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- Seismic Performance Assessment of Steel Buildings Equipped with a New
Semi-active Displacement-Dependent Viscous Damper-
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Authors: Adnan Kiral, Reyes Garcia, Mihail Petkovski, Iman Hajirasouliha
Abstract: Journal of Earthquake and Tsunami, Ahead of Print.
This paper investigates numerically the seismic behavior of multi-degree-of-freedom (MDOF) systems with novel 2–4 direction and displacement-dependent (2–4DDD) and 2–4 Displacement-Velocity- (2–4DVD) Semi-Active (SA) controls. This study builds upon the novel SA 2–4DDD control system, in which the damper forces are controlled by inter-story drifts. For the first time, this paper investigates numerically the behavior of an MDOF system with 2–4DDD controls. A 3-story steel frame is modeled in OpenSees and then subjected to real earthquake records. The frame is modeled considering three control systems: (i) conventional passive nonlinear viscous dampers (NVDs), (ii) SA 2–4DDD dampers, and (iii) a new 2–4DVD SA damper. Parametric studies are conducted to determine the optimal parameters of 2–4DVD control in the designed frames. New design methodologies for MDOF systems with 2–4DVD and 2–4DDD controls are also proposed. The results are discussed in terms of inter-story drift, base shear force, acceleration, dissipated energy and required damper force. Results from Nonlinear Time History Analyses show that, compared to a frame with traditional NVDs, the inter-story drifts and base shear of the frame with 2–4DVD control are up to 72% and 32% lower, respectively. 2–4DVD control also reduces damping forces and acceleration by up to 60% and 87%, respectively, compared to 2–4DDD control. It is also shown that the 2–4DDD control was not stable in high-frequency earthquake records. Conversely, the new 2–4DVD control leads to smoother damping force changes between quadrants for the case study investigated in this paper. This study contributes toward the development of new seismic retrofitting dampers for nonlinear MDOF systems.
Citation: Journal of Earthquake and Tsunami
PubDate: 2024-08-08T07:00:00Z
DOI: 10.1142/S1793431124500222
- Influence of the Vertical Load Bearing Status on the Seismic Performance
of Weak-Joint-Type RC Frames Strengthened by the Wing Wall Installation
Method-
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Authors: Li Yuebing, Wang Hang, Xing Shuang, Shan Liang, Wang Xuanbo
Abstract: Journal of Earthquake and Tsunami, Ahead of Print.
“Strong column–weak beam, strong joint–weak member” is a core concept for the seismic design of buildings. For existing reinforced concrete (RC) frame buildings that do not satisfy this concept, installing RC wing walls beside existing columns is a simple and effective method for strengthening both columns and joints to promote a beam-hinging mechanism. In this study, a numerical simulation method is used to analyze the seismic performance of weak-joint RC frames strengthened by additional wing walls considering the column axial force ratio and to determine whether to consider the secondary load as a variable. The results show that when the secondary load is not considered, i.e. existing columns do not bear a load during the strengthening process, the strength, stiffness and energy dissipation of the structure increase with increasing axial force ratio, but the ductility of the structure decreases. When the secondary load is considered, the strength and initial stiffness of the frame are the greatest when the column axial force ratio is 0.4. When the axial force ratio is less than 0.4, the secondary load has less influence on the strength, stiffness and energy consumption. When the axial force ratio is greater than 0.4, the secondary load has a significant impact on the seismic performance of the strengthened structure, and the strength, stiffness, energy consumption and ductility are significantly greater than those in the case in which the secondary load is not considered. Additionally, the larger the axial force ratio is, the more significant the difference is. It is revealed that in engineering seismic strengthening using the wing wall installation method, the influence of secondary load on seismic performance should not be ignored, especially when the axial force ratio is large.
Citation: Journal of Earthquake and Tsunami
PubDate: 2024-08-07T07:00:00Z
DOI: 10.1142/S1793431124500179
- Effects of Spatial Variation in Relative Density on Seismic Behavior of
Saturated Sandy Ground-
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Authors: Masahiro Sawatsubashi, Makoto Ishimaru, Takaaki Kobayashi, Kenji Hiraga, Hideki Nakamura
Abstract: Journal of Earthquake and Tsunami, Ahead of Print.
