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Zeitschrift für Geomorphologie
Journal Prestige (SJR): 0.309  Citation Impact (citeScore): 1 Number of Followers: 5  Subscription journalISSN (Print) 0372-8854 - ISSN (Online) 1864-1687 Published by Schweizerbart Science Publishers  [23 journals]
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- Effect of the antecedent precipitation on the occurrence of landslides:
Examples from the Central Uplands in Germany-
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Effect of the antecedent precipitation on the occurrence of landslides: Examples from the Central Uplands in GermanyRupp, Stefan
Zeitschrift für Geomorphologie, (2022), p. - AbstractPrecipitation is considered one of the most important triggering factors of landslides. In addition to precipitation as the actual triggering event, the antecedent precipitation may be of great importance, as this can lead to an increase of the soil water content and the pore water pressure and, thus, to a decisive slope instability. In the present study, 236 landslide events and daily precipitation records of 55 precipitation stations in the Central Uplands in Germany are used to analyze the relationship between the occurrence of landslides and the antecedent precipitation for the first time. In addition, the precipitation on the day of the landslide event was used to determine the degree of influence of the two parameters on the occurrence. To ensure a good representation, the nearest station was assigned to each landslide. The analyses show that the antecedent precipitation is generally of great importance for the occurrence of landslides all year round. Especially in the winter months, the antecedent precipitation, as the predisposing factor, has a major impact on the occurrence of landslides which is expressed by the decrease of the slope stability by an increasing soil water content. This influence of the antecedent precipitation is also of great importance in the summer months in order to create the conditions for the possible occurrence of landslides. The precipitation on the day of the landslide, i.e. short-term heavy precipitation events, is not so decisive for the triggering in winter, which is why the antecedent precipitation is also regarded as the trigger here. In summer, on the other hand, the precipitation on the day of the landslide is necessary as a trigger to an increasing degree. The results of this study could be useful for further interdisciplinary analyses in the future, taking into account the specific geological, geomorphological and climatological conditions of the landslide sites, in order to investigate the complex relationship between landslide occurrences and influencing and triggering factors even more comprehensively.
PubDate: Mon, 11 Jul 2022 00:00:00 +000
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- A multisource approach for tidal flat study. Example of the Baie des Veys,
Normandy, France-
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A multisource approach for tidal flat study. Example of the Baie des Veys, Normandy, FranceDeroin, Jean-Paul; Guillaneuf, Alexandra; Laratte, Sébastien
Zeitschrift für Geomorphologie, (2022), p. - AbstractThe Baie des Veys along the Channel in the north-west of France is a dynamic estuary, with intertidal sandbanks and subtidal channels undergoing constant migration. This relatively small tidal flat (37 km2) is easily accessible in the field and allow field observation to be done. This embankment lost about half its surface since two centuries, due to human activities, particularly land reclamation. The main objectives of this study were to map the morphological and geological units of the tidal flats, to evaluate the nature and the distribution of the sediments, to identify the causes of the variations, and then to estimate the long-term sediment balance in the bay and look at its link with the environmental changes. In the Baie des Veys the flood current is higher than the ebb current. The tidal flat is then characterized by tidal wedges linked to the flood, independent from the main channels mainly used during ebb tide. Remote sensing data such as aerial photographs or satellite images offer the advantage of showing aspects of the tidal flat that are not recorded on any standard map. More generally, the role of the tidal range is emphasized, along with the hour of acquisition. A 6 km-long cross-section of the tidal flat is surveyed from 2006 onward. Samples are regularly taken along the profile and their position controlled using a GPS receiver. Carbonates and organic matter content show recent increasing rates which can be related to the extent of the shell fishing. Spartina clumps develop and contribute to trap fine sediments (clays and silts) for more than one century. Since the last land reclamation program (1972), halophytic plants show a significant progression in the upper part of the tidal flat, the so-called schorre, but not in front of the main bank (Ravine Bank) in the central part of the bay. The sedimentary changes induce also deep biological changes, with a modification of the ecosystem. The Baie des Veys faces sea level rise with specific reaction such as the re-opening of a polder to the sea in 1991. This French tidal flat is a good model for studying the link between natural and human activities in a macrotidal bay located in temperate zone.
