32Z
      DOI: 10.1177/87552930221082968
       
  • Site-specific adjustment framework for incremental dynamic analysis
           (SAF-IDA)

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      Authors: Kuanshi Zhong, Reagan Chandramohan, Jack W Baker, Gregory G Deierlein
      Abstract: Earthquake Spectra, Ahead of Print.
      The widely used incremental dynamic analysis (IDA) offers attractive efficiencies to organize and conduct nonlinear dynamic structural analyses under earthquake ground motions. However, its use of a fixed ground motion set limits its ability to resolve ground motion characteristics that vary based on location and intensity. To overcome this limitation and utilize IDA in site-specific seismic risk analysis, a new method is proposed, called the site-specific adjustment framework for incremental dynamic analysis (SAF-IDA), which involves two modifications to conventional IDA. The first is a process to select input ground motions for the IDA over a distributed grid of ground motion characteristics that influence structural response. The second is a post-processing procedure to develop a surrogate model from the raw IDA data to adjust the structural response results based on site- and intensity-specific ground motion hazard parameters. The proposed SAF-IDA method is illustrated in case study analyses of archetype building structures and validated through comparison with analysis results based on more computationally intensive multiple stripe analysis (MSA), which employs site-specific selection of ground motions for each intensity level.
      Citation: Earthquake Spectra
      PubDate: 2022-03-31T11:33:47Z
      DOI: 10.1177/87552930221083688
       
  • Region-specific linear site amplification model for peaty organic soil
           sites in Hokkaido, Japan

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      Authors: Pengfei Wang, Yi Tyan Tsai, Jonathan P Stewart, Atsushi Mikami, Scott J Brandenberg
      Abstract: Earthquake Spectra, Ahead of Print.
      We develop a site amplification model for a regional geologic condition that includes surficial deposits of peaty organic soils in Hokkaido, Japan. We use ground motion data from national Japanese networks along with local data from the study region. We apply a non-reference site approach to infer site effects from misfits of reference ground motion models to data from 10 subduction zone earthquakes. Application of this approach requires removal of source-specific biases and careful consideration of source-to-site path effects. These considerations are essential to avoid mapping source- or path-related model misfits into estimates of site response. We consider three subduction ground motion models as reference models. By paying special attention to the conditions for which the path models are effective, and making adjustments for between-island path misfits (Hokkaido to Honshu and vice versa), we identify regional site effects that are insensitive to the ground motion models used in their derivation. Observed site responses are characterized by strong resonances at first-mode site frequencies, and as a result the regional model is conditioned on peak frequency from horizontal-to-vertical spectral ratios.
      Citation: Earthquake Spectra
      PubDate: 2022-03-25T05:27:13Z
      DOI: 10.1177/87552930221082965
       
  • Simplified solution for seismic earth pressures exerted on flexible walls

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      Authors: Maria Giovanna Durante, Jonathan P Stewart, Scott J Brandenberg, George Mylonakis
      Abstract: Earthquake Spectra, Ahead of Print.
      Seismic earth pressures acting on basement walls and retaining walls are most commonly computed using limit state methods, in which the effects of earthquake shaking are represented by a horizontal body force in an active soil wedge. Limit state methods provide a poor physical representation of the fundamental mechanisms that give rise to seismic earth pressures, which depend on relative wall–soil displacements. Such displacements are a consequence of soil–structure interaction, which, in the absence of a strong inertial component (e.g. from a connected structure), are mainly sensitive to the ratio of wavelength-to-wall height and relative wall-to-soil flexibility. We present a simplified single-frequency procedure for computing seismic earth pressures applied to flexible retaining structures by vertically propagating shear waves. The procedure accounts for the first-order wavelength and wall flexibility effects while simplifying a number of secondary effects in a manner that produces a slightly conservative outcome. Input parameters to the proposed solution are readily attainable for engineering design applications. For typical earth retention systems, earth pressures computed using the proposed procedure are lower than those computed using limit state solutions. Predictions from the proposed solution compare well with results of numerical simulations and centrifuge modeling from literature, whereas limit state procedures either do not provide a physically meaningful solution or produce strongly biased predictions (overprediction of experiments, underprediction of available simulations).
      Citation: Earthquake Spectra
      PubDate: 2022-03-24T04:00:52Z
      DOI: 10.1177/87552930221083326
       
  • A framework for operationalizing the assessment of post-earthquake
           functional recovery of buildings

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      Authors: Dustin T Cook, Abbie B Liel, Curt B Haselton, Maria Koliou
      Abstract: Earthquake Spectra, Ahead of Print.
      Building damage after an earthquake, or other hazard event, can interrupt businesses, displace households, and significantly disrupt a community for years. As a result, policymakers and engineers are working toward new design guidelines and policies that reduce the vulnerability of the built environment through improved building functional recovery performance. This study proposes a method for assessing post-earthquake building performance states of function and reoccupancy within the architecture of performance-based earthquake engineering, targeted at US construction, making use of Federal Emergency Management Agency (FEMA) P-58 fragility and consequence models. This is accomplished by mapping component damage states to systems-level operational performance, and then to building-level performance states, through a series of fault trees. The study also proposes a repair scheduling algorithm to estimate the time taken to restore building reoccupancy or function, considering impeding factors that delay the start of repairs. The result is a probabilistic approach that extends the performance-based engineering framework to explicitly quantify post-earthquake building function performance states, thus facilitating design and mitigation decisions for recovery-based performance objectives.
      Citation: Earthquake Spectra
      PubDate: 2022-03-24T03:59:15Z
      DOI: 10.1177/87552930221081538
       
  • A fragility-oriented approach for seismic retrofit design

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      Authors: Karim Aljawhari, Roberto Gentile, Carmine Galasso
      Abstract: Earthquake Spectra, Ahead of Print.
      This study proposes a practical fragility-oriented approach for the seismic retrofit design of case-study structures. This approach relies on mapping the increase of the global displacement-based ratio of capacity to life-safety demand (CDRLS) to the building-level fragility reduction. Specifically, the increase of CDRLS due to retrofitting is correlated with the corresponding shift in the fragility median values of multiple structure-specific damage states, observing that a pseudo-linear trend is appropriate under certain conditions. Accordingly, a practical approach is proposed to fit such a (structure-specific) linear trend and then use it by first specifying the desired fragility median and subsequently finding the corresponding target value of CDRLS that must be achieved through retrofit design. The validity of the proposed approach is illustrated for an archetype reinforced concrete (RC) structure not conforming to modern seismic design requirements, which has been retrofitted using various techniques, namely, fiber-reinforced polymers wrapping of columns and joints, RC jacketing, and steel jacketing.
      Citation: Earthquake Spectra
      PubDate: 2022-03-21T05:42:43Z
      DOI: 10.1177/87552930221078324
       