Proper consideration of variations in soil properties and their effects is necessary to enhance the seismic safety of structures. In this study, the effect of spatial variations in the cyclic resistance ratio on seismic ground behavior was investigated. Initially, dynamic centrifuge model tests were conducted on sandy ground featuring a 20% mixture of weak zones with low relative density and on homogeneous sandy ground with no mixture of weak zones. Subsequently, an effective stress analysis was performed by modeling the distribution of weak zones in the centrifuge model tests. Finally, after confirming the validity of the parameter settings, several analytical models with different weak-zone distributions were generated and numerically analyzed using random field theory. The results indicate that a local mixing of approximately 20% weak zones has only a limited effect on overall ground behavior. However, differences were observed in the rate of increase and dissipation of the excess pore water pressure ratio and in the residual horizontal displacement.
Citation: Journal of Earthquake and Tsunami
PubDate: 2024-07-29T07:00:00Z
DOI: 10.1142/S1793431124500180
- Seismic Analysis of Segmental Tunnels Using Multi-Contact Joint-Based
Tunnel Model-
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Authors: Jiaxing Zhou, Peng Deng, Chao Zhang, Ziheng Geng, Renpeng Chen
Abstract: Journal of Earthquake and Tsunami, Ahead of Print.
Segmental tunnel is widely adopted in the urban transportation system, thereby its seismic resilience is a cornerstone for resilient cities. The segmental tunnel is an assembly of reinforced concrete segments, bolts, gaskets, gaps, etc., and exhibits highly nonlinear behavior when subjected to external loadings. Yet, in practice, its seismic response is generally estimated via a holistic modeling approach where the segmental tunnel is represented by a homogeneous beam or shell element with equivalent stiffness. Here, a multi-contact joint-based model is developed for a segmental tunnel, incorporating the nonlinearities embedded in the assembly with acceptable computational costs. The reinforced concrete segment is represented as the displacement-based fiber beam element, whereas the complex interaction among the configurations of the joint, i.e. bolt, gasket, and contacting concrete, is modeled via the zero-length section element. The proposed model’s accuracy is validated via a series of experimental data under three loading scenarios. A sensitivity analysis demonstrates that the mechanical response of segmental tunnels highly relies on the assembly configurations. The proposed model is implemented to investigate the seismic response of a typical segmental tunnel under various ground motions, demonstrating its applicability in seismic safety assessments, particularly in capturing the nonlinear response of segmental tunnels under high-intensity earthquakes.
Citation: Journal of Earthquake and Tsunami
PubDate: 2024-07-29T07:00:00Z
DOI: 10.1142/S1793431124500209
- Ambient Vibration-Based Seismic Evaluation of Long-Span Prestressed
Concrete Box-Girder Bridges Under Long-Duration, Near-Fault and Far-Fault
Ground Motions-
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Authors: Ahmet Can Altunişik, Fezayil Sunca, Barış Sevim
Abstract: Journal of Earthquake and Tsunami, Ahead of Print.
This study investigates the seismic behavior of long-span prestressed concrete box-girder bridges subjected to long-duration (LD) ground motions and spectrally equivalent near-fault (NF) and far-fault (FF) short-duration ground motions. For this purpose, the Kömürhan and Gülburnu Highway Bridges built with the balanced cantilever method using prestressed concrete box-girder were selected. This paper consists of two main sections. First, ambient vibration tests were conducted to identify the modal parameters of the bridges and calibrate the finite element models. Second, using three ground motion sets consisting of 42 acceleration records applied to the orthogonal and vertical directions of the bridges, the structural responses were evaluated and compared. In order to determine the type of ground motion that is critical for this type of bridge, these sets consist of 14 long-duration ground motions, 14 spectrally equivalent near-fault short-duration ground records, and 14 spectrally equivalent far-fault short-duration records. The comparison parameters considered for this study were displacements and internal forces in the piers and decks. The results strive to highlight the extent to which the duration and characteristics of the ground motion sets affect the structural behavior. Results indicate that the mean deck displacements of selected bridges obtained from FF short-duration records were nearly 10.70% and 7.44% less than those obtained from the LD and NF short-duration ground motions. These trends were also observed in the bridge piers. Moreover, increases of up to 17.54% and 26.65% in the mean shear forces of the piers under LD and NF short-duration ground motions were observed compared to those determined from the FF short-duration counterparts. Similar trends were observed in the bending moment values. It was also observed that far-fault short-duration records may have substantial consequences on such structures.
