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Geosciences, Volume 10, Issue 8 (August 2020) – 47 articles

Cover Story (view full-size image): The ancient Albojaira (in Arab: Al Bujaira) Lake within the Almanzora Canyon disappeared during the 1863 Huércal-Overa Earthquake (SE Spain), suggesting an intensity of VIII-IX ESI-07. The lake was located within an abandoned meander of the Almanzora River (terrace +20 m) at the site named Los Oribes. The lake was emptied during the earthquake because of large ground-cracking in the ancient lake ground. Only the three permanent water bodies known as the “Ojos de Mar” (Sea Eyes) prevailed, but also emptied during subsequent seismic series. Ground photo kindly provided by Dr. Martin Stokes (University of Plymouth). View this paper
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Article
Yield Erosion Sediment (YES): A PyQGIS Plug-In for the Sediments Production Calculation Based on the Erosion Potential Method
Geosciences 2020, 10(8), 324; https://doi.org/10.3390/geosciences10080324 - 18 Aug 2020
Viewed by 1192
Abstract
The Erosion Potential Method is a model for qualifying the erosion severity and estimating the total annual sediment yield of a catchment. The method includes a diverse set of equations, which are influenced by different factors such as geology, morphology, climate and soil [...] Read more.
The Erosion Potential Method is a model for qualifying the erosion severity and estimating the total annual sediment yield of a catchment. The method includes a diverse set of equations, which are influenced by different factors such as geology, morphology, climate and soil use. This study describes a PyQGIS YES plug-in, which allows a semiautomatized use of the Erosion Potential Method in Geographic Information System (GIS) environment. In detail, we developed a plug-in using Python programming language that is made up of a series of operations allowing one to estimate sediment production through a wizard procedure. The first stage consists of data preprocessing and involves: (i) loading of the layers (e.g., geological map); (ii) spatial selection of the catchment area; (iii) elaboration of loaded layers (e.g., clipping). During the second stage, the user assigns a relative coefficient to each factor either by selecting a preloaded value from bibliographic sources or by inserting a value inferred from field observations and data. The third stage includes the addition of rainfall and temperature values loaded as: average values, point shapefiles (the plug-in calculates the average monthly values) or tables (the plug-in creates the linear regression depending on altitude). During the final stage, the plug-in executes the equation of EPM Model obtaining the sediment yield value at basin scale. Additionally, the user can use the “squared cell” method choosing the appropriate option in the setting dialogue of the plug-in. This method divides the catchment area in a regularly-spaced grid which allows one to carry out the distribution map of the sediment production during the final stage. Full article
(This article belongs to the Section Natural Hazards)
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Article
Analysis of the Influence of Structural Geology on the Massive Seismic Slope Failure Potential Supported by Numerical Modelling
Geosciences 2020, 10(8), 323; https://doi.org/10.3390/geosciences10080323 - 18 Aug 2020
Cited by 1 | Viewed by 873
Abstract
The stability of rock slopes is often guided significantly by the structural geology of the rocks composing the slope. In this work, we analysed the influences of structural characteristics, and of their seismic responses, on large and deep-seated rock slope failure development. The [...] Read more.
The stability of rock slopes is often guided significantly by the structural geology of the rocks composing the slope. In this work, we analysed the influences of structural characteristics, and of their seismic responses, on large and deep-seated rock slope failure development. The study was focused on the Tamins and Fernpass rockslides in the European Alps and on the Balta and Eagle’s Lake rockslides in the southeastern Carpathians. These case studies were compared with catastrophic rock slope failures with ascertained or very likely seismic origin in the Tien Shan Mountains. The main goals was to identify indicators for seismically-induced rock slope failures based on the source zone rock structures and failure scar geometry. We present examples of failures in anti-dip slopes and along-strike rock structures that were potentially (or partially) caused by seismic triggering, and we also considered a series of mixed structural types, which are more difficult to interpret conclusively. Our morpho-structural study was supported by distinct element numerical modelling that showed that seismic shaking typically induces deep-seated deformation in initially “stable” rock slopes. In addition, for failures partially triggered by dynamic shaking, these studies can help identify the contribution of the seismic factor to slope instability. The identification of the partial seismic origin on the basis of the dynamic response of rock structures can be particularly interesting for case histories in less seismically active mountain regions (in comparison with the Andes, Tien Shan, Pamirs), such as in the European Alps and the Carpathian Mountains. Full article
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Article
Open-Source MASW Inversion Tool Aimed at Shear Wave Velocity Profiling for Soil Site Explorations
Geosciences 2020, 10(8), 322; https://doi.org/10.3390/geosciences10080322 - 17 Aug 2020
Cited by 1 | Viewed by 1175
Abstract
The shear wave velocity profile is of primary interest for geological characterization of soil sites and elucidation of near-surface structures. Multichannel Analysis of Surface Waves (MASW) is a seismic exploration method for determination of near-surface shear wave velocity profiles by analyzing Rayleigh wave [...] Read more.