  • The Estimated Carbon Cost of Concrete Building Demolitions following the
           Canterbury Earthquake Sequence

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      Authors: Rosa E Gonzalez, Max T Stephens, Charlotte Toma, David Dowdell
      Abstract: Earthquake Spectra, Ahead of Print.
      The 2010/2011 Canterbury Earthquake Sequence caused severe economic impacts and community disruption in Christchurch, New Zealand due to damage from liquefaction and strong shaking. Following the earthquake, approximately 7500 dwellings and 1400 commercial properties were demolished, resulting in 4 million tons of building debris. Using the Canterbury event, and the subsequent building demolitions in Christchurch as a case study, this research quantifies the embodied carbon and energy costs associated with the post-earthquake demolition of buildings prior to the end of their intended design life. A building data set consisting of 142 reinforced concrete buildings that were demolished following the event was used to estimate the total amount of structural and non-structural debris resulting from the demolitions. A framework was developed to calculate the global warming potential of the demolished buildings considering embodied CO2 and energy in the building materials, impacts of the processes used in construction of the building, and CO2 emissions of the transport and waste management processes. A life cycle assessment tool was used to calculate the environmental costs in the production and transport module, the spatial distribution of the waste based on the building locations was calculated to determine transport distances to disposal facilities, and the waste disposal and recycling benefits were calculated using values from a life cycle inventory database. The results of the research revealed the demolition of concrete buildings had staggering environmental costs in terms of embodied CO2 and energy, which make the case for both resilient design strategies that reduce waste and pollution following earthquakes, and incorporating environmental impacts into demolition decisions.
      Citation: Earthquake Spectra
      PubDate: 2022-03-15T04:23:25Z
      DOI: 10.1177/87552930221082684
       
  • High-resolution post-earthquake recovery simulation: Impact of safety
           cordons

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      Authors: Anne M Hulsey, Jack W Baker, Gregory G Deierlein
      Abstract: Earthquake Spectra, Ahead of Print.
      A framework is proposed to assess the impact of safety cordons on the recovery of community functions after an earthquake, using high-resolution geospatial information to simulate the damage, cordons, and recovery trajectories for buildings in the affected area. Ground motion maps are developed to characterize shaking intensities for regional building-level engineering assessments of damage, repair times, and recovery times to quantify the impact of access restrictions associated with cordons around tall buildings with impaired collapse safety. The results are presented as recovery curves that quantify the cumulative loss in building functionality across the community as a function of time following an earthquake. A case study considers recovery of office space in Downtown San Francisco, following a Mw7.2 event on the San Andreas Fault. For this scenario, an average of 219 community days of office functionality are lost in the first year, representing about 60% of the total office space capacity. About one-third of the loss is attributed to access restrictions associated with cordons around older tall buildings. The proposed framework can be used to investigate the efficacy of various mitigation strategies to expedite recovery. While the most effective strategy for mitigating the overall impact of cordon restrictions is to seismically retrofit older tall buildings that trigger cordons, other less expensive preparedness measures are shown to be effective, depending on the recovery time frame of interest. Specifically, recovery preparedness measures are generally more effective when evaluated for longer-term recovery targets (e.g. recovery of function after 12 months) compared with short-term targets (e.g. recovery after 4 months).
      Citation: Earthquake Spectra
      PubDate: 2022-03-14T10:39:03Z
      DOI: 10.1177/87552930221075364
       
  • A comparative study of seismic analysis, design, and collapse safety
           margins of tall buildings in the United States and Japan, Part I:
           Performance-based analysis and design

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      Authors: Yusuke Hori, Yoshitaka Suzuki, Kristijan Kolozvari, Ola Johansson, Farzad Naeim, Masayoshi Nakashima
      Abstract: Earthquake Spectra, Ahead of Print.
      Performance-based seismic analysis and design of tall buildings have become increasingly common in the United States and have been the standard practice in Japan for a long time. The methodologies for seismic hazard analyses, selection of earthquake records for design, and acceptance criteria, however, are widely different in the two countries. Japan experiences large earthquakes and strong shakings of buildings significantly more frequently than the United States, and the data on actual seismic performance are richer in Japan than in the United States. Comparison of performance and calibration between the two design procedures can help to improve the quantitative assessment of seismic performance of buildings in the United States. This article presents the application of US and Japanese procedures to a tall building archetype once proportioned, analyzed, and designed according to US practices and once per Japanese practices. The structural systems selected are very different; for the United States, the archetype is designed using a core reinforced concrete shear wall building with composite floor systems and steel columns as the gravity system, whereas for Japan, the archetype is designed using a steel moment frame made of square concrete-filled steel tube (CFT) columns and composite beams and installed with oil dampers. Although the design procedures followed are vastly different, the seismic performances of the systems are rather similar during serviceability, design basis, and maximum considered events. As will be presented in the second part of this article, the collapse safety margins of the two designs are significantly different.
      Citation: Earthquake Spectra
      PubDate: 2022-03-14T05:20:03Z
      DOI: 10.1177/87552930221076528
       
  • Sensitivity of the conditional period selection in the structural response
           using the CMS as target spectrum