Citation: Journal of Earthquake and Tsunami
PubDate: 2024-07-19T07:00:00Z
DOI: 10.1142/S1793431124500192
- An Evolutionary Gravitational Neocognitron Neural Network for Earthquake
Parameters Observation in IoT System-Based Earthquake Early Warning-
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Authors: K. Manikannan, Premendra Janardan Bansod, Mageswari Murugan, Sivaramakrishnan Subbaram
Abstract: Journal of Earthquake and Tsunami, Ahead of Print.
An earthquake early-warning system (EEWS) is essential for preserving human life. In terms of disaster management and EQ risk reduction, quickly determining the earthquake’s (EQ’s) magnitude and position is important. To prevent an EQ catastrophe, these parameters can be transmitted over an IoT network. The Evolutionary Gravitational Neocognitron Neural Network (EGNNN), a novel technique for real-time earthquake parameter observation, is introduced in this paper to enhance earthquake early warning (EEW) systems. The proposed framework uses various sophisticated data processing methods to analyze publically accessible earthquake data from sources like the Japan Meteorological Agency. The Morphological Filtering Extended Empirical Wavelet Transformation (MFEEWT) method is first used to pre-process seismic waveform input, significantly lowering noise levels in the data. After that, from the pre-processed waveforms the relevant features are extracted via the Fast Discrete Curvelet Transform with Wrapping (FDCT-WRP) and a Stacked Autoencoder (SAE). The EGNNN, an innovative neural network model created for earthquake parameter prediction, specifically location and magnitude, uses these extracted features as input. The Osprey optimization algorithm (OOA) is employed to enhance the EGNNN model. A crucial component of EEW systems, dependable and quick alert delivery is ensured by the proposed system’s integration with an Internet of Things (IoT) framework. The EGNNN swiftly evaluates earthquake parameters and sends this vital data to a centralized IoT system, enabling pertinent entities to act promptly. Performance evaluation is conducted on the Python platform, comparing the proposed technique with existing methods. The proposed method EGNNN-EPO-IoT achieves a higher warning time of 23.34%, 3.45%, and 7.86%; 12.23%, 32.21%, and 22.09% higher accuracy compared to the other existing techniques such as 3S-AE-CNN-EPO-IoT (3 sec-Autoencoder-Convolutional neural network-Earthquake parameter observation-IoT), XGB-EPO-IoT (Extreme Gradient Boosting-EPO-IoT), and SVM-EPO-IoT (Support Vector Machine-EPO-IoT).
Citation: Journal of Earthquake and Tsunami
PubDate: 2024-06-28T07:00:00Z
DOI: 10.1142/S1793431124500167
- Fuzzy Logic-Based Fragility Curve Development for Steel Moment-Resisting
Frames Considering Uncertainties in Seismic Response-
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Authors: Fooad Karimi Ghaleh Jough
Abstract: Journal of Earthquake and Tsunami, Ahead of Print.
In this paper, a comprehensive range of uncertainties is considered to assess the seismic abilities of a moment-resisting system. To incorporate the parameter of construction quality, which has a descriptive nature, a suitable fuzzy logic engine has been developed. This engine, for the first time, addresses the quantitative assessment of construction quality parameters based on linguistic variables, including map accuracy, worker skills, material quality, and site supervision conditions. Instead of using random selection, a self-organizing map (SOM) algorithm is employed to carefully select strong ground motion records, reducing time costs. By applying incremental dynamic analysis (IDA) results, analytical equations are derived for the response surface method. These equations determine the collapse fragility’s mean and standard deviation. The material quality is modeled using the fuzzy inference engine, with the coefficient of logarithm response surface. Collapse fragility curves are created by taking into account many of their material quality values and utilizing the fuzzy model to estimate the modeling parameter based on the logarithm regression coefficients. These curves take into consideration various sources of uncertainty. In countries with inadequate material quality control, it is important to take cognitive uncertainty into account when developing fragility curves. This will help improve the overall risk management strategy.