PubDate: Mon, 11 Jul 2022 00:00:00 +000
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- Quantification of deflation-induced soil loss on chernozems: Field
protocol and sediment trap development based on wind tunnel experiments-
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Quantification of deflation-induced soil loss on chernozems: Field protocol and sediment trap development based on wind tunnel experimentsFarsang, Andrea; Szatmári, József; Bartus, Máté; Tiszlavicz, Ádám; Barta, Károly
Zeitschrift für Geomorphologie, (2022), p. 329 - 341AbstractToday, chernozem soils under intensive cultivation have also become sensitive to deflation. The deflation sensitivity of an area can be characterised by trapping the material transported away from a specific area during a wind event. For this purpose, numerous sediment sampling tools are used in international research. Sediment traps aim to analyse the accurate quantitative and qualitative parameters of aeolian sediment (both finer and coarser fractions) and study aeolian processes and their intensity. The types of samplers used for sampling aeolian sediment will vary depending upon the sediment type to be measured. Our earlier field experiments on chernozem soils showed that sediment traps (such as MWAC, BSNE, SUSTRA, POLCA) developed for sandy soils and recommended by the international literature do not work with proper efficiency on loamy and clay soils with degraded texture. One of our main objectives was to develop a suitable trapping device (WAST: Wet Active Sediment Trap), an active horizontal trap that can sample at different heights, is an isokinetic, wet sediment trap, and has a good efficiency in all substantial particle size ranges. We conducted the efficiency analyses with an MWAC sediment trap, which appear to be the most popular for sediment moving field studies. The combined use of the field wind tunnel, the field platform scale placed under the wind tunnel, as well as the WAST trap, which sampled at three different heights and was positioned in the outlet opening of the wind tunnel, made it possible to estimate soil loss induced by various wind events more accurately and more efficiently. The efficiency of the WAST trapping device proved to be three times more on average than that of the MWAC trapping device when sampling loamy soils. The median calculated for the efficiency values is 27% for the MWAC and 87% for the WAST.
PubDate: Tue, 15 Mar 2022 00:00:00 +000
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- The lower coasts of the Gulf of Gabès and their wetlands (South-East
Tunisia): a geoarchaeological study of the landscape evolution and human
occupation in Late Holocene-
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The lower coasts of the Gulf of Gabès and their wetlands (South-East Tunisia): a geoarchaeological study of the landscape evolution and human occupation in Late HoloceneOueslati, Ameur
Zeitschrift für Geomorphologie, (2022), p. 343 - 363AbstractThe Gulf of Gabès is situated in the south eastern part of the Tunisian coasts, characterized by its semiarid climate and low topographies with extensive wetlands. Several studies aiming at the knowledge and the reconstruction of the paleoenvironments and the evolution of the human presence were conducted in the past. However, relating to the evolution during Late Holocene these studies were generally limited to a narrow coastal fringe and mainly emphasized by a geological approach. These studies focused primarily on sea-level variations. This paper is based on a methodology considering both geomorphological and archaeological data. It takes into account the sea as an essential morphogenic agent but, at the same time, considers the continental and structural factors. The use of archaeological data makes it possible to appreciate the impact of these factors. It also helps to a better understanding of the evolution of human societies and the ways in which they adapted to their environment. During the Holocene, it appears that despite local variations, alluvial plains and wetlands, have experienced each of them two periods leading to their extension. For the alluvial plains, the favorable episodes took place in the presence of the Neolithic people and under the eyes of the Romans and after their leaving. For wetlands, the favorable episodes coincided with two periods characterized by sea-level rise. The first was witnessed by the Neolithic populations. The second was recorded after the Antiquity and is continuing today. Over the course of this history and depending on whether the trend has been towards sea-level rise or the arrival of large quantities of alluvium to the coast, the wetlands have extended or been reduced or erased. This evolution has impacted man behavior and explains his choice for certain locations today materialized by archaeological remains.
PubDate: Tue, 15 Mar 2022 00:00:00 +000
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- Sediment dynamics and hydrodynamical processes in the Danube Delta
(Romania): A response to hydrotechnical works-
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Sediment dynamics and hydrodynamical processes in the Danube Delta (Romania): A response to hydrotechnical worksDuţu, Florin; Duţu, Laura Tiron; Catianis, Irina; Ispas, Bogdan-Adrian
Zeitschrift für Geomorphologie, (2022), p. 365 - 378AbstractThe Sulina channel is one of the three distributaries of the Danube Delta. The present-day evolution of the Sulina branch is controlled by the continuous anthropic works and interventions, realised in the past 200 years, such as groins, cut-offs, protection of the banks with rock blocks, dredging for navigation scope. These anthropic works had direct and important effects on the grain size distribution and dynamics of the bed sediments. In the current study, the river dynamics and sediment characteristics were investigated using the field observations data from May and September 2019 in two different hydrological conditions. The results expressed that the sediments are fine fraction (medium and fine sand, and silt, 0.17 mm in May and 0.24 mm in September), moderately and poorly sorted. The entrainment threshold of sediments (Shields diagram, 1936) reveals the mode of transport of particles and analyse the sediment dynamics and temporal changes in the discharge of the Sulina channel. We found that the alternation of erosional and depositional areas, lead to the groin’s presence, significantly affects the sediment distribution along the fluvial channel.