The shear wave velocity profile is of primary interest for geological characterization of soil sites and elucidation of near-surface structures. Multichannel Analysis of Surface Waves (MASW) is a seismic exploration method for determination of near-surface shear wave velocity profiles by analyzing Rayleigh wave propagation over a wide range of wavelengths. The inverse problem faced during the application of MASW involves finding one or more layered soil models whose theoretical dispersion curves match the observed dispersion characteristics. A set of open-source MATLAB-based tools for acquiring and analyzing MASW field data, MASWaves, has been under development in recent years. In this paper, a new tool, using an efficient Monte Carlo search technique, is introduced to conduct the inversion analysis in order to provide the shear wave velocity profile. The performance and applicability of the inversion scheme is demonstrated with synthetic datasets and field data acquired at a well-characterized geotechnical research site. Full article
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Article
Automated Land Cover Change Detection and Forest Succession Monitoring Using LiDAR Point Clouds and GIS Analyses
Geosciences 2020, 10(8), 321; https://doi.org/10.3390/geosciences10080321 - 17 Aug 2020
Cited by 4 | Viewed by 845
Abstract
This paper investigates the possibility of applying light detection and ranging (LiDAR) point clouds and geographic information system (GIS) analyses for land use and land cover (LULC) change detection, mainly with a view to monitoring uncontrolled forest succession occurring on postagricultural lands. The [...] Read more.
This paper investigates the possibility of applying light detection and ranging (LiDAR) point clouds and geographic information system (GIS) analyses for land use and land cover (LULC) change detection, mainly with a view to monitoring uncontrolled forest succession occurring on postagricultural lands. The research was conducted in a part of the administrative district of Milicz (in the central-west area of Poland). The areas of interest were parcels in which agricultural use has been abandoned and forest succession processes have progressed. The airborne laser scanning (ALS) data (acquired in 2007, 2012, and 2015) revealed detailed changes in land cover as a result of the progression in the forest succession process. Using the ALS data, the LULC changes and the progress of secondary forest succession are shown, and the vegetation parameters (LiDAR metrics) are presented. Full article
(This article belongs to the Special Issue A GIS Spatial Analysis Model for Land Use Change)
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Article
Laboratory and Physical Prototype Tests for the Investigation of Hydraulic Hysteresis of Pyroclastic Soils
Geosciences 2020, 10(8), 320; https://doi.org/10.3390/geosciences10080320 - 17 Aug 2020
Cited by 1 | Viewed by 663
Abstract
Proper soil water retention curves (SWRCs) are necessary for a fair analysis of groundwater flow in unsaturated slopes. The question is whether hydraulic parameters operating in situ can be reliably determined from laboratory tests or physical prototype models in order to interpret and [...] Read more.
Proper soil water retention curves (SWRCs) are necessary for a fair analysis of groundwater flow in unsaturated slopes. The question is whether hydraulic parameters operating in situ can be reliably determined from laboratory tests or physical prototype models in order to interpret and predict soil water distributions in the field. In this paper, some results obtained by tests at different scales (testing on laboratory specimens and a physical prototype) are presented to explore the hydraulic behavior of pyroclastic soils. A theoretical interpretation of the observed behavior in the laboratory and using a physical prototype is proposed by adopting the hysteretic model of Lenhard and Parker. For each tested soil, the main hysteretic loop determined by interpreting experimental tests (at laboratory and prototype scales) overlaps with paths detected by coupling the field measurements of matric suction and water content collected at the site at the same depth. From these results, the physical prototype (medium scale) and the soil specimen (small scale) seem to be acceptable for determinations of SWRC, provided that the air entrapment value is well known. Full article
(This article belongs to the Special Issue Innovative Strategies for Sustainable Mitigation of Landslide Risk)
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Article
Integrated Morpho-Bathymetric, Seismic-Stratigraphic, and Sedimentological Data on the Dohrn Canyon (Naples Bay, Southern Tyrrhenian Sea): Relationships with Volcanism and Tectonics
Geosciences 2020, 10(8), 319; https://doi.org/10.3390/geosciences10080319 - 17 Aug 2020
Viewed by 1057
Abstract
Submarine canyons are geomorphologic lineaments engraving the slope/outer shelf of continental margins. These features are often associated with significant geologic hazard when they develop close to densely populated coastal zones. The seafloor of Naples Bay is deeply cut by two incisions characterized by [...] Read more.