Citation: Journal of Earthquake and Tsunami
PubDate: 2024-06-15T07:00:00Z
DOI: 10.1142/S1793431124500143
- Seismic Resistance and Performance Evaluation of Masonry Dwellings After
the February 6, 2023, Kahramanmaraş Earthquake Sequence in Türkiye-
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Authors: Onur Onat, Burak Yön, Ali Uslu, Mehmet Emin Öncü, Sadık Varolgüneş, İbrahim Baran Karaşin, Mesut Gör
Abstract: Journal of Earthquake and Tsunami, Ahead of Print.
On February 6, 2023, two catastrophic earthquakes occurred on the East Anatolian Fault. The earthquakes had magnitudes of Mw = 7.7 and 7.6 and struck Kahramanmaraş-Pazarcık and Kahramanmaraş-Elbistan, respectively. The Kahramanmaraş-Pazarcık earthquake was triggered at 04:17 local time on the Dead Sea Fault (a branch of the East Anatolian Fault). The last earthquake on the addressed fault occurred about 500 years ago. The recorded peak ground acceleration (PGA) at the Pazarcık station reached 2.05g. In addition, the Pazarcık earthquake triggered two independent earthquakes, the Nurdağı and Islahiye earthquakes, which occurred 10 min later than the Pazarcık earthquake. However, the last earthquake, with its epicenter in Kahramanmaraş-Elbistan, struck at 13:24 local time. The recorded PGA for the Elbistan earthquake is 0.68g. This study aims to present the fault rupture mechanism of the February 6, 2023, Kahramanmaraş earthquakes, earthquake characteristics, and to evaluate the performance of masonry dwellings during the Kahramanmaraş earthquake doublet, which affected 10 provinces and numerous towns and villages. This paper also aims to illustrate the damage and failure mechanisms of the masonry dwellings, despite unexpectedly high accelerations that exceeded the design spectrum in the field, specifically in Kahramanmaraş, Gaziantep, Hatay, and Malatya, according to the current earthquake code in use.
Citation: Journal of Earthquake and Tsunami
PubDate: 2024-05-31T07:00:00Z
DOI: 10.1142/S1793431124500131
- Effects of Floating States on Collision Forces of Drifting Containers
Caused by Solitary Wave Inundation-
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Authors: Taegeon Hwang, Taeyoon Kim, Jiwon Kim, Yeonjoong Kim, Woo-Dong Lee
Abstract: Journal of Earthquake and Tsunami, Ahead of Print.
The overtopping-inundation process of a tsunami results in the collisions of drifting objects on the coast, which damage structures, thereby increasing the risk of collapse. This study conducted laboratory experiments on the collision between a drifting container caused by the overtopping-inundation process of a solitary wave and a fixed port crane’s leg. The movement trajectory and velocity of the container as well as the collision velocity by solitary wave inundation, were analyzed using motion analysis software. Overall, increasing solitary wave scale, collision velocity, and drifting object weight and decreased distance between the two objects tended to increase the collision force. However, different experiment results were also obtained due to pitching in objects that fully floated without bottom friction owing to the solitary wave bore. This resulted in line-to-surface collisions. Thus, surface-to-surface contact occurred under the incomplete floating condition owing to the difficulty because of interference with the bottom; however, the collision force decreased under complete floating conditions owing to line-to-surface contact. Therefore, the contact condition according to the floating behavior must be considered a parameter while predicting the collision forces of drifting objects. Thus, surface-to-surface contact occurred under the incomplete floating condition owing to the difficulty because of interference with the bottom; however, the collision force decreased under complete floating conditions owing to line-to-surface contact. Therefore, the contact condition according to the floating behavior must be considered a parameter while predicting the collision forces of drifting objects.
Citation: Journal of Earthquake and Tsunami
PubDate: 2024-04-24T07:00:00Z
DOI: 10.1142/S1793431124500106
- Regional and Site-Specific Ground Motion Model for Probabilistic Seismic
Hazard Analysis in Taiwan: A Case Study of I-Lan-
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Authors: Van-Bang Phung, Yu-Wen Chang, Chin-Hsiung Loh, Bor-Shouh Huang, Vinh-Long Ha, Cong-Nghia Nguyen, Dinh-Hai Pham
Abstract: Journal of Earthquake and Tsunami, Ahead of Print.