PubDate: Tue, 15 Mar 2022 00:00:00 +000
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- Temporal patterns of suspended sediment dynamics in a Mediterranean
mountainous catchment-
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Temporal patterns of suspended sediment dynamics in a Mediterranean mountainous catchmentTuset, Jordi; Vericat, Damia; Estany, David; Batalla, Ramon J.
Zeitschrift für Geomorphologie, (2022), p. 379 - 405AbstractThe relation between discharge and suspended sediment transport in Mediterranean mountain catchments is typically non-linear. This is related to spatio-temporal variability in sediment sources and the intensity and distribution of precipitation which together control sediment supply and the downstream transport of suspended material. This study analyses suspended sediment dynamics in a meso-scale forested Mediterranean mountainous catchment (Ribera Salada, 224 km2; NE Iberian Peninsula) during three consecutive years (2005–2008). Dynamics were analysed based on: (i) rainfall, runoff and suspended sediment data at annual, seasonal and monthly scales, and (ii) the hysteresis patterns observed in discharge-suspended sediment relations (Q-SSC) at monthly and flood scales. Hysteresis was characterised by means of a hysteresis index and the time delay between peaks in Q and SSC. Additionally, variables related to rainfall, runoff, sediment transport and periodicity were used to infer the main causes of hysteresis patterns observed at each temporal scale. The spatial distribution of precipitation was obtained from images of daily rainfall fields obtained from radar information. Sediment dynamics were controlled by antecedent conditions (precipitation), flood magnitude and sediment availability, which, in turn, depend on the inactivity period between floods and the annual cycles of sediment production-deposition-depletion in the catchment. Three main situations were observed: (a) in winter, sediment availability and hydro-sedimentary were both low; (b) in spring, sediments mainly came from channels and banks, and from well-connected slopes, and the hydro-sedimentary activity was high; finally (c) in summer and early autumn, the main source of sediment was agricultural fields, with hydrological and sedimentary activity moderate. Counter-clockwise hysteresis loops were most frequent Q-SSC. This pattern happens when sediment sources are located far from where sediment transport is measured. However, the clockwise hysteresis loop is the most efficient pattern in terms of sediment load, being controlled by the release of subsurface material caused by the break-up of the surface armour layer of the riverbed during larger flood events. Despite the high efficiency of clockwise events, the Ribera Salada catchment is characterised by a low level geomorphic activity related to the limited sediment availability in the channel and the banks, and overall, in the upstream slopes, placing it in the lower bound of sedimentary activity reported for catchments of the Mediterranean region.
PubDate: Tue, 15 Mar 2022 00:00:00 +000
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- Editorial: Geomorphology, Quaternary Geology and Geoarchaeology of the
Eastern Mediterranean, Part 2-
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Editorial: Geomorphology, Quaternary Geology and Geoarchaeology of the Eastern Mediterranean, Part 2Evelpidou, Niki; Karymbalis, Efthimios
Zeitschrift für Geomorphologie, (2022), p. 137 - 139
PubDate: Tue, 08 Feb 2022 00:00:00 +000
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- Long-term spatial and temporal shoreline changes of the Evinos River
delta, Gulf of Patras, Western Greece-
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Long-term spatial and temporal shoreline changes of the Evinos River delta, Gulf of Patras, Western GreeceKarymbalis, Efthimios; Gallousi, Christina; Cundy, Andrew; Tsanakas, Konstantinos; Gaki-Papanastassiou, Kalliopi; Tsodoulos, Ioannis; Batzakis, Dimitrios-Vasileios; Papanastassiou, Dimitrios; Liapis, Ioannis; Maroukian, Hampik
Zeitschrift für Geomorphologie, (2022), p. 141 - 155AbstractThis study deals with the long-term shoreline displacement of the Evinos River delta in Western Greece using various geospatial data sets from different sources. The comparison between the extracted coastlines allowed us to identify segments where the delta progrades and parts of the delta that are being eroded over the periods 1945–1969 and 1969–2015. Coastal area variations giving land losses or gains of the most active sectors of the delta associated with changes in shoreline position were calculated over the periods 1993–2002 and 2002–2018 using Landsat TM satellite images. The results showed that nearly 46% of the Evinos delta is in retreat. Erosion be attributed to human activitiesis essentially affecting the eastern deltaic shoreline with retreat rates commonly reaching up to 8 m/yr in places. In addition, the area of the artificially closed pre-1959 mouth of the river has retreated at an average rate of 14 m/yr over the past 57 years. The old natural mouth of the river (depicted in a map of 1885) at Akra Evinou (Cape Evinos) has retreated up to 350 m (5 m/yr) over the last 71 years. West of the active river mouth, mobile elongated features such as sand spits and barriers are formed by deposition of sediment produced by the erosion of the abandoned eastern delta coastline. The main natural cause of the long-term Evinos River delta coastline displacements is the nearshore current activity induced by the dominant incoming wind generated waves. Land loss of the active part of the delta (at rates up to 16,797 m2/yr) has been recorded over the period 2002–2018. This generalized erosion can be attributed to human activities that include: the construction of a dam in the upper reaches of the catchment that dramatically decreased the suspended sediment concentrations in the delta, the extensive sand and gravel mining in the distributary channel, and a small earth dam constructed at the apex of the delta for irrigation purposes.