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      Authors: Carlos A Arteta, Andrés Torregroza, Daniel Gaspar, Norman Abrahamson
      Abstract: Earthquake Spectra, Ahead of Print.
      A framework is presented for assessing the sensitivity of typical engineering demand parameters (EDP) to the conditional period selection when using conditional mean spectra (CMS) as targets for ground-motion selection in a performance-based seismic evaluation. The framework consists of computing a suite of CMS targets anchored at conditioning periods within a period range of interest to discretize the demand at a given hazard level, as represented by a uniform hazard spectrum (UHS). Ground motions are selected and scaled for the CMS suite and the associated UHS. The envelope of the median responses from the CMS suite is compared with the median response from the UHS. The framework is instrumental in identifying the conditioning period (T*) range for estimating CMS to capture the maximum median responses at the hazard level of interest. It also helps to characterize the relative difference in responses between using CMS targets and a UHS. The implementation of the methodology is illustrated by evaluating response quantities such as displacement-, acceleration, and force-based EDPs of four reinforced concrete moment frame structures of different heights under three levels of increasing hazard. Results confirm that the conditioning period used for ground-motion selection has a significant impact on the seismic response of displacement-based EDPs, and the sensitivity of the response varies with building height. For other EDPs, like maximum base shear and story acceleration, the results vary. Based on a limited-size ground motion set typically used in practice, the results indicate that UHS-targeted ground motions do not necessarily yield greater demand in comparison with using the CMS for estimating peak story drifts. For maximum floor accelerations, however, the CMS did produce smaller responses.
      Citation: Earthquake Spectra
      PubDate: 2022-03-12T05:02:07Z
      DOI: 10.1177/87552930221081150
       
  • Characterizing uncertainty of general building stock exposure data

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      Authors: Charles K Huyck, Zhenghui “Z” Hu, Michael Eguchi, Georgiana Esquivias, Paul Amyx, Kay Smith, Colm Jordan
      Abstract: Earthquake Spectra, Ahead of Print.
      Effective disaster risk management (DRM) and disaster risk reduction (DRR) require modeling potential and post-event impacts using building exposure data. The data used to develop building exposure databases will influence the accuracy of risk assessments and the appropriateness of subsequent decisions. This article proposes a framework for classifying approaches of developing building exposure databases into levels. To examine the uncertainty introduced through using various approaches to exposure development, a probabilistic seismic risk assessment was run with the exposure data corresponding to each proposed level using the County of Los Angeles as the study area. A factor of ∼2.5 was observed in the final loss estimates. The variance was less dependent on the spatial scale of data than on key values, most notably estimates of building size and replacement cost.
      Citation: Earthquake Spectra
      PubDate: 2022-03-10T05:58:44Z
      DOI: 10.1177/87552930221079852
       
  • Shear-wave velocity map for Pohang Basin, South Korea, based on the P-wave
           seismogram method

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      Authors: Junyoung Lee, Kwang-Hee Kim, Su Young Kang, Moon Son, Byungmin Kim
      Abstract: Earthquake Spectra, Ahead of Print.
      The 2017 ML 5.4 Pohang, South Korea earthquake, which caused severe damage, raised attention to the importance of the characterization of the Pohang Basin structure and the identification of active faults. We utilize 366 seismograms recorded at 102 densely deployed seismic stations during 18 microearthquakes with ML ranging from −1.11 to 1.70. We perform the P-wave seismogram method, which has been validated in various regions using seismograms for moderate earthquakes, to estimate the time-averaged shear-wave velocity from the surface to a depth of 30 m (VS30) in and around the basin. We perform multichannel analyses of surface waves at the 32 sites to obtain shear-wave velocity (VS) profiles, and additionally acquire the 22 existing VS profiles within the study area. We observe that velocity seismograms predict VS30 more accurately than acceleration and displacement seismograms do. The estimated VS30 values are in good agreement with the measured VS30 values. Approximately 93.3% of the measured and estimated VS30 values are located between the ±100% difference lines. We propose a VS30 map for the vicinity of the Pohang Basin by geospatially interpolating both the measured and estimated VS30 values, which is consistent with the local topography and geology. The proposed map exhibits areas with strong VS30 contrast within the Quaternary and Tertiary sediments, which might be attributed to the existence of faults.
      Citation: Earthquake Spectra
      PubDate: 2022-02-26T04:48:53Z
      DOI: 10.1177/87552930221076532
       
  • Investment planning for earthquake-resilient electric power systems
           considering cascading outages

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      Authors: Boyu Cheng, Linda Nozick, Ian Dobson
      Abstract: Earthquake Spectra, Ahead of Print.
      Earthquakes cause outages of power transmission system components due to direct physical damage and also through the initiation of cascading processes. This article explores what are the optimal capacity investments to increase the resilience of electric power transmission systems to earthquakes and how those investments change with respect to two issues: (1) the impact of including cascades in the investment optimization model and (2) the impact of focusing more heavily on the early stages of the outages after the earthquake in contrast to more evenly focusing on outages across the entire restoration process. A cascading outage model driven by the statistics of sample utility data is developed and used to locate the cascading lines. We compare the investment plans with and without the modeling of the cascades and with different levels of importance attached to outages that occur during different periods of the restoration process. Using a case study of the Eastern Interconnect transmission grid, where the seismic hazard stems mostly from the New Madrid Seismic Zone, we find that the cascades have little effect on the optimal set of capacity enhancement investments. However, the cascades do have a significant impact on the early stages of the restoration process. Also, the cascading lines can be far away from the initial physically damaged lines. More broadly, the early stages of the earthquake restoration process is affected by the extent of the cascading outages and is critical for search and rescue as well as restoring vital services. Also, we show that an investment plan focusing more heavily on outages in the first 3 days after the earthquake yields fewer outages in the first month, but more outages later in comparison with an investment plan focusing uniformly on outages over an entire 6-month restoration process.
      Citation: Earthquake Spectra
      PubDate: 2022-02-24T04:34:29Z
      DOI: 10.1177/87552930221076870
       
  • New conditional, scenario-based, and traditional peak ground velocity
           models for interface and intraslab subduction zone earthquakes

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      Authors: Chenying Liu, Jorge Macedo
      Abstract: Earthquake Spectra, Ahead of Print.
      The Pacific Earthquake Engineering Research (PEER) Center next-generation attenuation relationships for subduction zone earthquakes (NGA-Sub) ground motion database is used to develop new conditional ground motion models (CGMMs), several scenario-based ground motion models (GMMs), and a traditional GMM to estimate the peak ground velocity (PGV) for subduction zone (interface, intraslab) earthquakes. The PGV estimate in the CGMMs is conditioned on the rupture distance (Rrup), magnitude (Mw), time-averaged shear wave velocity in the top 30 m (Vs30) and pseudo-spectral acceleration PSA(TPGV). The period TPGV in the CGMMs is magnitude dependent to account for the magnitude dependence of the earthquake source corner frequency in the Fourier amplitude spectrum. Several scenario-based models are developed by combining the CGMM with PSA GMMs to directly estimate PGV given an earthquake scenario and site condition. Scenario-based models capture the complex ground motion effects in the underlying PSA GMMs and ensure the consistency with a design PSA spectrum, which is desired in engineering practice. In addition, a traditional PGV GMM is developed using Bayesian hierarchical regression. Finally, we compare all of these models and find that the scenario-based models are consistent with the traditional model developed in this study giving confidence to their use. The conditional and traditional PGV GMMs developed in this study benefit the performance-based design of engineering systems affected by subduction earthquakes when PGV is an important intensity measure.
      Citation: Earthquake Spectra
      PubDate: 2022-02-18T04:55:04Z
      DOI: 10.1177/87552930211067817
       