In this study, a probabilistic seismic hazard analysis (PSHA) using a traditional approach with a simple logic tree that handles a single-site sigma is developed to present a site-specific ground motion hazard. The analysis relies on the accelerometer data collected from the I-Lan Plain, a deep sedimentary basin in Northeastern Taiwan where hundreds of earthquake sequences (with [math] = 4.0–7.6) were recorded by the Taiwan Strong Motion Instrument Program (TSMIP) network between 1992 and 2016. The performance of PSHA on soil and hard sites is evaluated from two representative instrumented sites (ILA048 and ILA025), using residual measures available from a ground motion model (GMM) developed by Phung et al. [] (referred to as Ph23), from which the uncertainties in site terms ([math] and single-site sigma ([math] are estimated. We address key conceptual issues in the current PSHA approach and introduce a new region- and site-specific PSHA approach in which (1) site-to-site variability ([math] is estimated as a random variance in a mixed effects GMM regression and (2) the GMM site-specific single-site sigma ([math] is replaced with a generic site-corrected aleatory variability ([math]). Comparison of the region- and site-specific hazard curves from our method against the traditional method estimates at two well-recorded sites in the I-Lan region shows an approximate 50% difference in prediction ground motion values considering for 2% and 10% probability of exceedance in 50 years.
Citation: Journal of Earthquake and Tsunami
PubDate: 2024-04-16T07:00:00Z
DOI: 10.1142/S179343112450009X
- Improving a Conventional Connection of Beam-to-Weak Axis of H-shaped
Column to Modify Load Path in Panel Zone-
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Authors: Seyed Rasoul Mirghaderi, Ghazaleh Taheri, Samira Ebrahimi
Abstract: Journal of Earthquake and Tsunami, Ahead of Print.
This study aims to propose an improvement to the conventional connection of beam-to-weak axis of H-shaped columns with in-plane load paths and to compare the improved connection with the conventional one. The conventional connection detail consists of continuity plates and face plates, while the improved connection detail, in addition to the previous components, has a plate perpendicular to the column web (middle panel zone) acting as a panel zone. A numerical study using ABAQUS was conducted, and the study results showed that the most appropriate value for the middle panel zone thickness is equal to the column flange thickness, and it should be designed for 30% of the force demand induced by the beam bending moments. Furthermore, the study findings indicated that the proposed connection resulted in an average of 59.5% decrease in the force demands induced to the panel zone in comparison with the conventional connection. In addition, it was observed that the force demand on the face plate experienced the most decrease due to reducing the out-of-plane performance of the face plate in the improved connection models. Moreover, the results showed that the improved connection models experienced lower levels of von Mises stress, approximately 35.7% less than the conventional connection models.
Citation: Journal of Earthquake and Tsunami
PubDate: 2024-04-06T07:00:00Z
DOI: 10.1142/S1793431124500015
- Design of an Overhead Water Tank as a Passive Tuned Damper Using an
Innovative Support System Adaptive to Liquid Depth Fluctuation in the Tank
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Authors: Tanmoy Konar
Abstract: Journal of Earthquake and Tsunami, Ahead of Print.
Difficulty in maintaining tuning due to water depth fluctuation makes overhead water tanks (OWTs) ineffective as tuned liquid or mass dampers. Recently, a semi-active damper involving OWT, that varies the stiffness of the tank-supporting columns with liquid depth variation to maintain the impulsive frequency of the tank constant at a value required for tuning, has been proposed. In this paper, the concept is extended to develop a passive tuned damper involving the OWT (PTD-OWT), which is more reliable, cost-effective, and has a simpler configuration than its semi-active counterpart but achieves the same objective as the latter. For the PTD-OWT, a novel mechanism involving a spring-supported platform, a rigid frame, and tank-supporting columns is developed. The working principle and mathematical model of the PTD-OWT are presented followed by an illustrative design example considering the host building undergoing base excitation. The results revealed that the PTD-OWT remains tuned and thereby performs consistently despite wide variations in water depth in the tank. Significant reductions have been achieved by the PTD-OWT in peak and root-mean-square displacement and acceleration responses of the structure for a variation in liquid depth between 100% full tank to empty tank condition, with the maximum fall in control achieved as only 6.8%. A comparison of PTD-OWT is made with the case when the tank is designed as a conventional passive tuned mass damper (TMD) without the provision for maintaining tuning. The conventional mass damper suffers significant performance degradation as liquid depth fluctuates in the tank.