PubDate: Tue, 08 Feb 2022 00:00:00 +000
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- Sediment transport patterns and beach morphodynamics in the semi-enclosed
bay of Platis Gialos, Sifnos Island, Aegean Sea-
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Sediment transport patterns and beach morphodynamics in the semi-enclosed bay of Platis Gialos, Sifnos Island, Aegean SeaPetropoulos, Alexandros; Evelpidou, Niki; Kapsimalis, Vasilis; Anagnostou, Christos; Karkani, Anna
Zeitschrift für Geomorphologie, (2022), p. 157 - 182AbstractPocket beaches are a large part of the Greek coastline, with strong touristic, economic and natural interest. Their morphological characteristics and wave forcing are the main factors influencing their evolution, while the most commonly observed dynamic is beach rotation due to prevailing wave direction. Human activities and climate change call for a better management for these areas, necessitating, therefore, the identification of coastal geomorphodynamic processes. This paper focuses on the geomorphological and sedimentological dynamic processes of Platis Gialos Bay (Sifnos), which have given rise to the present setting. Beach orientation, slope, length, geology, Posidonia Oceanica, degree of embayment, sedimentology and closure are some parameters that must be considered to calculate the morphodynamic and stability indicators that prevail at the beach. Wave exposure forcing conditions, longshore – rip current direction, are also hydrodynamic processes to be determined, as they play a significant role in sediment transport. A number of methodologies took place in order to determine the level of disturbance of this dynamic equilibrium, which included morphological mapping, sedimentary classification, shoreline displacement/evolution monitoring, hydrodynamic and sedimentary modelling. The exposure of the coast to the southern waves, the reduced sediment supply from the local fluvial network, human activities and the construction of the fishing shelter have led the area to a continuous erosion and coastline retreat in its western and central part, in contrast to the eastern part, where there is a continuous deposition reflected by coastal accretion and the formation of a shallow environment.
PubDate: Tue, 08 Feb 2022 00:00:00 +000
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- Assessment of the sensitivity of Zakynthos Island (Ionian Sea, Western
Greece) to climate change-induced coastal hazards-
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Assessment of the sensitivity of Zakynthos Island (Ionian Sea, Western Greece) to climate change-induced coastal hazardsZampazas, Georgios; Karymbalis, Efthimios; Chalkias, Christos
Zeitschrift für Geomorphologie, (2022), p. 183 - 200AbstractLow-lying coastal areas around the world are threatened by climate change-induced hazards such as long-term mean sea-level rise and extreme sea-level events. The eustatic sea-level is rising rapidly due to global warming, whereas storm surges are expected to become more frequent and intense, which necessitate the identification and protection of sensitive sections of coastline. This paper deals with the classification of the coasts of Zakynthos Island, located in the Ionian Sea, according to their sensitivity to both coastal erosion and flooding, caused by climate change-induced hazards, with the assessment of the Coastal Sensitivity Index (CSI). CSI allows six physical variables to be related in a quantifiable manner. The variables include geology-geomorphology, coastal slope, rate of long-term shoreline erosion or accretion, relative sea-level change rate, mean wave height and mean tidal range. The produced CSI map for the studied coastline indicates that nearly 14.1 km, (corresponding to 7.4% of the entire coastline of the island) is characterized as highly and very highly sensitive primarily due to the low regional coastal slope and the presence of highly erodible sandy and coble beaches. The coasts of high and very high CSI values host socio-economically important land uses (discontinuous urban areas, touristically developed beaches, sport and leisure facilities and agricultural activities). Furthermore, about 25% of the coastline of the Zakynthos Natura 2000 protected area is highly and very highly sensitive to climate change exacerbated coastal hazards.
PubDate: Tue, 08 Feb 2022 00:00:00 +000
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