  • Influence of earthquake damage and repair interventions on expected annual
           losses of reinforced concrete wall buildings

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      Authors: Alberto Rossi, Ciro Del Vecchio, Stefano Pampanin
      Abstract: Earthquake Spectra, Ahead of Print.
      Recent devastating earthquakes have shown that existing reinforced concrete (RC) buildings that rely on shear walls may exhibit damage and cracking. The majority of seismic actions are borne by shear walls; hence, the quantification of their residual post-earthquake capacity is critical. Moreover, the repair interventions that are typically implemented in practice may be insufficient to fully restore the original capacity of the undamaged system, particularly in terms of stiffness. This makes it difficult for stakeholders to decide on implementing either building repair or demolition and reconstruction. This article proposes a novel methodology to aid practitioners in quantifying the effect of earthquake damage and repair on the seismic performance of buildings with shear walls within a loss-assessment framework. A refined procedure relying on a validated nonlinear finite element numerical model capable of reproducing the shear response of RC walls is proposed along with an analytical approach. Parametric analyses of an RC case-study building are conducted, and the results are discussed and compared in terms of expected annual losses in the undamaged, damaged, and repaired configurations.
      Citation: Earthquake Spectra
      PubDate: 2022-02-17T10:19:03Z
      DOI: 10.1177/87552930211072878
       
  • Validating predicted site response in sedimentary basins from 3D ground
           motion simulations

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      Authors: Chukwuebuka C Nweke, Jonathan P Stewart, Robert W Graves, Christine A Goulet, Scott J Brandenberg
      Abstract: Earthquake Spectra, Ahead of Print.
      We introduce procedures to validate site response in sedimentary basins as predicted using ground motion simulations. These procedures aim to isolate contributions of site response to computed intensity measures relative to those from seismic source and path effects. In one of the validation procedures, simulated motions are analyzed in the same manner as earthquake recordings to derive non-ergodic site terms. This procedure compares the scaling with sediment isosurface depth of simulated versus empirical site terms (the latter having been derived in a separate study). A second validation procedure utilizes two sets of simulations, one that considers three-dimensional (3D) basin structure and a second that utilizes a one-dimensional (1D) representation of the crustal structure. Identical sources are used in both procedures, and after correcting for variable path effects, differences in ground motions are used to estimate site amplification in 3D basins. Such site responses are compared to those derived empirically to validate both the absolute levels and the depth scaling of site response from 3D simulations. We apply both procedures to southern California in a manner that is consistent between the simulated and empirical data (i.e. by using similar event locations and magnitudes). The results show that the 3D simulations overpredict the depth-scaling and absolute levels of site amplification in basins. However, overall patterns of site amplification with depth are similar, suggesting that future calibration may be able to remove observed biases.
      Citation: Earthquake Spectra
      PubDate: 2022-02-16T05:51:17Z
      DOI: 10.1177/87552930211073159
       
  • Discussion of Post-earthquake fast damage assessment using residual
           displacement and seismic energy: Application to Mexico City

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      Authors: Jorge Ruiz-García, Eduardo Miranda
      Abstract: Earthquake Spectra, Ahead of Print.
      A discussion on the article by Quinde et al. is presented. The methodology introduced by the authors is based on residual displacements computed from the inelastic response of elastoplastic single-degree-of-freedom systems subjected to synthetic ground motions representative of those recorded at soft soil sites in Mexico City. While the subject to the article is pertinent for post-earthquake assessment, this discussion points out and clarifies several issues about residual displacement demands and their estimation based on previously published investigations by the discussers.
      Citation: Earthquake Spectra
      PubDate: 2022-02-16T04:44:37Z
      DOI: 10.1177/87552930211068862
       
  • Generation of numerical-based capacity fragility curves for different
           aspect ratios of full-connection gypsum partition walls

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      Authors: Hamidreza Salmasi Javid, Masoud Mohammadgholiha, Siavash Soroushian, Esmaeel Rahmanishamsi, Emmanuel “Manos” Maragakis
      Abstract: Earthquake Spectra, Ahead of Print.
      Fragility curves for steel-framed partition walls in current guidelines (such as FEMA P-58) are mainly based on experimental studies with limited number of geometries. In light of extensive efforts made in the past decade on numerical simulation of these walls, combined experimental–numerical fragility curves can facilitate more reliable results. A previously validated modeling approach along with verified numerical-based fragility development methodology utilized to derive fragility curve for walls with aspects ratios ranging from 0.33 to 3 using OpenSees platform. Moreover, variation of maximum and median wall strengths as well as median fragility values were compared against different wall aspect ratios. Results of this article indicated that the maximum unit-length strength of full-connection partition walls fluctuates between 3.5 and 4.9 kN (0.25–0.34 kips). Also, vulnerability of partition walls increases when aspect ratio of walls decreases.
      Citation: Earthquake Spectra
      PubDate: 2022-02-16T04:42:56Z
      DOI: 10.1177/87552930211067267
       