Citation: Journal of Earthquake and Tsunami
PubDate: 2024-03-27T07:00:00Z
DOI: 10.1142/S1793431124500076
- Seismic Resilience Scenario of Algerian Buildings’ Context: Blida
City Case Study-
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Authors: Nacim Yousfi, Mounir Ait Belkacem, Nabila Guessoum, Mahmoud Bensaibi
Abstract: Journal of Earthquake and Tsunami, Ahead of Print.
Several studies have been carried out to assess the building’s seismic vulnerability, to mitigate the seismic risk in urban areas, which is one of the most devastating natural hazards causing considerable economic and human losses. These studies must be incorporated to improve the planning of urban areas to have resistant and resilient cities in case of disasters. The seismic feedback has shown that the build-back-better concept has a direct impact on the city’s economic growth. In this paper, the existing buildings’ resilience is assessed, in order to highlight the capacity of these last to keep the functionality when an earthquake occurs. This building’s resilience has been determined for three types of structures: masonry, reinforced concrete and steel, according to the reconstruction time, the reconstruction cost and the damage state. This last has been assessed from empirical fragility curves developed using the log normal distribution for five structures typologies (Unreinforced masonry; reinforced masonry; RC frame; RC shear walls/Mixed RC frame-RC shear walls and steel structures). A seismic resilience scenario was performed using a geographic information system (GIS) and applied for the Blida city (Algeria) classified as a high seismic zone according to Algerian seismic regulations. According to the results found, the old districts of the Blida city, built mainly during the so-called pre-code period, will not be resilient in case of disaster. The other districts built later in the low-code and high-code periods will have, respectively, medium and good functionality.
Citation: Journal of Earthquake and Tsunami
PubDate: 2024-03-21T07:00:00Z
DOI: 10.1142/S1793431124500052
- Effects of Inclination of Longitudinal and Vertical Acceleration
Components of Near-Field Earthquake Records on Seismic Responses of Pile
Foundation-Superstructure Systems in Liquefiable Soil Bed-
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Authors: Kooshyar Fadayi Asiabsary, Navid Hadiani, Amir Hossein Eghbali, Seyed Mohammad Ali Sadreddini
Abstract: Journal of Earthquake and Tsunami, Ahead of Print.
The inclination angle of such components with respect to the principal orthogonal axes cannot be neglected in the direct seismic analysis of soil-foundation-superstructure systems, specifically in a piled liquefiable soil bed. This study validated numerical simulations and numerically modeled a concrete moment frame on a pile foundation within a liquefiable soil bed. The direct seismic analysis of the superstructure-foundation-soil system was carried out in a single step (through nonlinear dynamic time-history analysis) under longitudinal and vertical near-field seismic acceleration component records. The effects of the inclination of longitudinal and vertical acceleration components on the seismic responses of the soil-foundation-superstructure system in the liquefiable soil bed were explored, evaluating the critical inclination based on the near-field earthquake magnitude. It was observed that the simultaneous application of longitudinal and vertical near-field seismic acceleration components substantially changed the liquefiable soil bed drift of the pile foundation-superstructure system, significantly altering [math] in depth, particularly in the middle of the pile depth. The change in [math] and its effects on the seismic responses of the superstructure and piles (interstory drift and pile shear force and bending moment) were different upon a 30° change (rotation) in the acceleration records from 0 to 90° with respect to the orthogonal principal axes.
Citation: Journal of Earthquake and Tsunami
PubDate: 2024-03-05T08:00:00Z
DOI: 10.1142/S1793431123500422
- Can the Thermal Infrared Radiation Anomalies Reported Before Earthquakes
be a Precursor'-
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Authors: Jeen-Hwa Wang
Abstract: Journal of Earthquake and Tsunami, Ahead of Print.