  • Risk-based bridge component importance measures under seismic loads

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      Authors: Navya Vishnu, Jamie E Padgett, Leonardo Dueñas-Osorio
      Abstract: Earthquake Spectra, Ahead of Print.
      This article formulates risk-based component importance measures (RCIMs) to identify critical components for a bridge subjected to earthquakes. RCIM, unlike traditional reliability-based importance measures, is well suited for complex systems like bridges as it uses a flexible system failure definition using bridge level risk consequences or performance objectives. Contrasting traditional notions of risk and reliability related to structural system failures, the RCIMs embrace a broader definition of risk which includes consequences of system failure to society and the environment. System failure is defined as exceedance of a user-defined threshold of system risk (e.g. based on cost, emissions, embodied energy, or other metrics). Our definition of system failure using global performance metrics helps relating component to system reliability explicitly and offers an alternative perspective to aggregate joint failure events of bridge components into relevant damage states. RCIM combines information about the reliability of a component and its contribution to the system performance and hence the importance measures developed offer risk mitigation indicators for decision makers as to which components may require upgrade to achieve a given performance objective. The proposed RCIMs generalize existing importance measures through analytical exploration of the entire space of system configurations with correlated component failures, while also considering multiple risk-based criteria beyond reliability. These RCIMs, demonstrated through a seismic bridge system case study, further show that as the bridge components age and the hazard intensity varies, the relative contribution of the components to system risk also shifts.
      Citation: Earthquake Spectra
      PubDate: 2022-02-10T05:06:10Z
      DOI: 10.1177/87552930211073815
       
  • A framework for the rapid assessment of seismic upgrade viability using
           performance-based earthquake engineering

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      Authors: Paul Steneker, Lydell Wiebe, Andre Filiatrault, Dimitrios Konstantinidis
      Abstract: Earthquake Spectra, Ahead of Print.
      The performance-based earthquake engineering (PBEE) methodology allows designers to deaggregate expected seismic losses in a building to a component level. This deaggregated information provides the opportunity to tailor upgrade strategies to individual structures based on sources of losses. However, the optimization of an upgrade strategy becomes difficult because of the relationship between a structure and its nonstructural components; hence, multiple competing upgrade options must be considered. To address this obstacle, this article proposes a framework to guide the assessment of the viability of both structural and nonstructural upgrade strategies, while accounting for limited design resources likely encountered in the early stages of the design process. The framework utilizes the median shift probability (MSP) method, a modified version of the PBEE method introduced in this article, to rapidly summarize the effects of structural upgrades on nonstructural components by considering the impacts of structural modifications on the floor hazards. While accounting for this relationship, the MSP method utilizes the deaggregation of loss across different source categories to identify the benefit of combined structural and nonstructural upgrades, increasing a designer’s understanding of the impact of structural upgrades on losses and allowing for the rapid determination of optimized upgrade strategies unique to the owner’s conditions. A case study example of the implementation of the framework is provided, and the results obtained from the MSP method are compared with those obtained from more rigorous but resource-intensive optimization analysis. An implementation of the MSP method in Microsoft Excel is provided with this article.
      Citation: Earthquake Spectra
      PubDate: 2022-02-05T07:08:31Z
      DOI: 10.1177/87552930211065771
       
  • Chilean liquefaction case history database

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      Authors: Gonzalo Montalva, Francisco Ruz, Daniella Escribano, Nicolás Bastías, Daniela Espinoza, Felipe Paredes
      Abstract: Earthquake Spectra, Ahead of Print.
      This article describes a liquefaction database that contains a summary of 209 liquefaction, non-liquefaction, and marginal case histories compiled from the 2010 Mw 8.8 Maule, 2014 Mw 8.2 Iquique, 2015 Mw 8.3 Illapel, and 2016 Mw 7.6 Melinka earthquakes, where the liquefaction phenomenon caused damage to buildings, bridges, roads, and drainage systems, generating millions in losses at the infrastructure level. The database structure is organized into nine main tables that contain site information, geotechnical tests, and seismic parameters. The main tables include the locations of the sites, surface evidence of liquefaction or absence of them, geotechnical parameters from boreholes, and geophysical and laboratory tests. The database contains 7977 m of standard penetration test logs and 390 m of cone penetration test soundings from 209 sites explored. In addition, the seismic parameters of these earthquakes include ground-motion intensity measures estimated for each site. The information in this database allows a better characterization of the seismic demand and the geotechnical properties of the soil involved in predicting liquefaction triggering in this subduction zone. The data associated with this article are available in DesignSafe, where users can freely download and process data to train or evaluate predictive liquefaction models.
      Citation: Earthquake Spectra
      PubDate: 2022-01-27T08:38:34Z
      DOI: 10.1177/87552930211070313
       
  • Conducting 1D site response analyses to capture 2D VS spatial variability
           effects

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      Authors: Renmin Pretell, Katerina Ziotopoulou, Norman A Abrahamson
      Abstract: Earthquake Spectra, Ahead of Print.
      One-dimensional site response analyses (1D SRAs) with shear-wave velocity (VS) randomization are commonly performed to estimate median site-specific amplification factors (AFs) under the implicit assumption that this approach yields a realistic response. In this work, an investigation is conducted to determine the appropriate amount of VS randomization (σlnVs) needed to capture a median response that accounts for 2D VS spatial variability effects. Results from 2D SRAs and 1D SRAs with VS randomization show that the median 2D seismic responses are generally higher than 1D responses at the site’s fundamental frequency, and that higher VS variability has a mild impact on the median 2D seismic response amplitude at the fundamental frequency, whereas it significantly reduces the median 1D response. Findings indicate that the 84th percentile AFs based on 1D SRAs conducted with VS randomization using σlnVs = 0.25, approximate well with the more realistic median 2D SRA-based AFs around the fundamental frequency, while the 70th to 60th percentiles might be more appropriate at higher frequencies. The benefit of using percentiles of the 1D SRA-based AFs higher than the median is shown for different site conditions and supported by comparisons against empirical data from four downhole sites.
      Citation: Earthquake Spectra
      PubDate: 2022-01-27T08:35:52Z
      DOI: 10.1177/87552930211069400
       
  • RESPONSE TO Discussion by J. Ruiz-García and E. Miranda on
           “Post-earthquake fast damage assessment using residual displacement and
           seismic energy: Application to Mexico City”

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      Authors: Pablo Quinde, Amador Terán-Gilmore, Eduardo Reinoso
      Abstract: Earthquake Spectra, Ahead of Print.

      Citation: Earthquake Spectra
      PubDate: 2022-01-27T07:34:04Z
      DOI: 10.1177/87552930211068864
       
  • NGA-Sub source and path database

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      Authors: Victor Contreras, Jonathan P Stewart, Tadahiro Kishida, Robert B Darragh, Brian SJ Chiou, Silvia Mazzoni, Robert R Youngs, Nicolas M Kuehn, Sean K Ahdi, Katie Wooddell, Rubén Boroschek, Fabián Rojas, Jennyfer Órdenes
      First page: 799
      Abstract: Earthquake Spectra, Ahead of Print.
      We describe source and path attributes of the Next Generation of Ground-Motion Attenuation for Subduction zones (NGA-Sub) project relational database. The database contains 991 earthquakes between 1937 and 2016 that meet quality assurance standards and have assigned event types (mostly interface or intraslab). Data curation emphasized large magnitudes: 73% of events have M > 5 and 13 events have M > 8. Event attributes in the database can be broadly divided into those related to the moment tensor, those related to rupture surface geometry (referred to as finite-fault parameters), and categorizations by type (e.g. interface, intraslab) and sequence classification (mainshock, aftershock). Earthquake information and moment tensor parameters compiled from earthquake catalogs include event date and origin time, hypocenter location, seismic moment, and the strike, dip, and rake angles of nodal planes. Finite-fault parameters include along-strike length, down-dip width, and depth to top-of-rupture for one or more rectangles used to parameterize rupture surface geometry. These are modified from models in literature where available, and otherwise are simulated using procedures customized for subduction earthquakes. Rupture distance and other metrics are computed using finite-fault representations of sources, and (as applicable) are partitioned into forearc and backarc components. Forearc and backarc regions are defined based on volcano locations, and are assigned to events and sites.
      Citation: Earthquake Spectra
      PubDate: 2022-01-17T05:07:47Z
      DOI: 10.1177/87552930211065054
       
  • Host-region parameters for an adjustable model for crustal earthquakes to
           facilitate the implementation of the backbone approach to building
           ground-motion logic trees in probabilistic seismic hazard analysis

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      Authors: Peter J Stafford, David M Boore, Robert R Youngs, Julian J Bommer
      First page: 917
      Abstract: Earthquake Spectra, Ahead of Print.
      The backbone approach to constructing a ground-motion logic tree for probabilistic seismic hazard analysis (PSHA) can address shortcomings in the traditional approach of populating the branches with multiple existing, or potentially modified, ground-motion models (GMMs) by rendering more transparent the relationship between branch weights and the resulting distribution of predicted accelerations. To capture epistemic uncertainty in a tractable manner, there are benefits in building the logic tree through the application of successive adjustments for differences in source, path, and site characteristics between the host region of the selected backbone GMM and the target region for which the PSHA is being conducted. The implementation of this approach is facilitated by selecting a backbone GMM that is amenable to such host-to-target adjustments for individual source, path, and site characteristics. The NGA-West2 GMM of Chiou and Youngs (CY14) has been identified as a highly adaptable model for crustal seismicity that is well suited to such adjustments. Rather than using generic source, path, and site characteristics assumed appropriate for the host region, the final suite of adjusted GMMs for the target region will be better constrained if the host-region parameters are defined specifically on the basis of their compatibility with the CY14 backbone GMM. To this end, making use of a recently developed crustal shear-wave velocity profile consistent with CY14, we present an inversion of the model to estimate the key source and path parameters, namely the stress parameter and the anelastic attenuation. With these outputs, the effort in constructing a ground-motion logic tree for any PSHA dealing with crustal seismicity can be focused primarily on the estimation of the target-region characteristics and their associated uncertainties. The inversion procedure can also be adapted for any application in which different constraints might be relevant.
      Citation: Earthquake Spectra
      PubDate: 2022-01-28T07:08:31Z
      DOI: 10.1177/87552930211063221
       
  • How well can we predict earthquake site response so far' Site-specific
           approaches

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      Authors: Chuanbin Zhu, Fabrice Cotton, Hiroshi Kawase, Annabel Haendel, Marco Pilz, Kenichi Nakano
      First page: 1047
      Abstract: Earthquake Spectra, Ahead of Print.
      Earthquake site responses or site effects are the modifications of surface geology to seismic waves. How well can we predict the site effects (average over many earthquakes) at individual sites so far' To address this question, we tested and compared the effectiveness of different estimation techniques in predicting the outcrop Fourier site responses separated using the general inversion technique (GIT) from recordings. Techniques being evaluated are (a) the empirical correction to the horizontal-to-vertical spectral ratio of earthquakes (c-HVSR), (b) one-dimensional ground response analysis (GRA), and (c) the square-root-impedance (SRI) method (also called the quarter-wavelength approach). Our results show that c-HVSR can capture significantly more site-specific features in site responses than both GRA and SRI in the aggregate, especially at relatively high frequencies. c-HVSR achieves a “good match” in spectral shape at ∼80%–90% of 145 testing sites, whereas GRA and SRI fail at most sites. GRA and SRI results have a high level of parametric and/or modeling errors which can be constrained, to some extent, by collecting on-site recordings.
      Citation: Earthquake Spectra
      PubDate: 2022-01-15T05:16:14Z
      DOI: 10.1177/87552930211060859
       
  • Estimating shallow shear-wave velocity profiles in Alaska using the
           initial portion of P waves from local earthquakes

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      Authors: Andreas A Skarlatoudis, Hong Kie Thio, Paul G Somerville
      First page: 1076
      Abstract: Earthquake Spectra, Ahead of Print.
      The Alaska Regional Network and Transportable Array provide an invaluable waveform data set for studying ground motions in Alaska. However, the data set is useful only after the site effects at each station are well understood. Considering the large number of stations associated with these networks, it would be onerous to measure the sub-surface velocity structure beneath every station using geophysical exploration techniques involving arrays, such as active-source or passive-source non-invasive array methods. Instead, it is more economical to estimate the site conditions using waveforms recorded at the seismic stations. Most of the methods for estimating site response from recorded waveforms use the frequency-dependent ratio between the horizontal and vertical component of either ambient noise or S waves from earthquakes. We instead use the horizontal and vertical component of P waves to infer the sub-surface velocity structure. It has been demonstrated that the ratio of radial to vertical P waves is mostly sensitive to sub-surface shear velocity. Therefore, the sub-surface velocity structure can be estimated using an approach similar to teleseismic P receiver functions, but at much smaller scale and higher frequency. The results from this method are in good agreement with results from active-source or passive-source non-invasive array methods and have been widely used in the Central Eastern United States. The Alaska Regional Network and Transportable Array have recorded numerous earthquakes in the magnitude range of interest and at shallow depth, which provides an ideal opportunity for this study. VS30 is used to represent the site amplification of ground motions in all ground motion models that are used in generating the US Geological Survey’s National Seismic Hazard Maps, as well as in the professional practice of seismic hazard analysis. The results of this work provide a basis for improved site-specific hazard estimates in Alaska.
      Citation: Earthquake Spectra
      PubDate: 2022-02-26T04:46:36Z
      DOI: 10.1177/87552930211061589
       