Twenty-seven earthquakes in Taiwan with local magnitudes [math] and focal depths d = 8.0−215.8[math]km were preceded by thermal infrared radiation (TIR) anomalies. The data are taken as an example to investigate the mechanisms of generating the TIR and to examine whether the TIR anomalies can be considered as a precursor or not. Let [math] and [math] be the largest number of days before forthcoming earthquakes when the anomalies are observed in the day-time and the night-time, respectively. The precursor time, T, for an event, is the larger value of [math] and [math]. The plots of both T vs. [math] and [math] vs. [math] are scattered. Regardless of two data points with abnormally large [math] values, it seems able to recognize a positive correlation between [math] and [math]. Among the 27 earthquakes, 8 events were proceeded by Rn concentration changes whose precursor times are [math] days. For most of the eight events, [math] is much longer than either [math] or [math]. Hence, the model of outflow of gases from the depths to the ground surface for describing the Rn concentration changes cannot interpret the TIR anomalies. Based on rock mechanics, the temperature rise, [math], is generated by frictional heating due to preseismic slip. That the TIR anomalies discontinuously appeared before earthquakes and the occurrence times vary for different events is inconsistent with the processes of generation of frictional heating caused by preseismic slip on a few shallow faults in the source areas before forthcoming earthquakes. Since theoretical results and observations are not consistent, the answer to the title of this study is negative.
Citation: Journal of Earthquake and Tsunami
PubDate: 2024-02-26T08:00:00Z
DOI: 10.1142/S1793431124500039
- Theoretically Derived Transfer Functions and Specific Framework for
Simulating Spatially Varying Seismic Underground Motions of
Media-Transition Site-
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Authors: Guohuan Liu, Xinyang Li
Abstract: Journal of Earthquake and Tsunami, Ahead of Print.
Extended projects usually undergo different motions at their supports located at varying soil property conditions when an earthquake occurs. A theoretical framework including the key transfer function is proposed for simulating multi-support seismic underground motions in media-transition sites. First, a multi-layer media-transition site is illustrated. Then, the transfer function is theoretically derived and given explicitly using seismic wave propagation theory and fulfilling rigorously continuous boundary conditions. The obtained transfer function is the critical factor to calculate the underground Auto-Power Spectral Density (A-PSD). Meanwhile, the derivation and illustration of the other key factor (i.e. underground coherency function) is also given and the essential effect caused by media transition is further disclosed. The underground Cross-Power Spectral Density (C-PSD) is obtained by combining the underground coherency function with the transfer function. The underground Power Spectral Density Matrix (PSDM) is finally assembled by combining the A-PSD with C-PSD. Subsequently, multi-support seismic motions at varying depths of the media-transition site are generated, and its accuracy is further validated. Additionally, a numerical study is conducted to demonstrate the effect of water and soil phase on transfer functions and the underground seismic motions among dual-phase and media-transition sites. Results show the difference of seismic underground motions in two sites is obvious. This paper can provide a specific and feasible methodology for generating the multi-support seismic underground motions.
Citation: Journal of Earthquake and Tsunami
PubDate: 2024-02-19T08:00:00Z
DOI: 10.1142/S1793431123500410
- Simulation of Strong Ground Motions From the October 30, 2020, Samos
Earthquake and Validations Against Observed Records, Intensity
Distributions, and Damages in Izmir, Türkiye-
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Authors: Shaghayegh Karimzadeh, Aysegul Askan
Pages: 1 - 24
Abstract: Journal of Earthquake and Tsunami, Ahead of Print.
An earthquake of Mw = 7.0 occurred on October 30, 2020, in the Aegean Sea near Samos Island, which caused severe structural damage in Bayraklı, Izmir (Türkiye), located around 70 km from the epicenter. To investigate the source, path, and site effects, ground motions recorded in Western Anatolia are simulated using the stochastic finite-fault method based on a dynamic corner frequency approach. The input model parameters are calibrated using the recorded motions at selected 10 stations within an epicentral distance of less than 100 km. The soil amplifications are modeled using horizontal-to-vertical spectral ratios and generic amplification factors. At most stations, including a few within Izmir Bay, amplitudes and frequency contents are modeled closely. Minor discrepancies within particular frequency bands can be attributed to insufficient representation of the local site effects. Finally, distributions of observed and simulated felt intensities are found to be consistent.