  • Engineering site response analysis of Anchorage, Alaska, using site
           amplifications and random vibration theory

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      Authors: John Thornley, John Douglas, Utpal Dutta, Zhaohui (Joey) Yang
      First page: 1103
      Abstract: Earthquake Spectra, Ahead of Print.
      Earthquake records collected at dense arrays of strong-motion stations are often utilized in microzonation studies to evaluate the changes in site response due to variability in site conditions across a region. These studies typically begin with calculating Fourier spectral amplification(s) and then transition to performing engineering site response analyses. It has proven difficult to utilize Fourier spectral amplification(s) to define the appropriate elastic response spectr(um)/(a) for a site or sites. This is because, first, the ground motions recorded at these strong-motion stations have lower intensity and hence do not show the nonlinear site effects observed during higher-intensity earthquakes and, second, Fourier and response spectral amplitudes measure different aspects of ground motions. The strong-motion stations in Anchorage, Alaska, have been recording earthquakes in the region for the last three decades. This study utilizes a database of 95 events from 2004 to 2019 to calculate Fourier spectral amplifications at 35 stations using the generalized inversion technique (GIT). Estimated response spectra have been evaluated at each site by applying those Fourier spectral amplifications to a response spectrum of a reference station through random vibration theory (RVT). Correction factors are also applied within the approach to account for nonlinear site effects. This RVT-based approach is tested using ground motions recorded during the MW 7.1 2018 Anchorage Earthquake, and close matches between measured and predicted response spectra are found. The method is then compared with site response analyses using a calibrated 1D equivalent linear (EQL) model of the Delaney Park Downhole Array site. Estimated spectra using the RVT-based approach are, finally, compared with those using Next Generation Attenuation Subduction (NGA-Sub) and NGA-West2 ground-motion models. The proposed method provides a coherent and straightforward way to use GIT-derived Fourier spectral amplifications to directly estimate site-specific response spectra, accounting for nonlinear site effects and without requiring engineering characterization of subsurface soil conditions.
      Citation: Earthquake Spectra
      PubDate: 2022-01-27T07:32:25Z
      DOI: 10.1177/87552930211065482
       
  • Vertical ground-motion prediction equation and the vertical-to-horizontal
           spectral ratio for crustal earthquakes in Taiwan

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      Authors: Van-Bang Phung, Norman A Abrahamson, Bor-Shouh Huang, Chin Hsiung Loh
      First page: 1189
      Abstract: Earthquake Spectra, Ahead of Print.
      We develop a ground motion prediction equation (GMPE) for estimating the vertical ground motion amplitudes for crustal earthquakes in Taiwan. The data set used for the development includes strong-motion recordings mainly from Taiwan earthquakes (M3.5–7.6) and supplemented with large-magnitude earthquakes (M6.5–7.9) from other regions in the Pacific Earthquake Engineering Research Center (PEER) next generation attenuation (NGA)-West2 database. The functional form of the GMPE is similar to that of Phung et al. developed for the horizontal component (P20). The GMPE provides median and standard deviations of peak ground acceleration (PGA) and 5% damped pseudo spectral acceleration response ordinates of the orientation-independent average horizontal component of ground motion (RotD50) for the spectral period of 0.01–10 s. The vertical ground motion developed in this study can be paired with the P20 horizontal component model to estimate a vertical-to-horizontal (V/H) ratio that is unbiased. In the vertical component, we observe significant nonlinear site effects in the period of about 0.2–0.5 s, moderate nonlinear site effects in the period of about 0.01–0.04 s, and small nonlinear site effects in the period of about 0.05–0.075 s. Compared to our horizontal GMPE, anelastic attenuation is faster, VS30-scaling is reduced, and nonlinear site response is weaker for the vertical component.
      Citation: Earthquake Spectra
      PubDate: 2022-01-20T04:42:13Z
      DOI: 10.1177/87552930211061168
       
  • From information to public preparedness in the Cascadia Subduction Zone:
           Examining risk communication outcomes in Metropolitan Portland, OR

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      Authors: Carson C MacPherson-Krutsky, Brittany D Brand, Michael K Lindell
      First page: 1223
      Abstract: Earthquake Spectra, Ahead of Print.
      A Cascadia Subduction Zone (CSZ) earthquake will cause widespread damage along the Pacific Northwest (PNW) coast of the United States. It is, therefore, crucial to understand how to reduce future impacts across this region and assess current levels of household preparedness. Here, we examine whether decades of risk and preparedness campaigns have established protective knowledge and promoted hazard adjustments for residents of the Portland, Oregon metropolitan (PDX) region, an area where risk and preparedness campaigns have been increasing over the last decade. We also explore how PDX preparedness levels compare to those in other PNW regions using analogous data from multiple surveys over a 20-year time interval and assess PDX respondent’s perceptions of risk information sources. We find that 63% of PDX residents do not intend to “Drop, Cover, and Hold On” (DCHO) when earthquake shaking starts and that, although residents are generally aware of earthquake hazards in the area, they are less aware of the specific risks for their homes. Furthermore, PDX residents’ preparedness levels seem to be comparable to those recently surveyed in Washington, but somewhat less than those surveyed two decades ago in California, though more comprehensive data are needed to verify these results. We also find that people rate risk information provided by emergency managers and their websites as more accurate, understandable, relevant, and new than other sources. Our results suggest that significant gaps remain in translating broad awareness of the CSZ earthquake into personal knowledge and preparedness. This work provides guidance to PDX emergency educators for more targeted messaging and provides methods to measure preparedness variables in other regions for future comparisons. By paying close attention to preparedness gaps, local officials can use their limited resources more effectively to develop strategies to inform their communities and improve preparedness before a major earthquake strikes.
      Citation: Earthquake Spectra
      PubDate: 2022-01-17T07:59:02Z
      DOI: 10.1177/87552930211057582
       