Citation: Journal of Earthquake and Tsunami
PubDate: 2024-06-25T07:00:00Z
DOI: 10.1142/S1793431124500155
- Rigorous Solution for the Kinematic Response of Single Disconnected Piles
Subjected to Vertically Incident P-Waves-
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Authors: Chenglong Hu, Qijian Liu, Tao Deng, Lei Zeng
Pages: 1 - 19
Abstract: Journal of Earthquake and Tsunami, Ahead of Print.
A rigorous solution for the kinematic response of the disconnected piles under vertically incident P-waves is presented. A new soil–pile column model is proposed with two fictitious soil columns as the extensions of the shaft along the pile top and tip. The discontinuity of the pile at the two ends is modeled using the Heaviside function to simulate the continuity of the soil–pile column. The total displacement of the soil is divided into the free-field and scattered components. The displacement of the soil–pile system is calculated in terms of the method of separation of variables and the soil–pile interaction. A parametric study indicates that for the disconnected pile, the displacement at the pile top increases significantly with the increase of the cushion thickness, and its effect on the scattered field is weak. The axial force of the disconnected pile decreases gradually with the increase of the cushion thickness. The displacement and axial force of the disconnected pile are significantly influenced by the slenderness ratio of the pile.
Citation: Journal of Earthquake and Tsunami
PubDate: 2024-03-25T07:00:00Z
DOI: 10.1142/S1793431124500064
- Rapid Crisis Response in Resilient Cities: Emergency Response to and
Reconnaissance of Earthquake Disasters in Taiwan-
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Authors: Siao-Syun Ke, Chih-Hao Hsu, Ching-Yuan Yang
Pages: 1 - 20
Abstract: Journal of Earthquake and Tsunami, Ahead of Print.
The devastating Chichi earthquake in Taiwan in 1999 highlighted the importance of disaster prevention and relief operations. In response to the challenge of extreme events and compound disasters, the National Science and Technology Center for Disaster Reduction (NCDR) contributes to operations at the Central Emergency Operation Center (CEOC) of Taiwan by providing integrated information and timely suggestions, and it delivers a common operational picture to central and local governments through a decision support system. This study was undertaken to explore the emergency response towards the reconnaissance of earthquake disasters in Taiwan to illustrate how resilient cities ensure rapid crisis response with a focus on the NCDR disaster response decision support system. This study examines the decision support system used following the 2016 ML 6.6 Meinong earthquake. The results demonstrate that the first line of relief for the emergency response commander is data-driven decision-making.
Citation: Journal of Earthquake and Tsunami
PubDate: 2024-03-25T07:00:00Z
DOI: 10.1142/S1793431124500088
- Seismic Isolation Effects on Elevated and Ground-Supported Flexible
Concrete Cylindrical Tanks Under Bi-Directional Excitation Using an
Advanced Mechanical Model-
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Authors: Shamsedin Hashemi, Mohammad Hossein Aghashiri, Atefeh Ehteshami, Reza Kianoush
Pages: 1 - 38
Abstract: Journal of Earthquake and Tsunami, Ahead of Print.
In this paper, the effectiveness of seismic isolation using lead rubber bearings (LRBs) and friction pendulum systems (FPSs) for slender and broad, grounded and elevated tanks (two seat locations of isolation systems in elevated tanks) is investigated under bi-directional excitation of up to 10 records of earthquakes. An analytical mechanical model for a flexible, concrete cylindrical tank, taking into consideration the effect of wall mass and sloshing, is used. The assumptions underlying the mechanical model are basic equations of the motion according to the theory of fluid dynamics. So, the assumptions are more realistic and the results therefore are more accurate than the previous models. The results show that by selecting the best mechanical properties of base isolation systems, reductions of seismic base shear in the grounded broad tanks are around 35% and 30% and for the grounded slender tanks are around 55% and 58% in the x- and y-directions, respectively. Maximum total hydrodynamic pressure is reduced considerably by about 40% on average in all grounded and elevated models. As a result of isolation, elevated tanks are concluded to be better candidates in terms of more effective application of seismic isolation.
Citation: Journal of Earthquake and Tsunami
PubDate: 2024-03-16T07:00:00Z
DOI: 10.1142/S1793431124500027
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