  • An agent-based financing model for post-earthquake housing recovery:
           Quantifying recovery inequalities across income groups

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      Authors: Irene Alisjahbana, Ana Moura-Cook, Rodrigo Costa, Anne Kiremidjian
      First page: 1254
      Abstract: Earthquake Spectra, Ahead of Print.
      Past disasters have consistently led to unequal housing recovery for different economic groups, in large part, because of the difficulty of obtaining funding for low-income groups. Current earthquake recovery models simplify the financing process for homeowners to rebuild after earthquakes, and in consequence, cannot fully capture disparities in the recovery outcomes of economic groups. In this article, we develop an agent-based financing model for post-earthquake housing recovery. We focus on single-family, owner-occupied homes. The model includes funding from earthquake insurance, the Federal Emergency Management Agency, the Small Business Administration, the Department of Housing and Urban Development, private banks, Non-Governmental Organizations, and personal savings. We present a case study investigating the housing recovery financing in the economically diverse city of San Jose, California, following a hypothetical 7.0 Mw earthquake. By including the financial model in housing recovery simulations, we quantify inequalities in recovery time and total reconstruction completion between income groups. We complement the case study by evaluating several strategies to reduce these disparities and show that a combination of income-targeted funding and redistribution of construction crews can reduce inequalities in regional housing recovery.
      Citation: Earthquake Spectra
      PubDate: 2022-01-27T07:29:49Z
      DOI: 10.1177/87552930211064319
       
  • An analytical framework to assess earthquake-induced downtime and model
           recovery of buildings

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      Authors: Carlos Molina Hutt, Taikhum Vahanvaty, Pouria Kourehpaz
      First page: 1283
      Abstract: Earthquake Spectra, Ahead of Print.
      While modern seismic design codes intend to ensure life-safety in extreme earthquakes, policy-makers are moving toward performance objectives stated in terms of acceptable recovery times. This article describes a framework to probabilistically model the post-earthquake recovery of buildings and provide quantitative seismic performance measures, expressed in terms of downtime, that are useful for decision-making. Downtime estimates include the time for mobilizing resources after an earthquake and conduct necessary repairs. The proposed framework advances the well-established Federal Emergency Management Agency (FEMA) P-58 and Resilience-based Earthquake Design initiative (REDi) methodologies by modeling temporal building recovery trajectories to target recovery states, such as stability, shelter-in-place, reoccupancy, and functional recovery. The shelter-in-place recovery state accounts for relaxed post-earthquake habitability standards, in contrast with the reoccupancy recovery state that relates to pre-event habitability criteria. Analogous to safety-based codes, which specify a threshold for the probability of collapse under a given ground motion shaking intensity, this framework permits evaluating the probability of a building not achieving a target recovery state, for example, shelter-in-place, immediately after an earthquake, or, alternatively, the probability of achieving a target recovery state, for example, functional recovery, within a specified time frame. The proposed framework is implemented to evaluate a modern 12-story residential reinforced concrete shear wall building in Seattle, WA. The assessment results indicate that under a functional-level earthquake (roughly equivalent to ground motion shaking with a return period of 475 years), the probability of not achieving shelter-in-place immediately after the earthquake is 22%, and the probability of downtime to functional recovery exceeding 4 months is 88%, which far exceeds acceptable thresholds suggested in the 2015 National Earthquake Hazards Reductions Program (NEHRP) guidelines and FEMA P-2090.
      Citation: Earthquake Spectra
      PubDate: 2022-02-16T04:34:54Z
      DOI: 10.1177/87552930211060856
       
  • Probabilistic seismic source location and magnitude via inverse analysis
           of paleoliquefaction evidence

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      Authors: Ryan A Rasanen, Brett W Maurer
      First page: 1499
      Abstract: Earthquake Spectra, Ahead of Print.
      In regions of infrequent moderate-to-large earthquakes, historic earthquake catalogs are often insufficient to provide inputs to seismic-hazard analyses (i.e. fault locations and magnitude–frequency relations) or to inform ground-motion predictions for certain seismic sources. In these regions, analysis of relic coseismic evidence, such as paleoliquefaction, is commonly used to infer information about the seismic hazard. However, while paleoliquefaction studies have been performed widely, all existing analysis techniques require a priori assumptions about the causative earthquake’s location (i.e. rupture magnitude and ground motions can otherwise not be estimated). This may lead to inaccurate assumptions in some settings, and by corollary, erroneous results. Accordingly, this article proposes an inversion framework to probabilistically constrain seismic-source parameters from paleoliquefaction. Analyzing evidence at regional scale leads to (a) a geospatial likelihood surface that constrains the rupture location and (b) a probability distribution of the rupture magnitude, wherein source-location uncertainty is explicitly considered. Simulated paleoliquefaction studies are performed on earthquakes with known parameters. These examples demonstrate the framework’s potential, even in cases of limited field evidence, as well as important caveats and lessons for forward use. The proposed framework has the potential to provide new insights in enigmatic seismic zones worldwide.
      Citation: Earthquake Spectra
      PubDate: 2022-01-29T10:58:35Z
      DOI: 10.1177/87552930211056355
       
  • A relational database to support post-earthquake building damage and
           recovery assessment

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      Authors: Morolake Omoya, Itohan Ero, Mohsen Zaker Esteghamati, Henry V Burton, Scott Brandenberg, Han Sun, Zhengxiang Yi, Hua Kang, Chukuebuka C Nweke
      First page: 1549
      Abstract: Earthquake Spectra, Ahead of Print.
      Systematically collected and curated data sets from historical events provide a strong basis for simulating the physical and functional effects of natural hazards on the built environment. This article develops a relational database to support post-earthquake damage and recovery modeling of building portfolios. The current version of the database has been populated with information on the 3695 buildings affected by the 2014 South Napa, California, earthquake. The associated data categories include general building characteristics, site properties and shaking intensities, building damage and repair permitting (timing and type) information, and census-block-level sociodemographics. The Napa data set can be used to validate post-earthquake recovery simulation methodologies and explore the effectiveness of different modeling techniques in predicting damage. The database can be expanded to include other earthquakes and the overall framework can be adapted to other types of natural hazards (e.g. hurricanes, flooding).
      Citation: Earthquake Spectra
      PubDate: 2022-01-27T12:04:06Z
      DOI: 10.1177/87552930211061167
       
 
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