Submarine canyons are geomorphologic lineaments engraving the slope/outer shelf of continental margins. These features are often associated with significant geologic hazard when they develop close to densely populated coastal zones. The seafloor of Naples Bay is deeply cut by two incisions characterized by a dense network of gullies, namely the Dohrn and Magnaghi canyons, which develop from the shelf break of the Campania margin, down to the peripheral rise of the Eastern Tyrrhenian bathyal plain. Seismic-stratigraphic interpretation of multichannel seismic reflection profiles has shown that quaternary tectonics and recent to active volcanism have exerted a significant control on the morphological evolution and source-to sink depositional processes of the Dohrn and Magnaghi submarine canyons. The Dohrn canyon is characterized by relatively steep walls hundreds of meters high, which incise a Middle-Late Pleistocene prograding wedge, formed by clastic and volcaniclastic deposits associated with the paleo-Sarno river system during the Mid-Late Pleistocene. The formation of the Dohrn canyon predates the onset of the volcanic eruption of the Neapolitan Yellow Tuff (NYT), an ignimbrite deposit of ca. 15 ka that represents the bedrock on which the town of Napoli is built. Integrated stratigraphic analysis of high-resolution seismic profiles and marine gravity core data (C74_12) collected along the flanks of the eastern bifurcation of the head of Dohrn Canyon suggests that depositional processes along the canyon flanks are dominated by gravity flows (e.g., fine-grained turbidites, debris flows) and sediment mass transport associated with slope instability and failure. Full article
(This article belongs to the Section Geophysics)
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Article
Impact of Extreme Weather Events on Aboveground Net Primary Productivity and Sheep Production in the Magellan Region, Southernmost Chilean Patagonia
Geosciences 2020, 10(8), 318; https://doi.org/10.3390/geosciences10080318 - 16 Aug 2020
Cited by 1 | Viewed by 1114
Abstract
Spatio-temporal patterns of climatic variability have effects on the environmental conditions of a given land territory and consequently determine the evolution of its productive activities. One of the most direct ways to evaluate this relationship is to measure the condition of the vegetation [...] Read more.
Spatio-temporal patterns of climatic variability have effects on the environmental conditions of a given land territory and consequently determine the evolution of its productive activities. One of the most direct ways to evaluate this relationship is to measure the condition of the vegetation cover and land-use information. In southernmost South America there is a limited number of long-term studies on these matters, an incomplete network of weather stations and almost no database on ecosystems productivity. In the present work, we characterized the climate variability of the Magellan Region, southernmost Chilean Patagonia, for the last 34 years, studying key variables associated with one of its main economic sectors, sheep production, and evaluating the effect of extreme weather events on ecosystem productivity and sheep production. Our results show a marked multi-decadal character of the climatic variables, with a trend to more arid conditions for the last 8 years, together with an increase in the frequency of extreme weather events. Significant percentages of aboveground net primary productivity (ANPP) variance is explained by high precipitation, mesic temperatures, and low evapotranspiration. These conditions are, however, spatially distributed in the transition zone between deciduous forests and steppe and do not represent a general pattern for the entire region. Strong precipitation and wind velocity negatively affect lamb survival, while temperature and ANPP are positively correlated. The impact of extreme weather events on ANP and sheep production (SP) was in most of the cases significantly negative, with the exception of maximum temperature that correlated with an increase of ANPP, and droughts that showed a non-significant negative trend in ANPP. The examination of these relationships is urgent under the current scenario of climate change with the acceleration of the environmental trends here detected. Full article
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Article
Vegetation and Fluvial Geomorphology Dynamics after an Urban Fire
Geosciences 2020, 10(8), 317; https://doi.org/10.3390/geosciences10080317 - 16 Aug 2020
Viewed by 799
Abstract
The goal of this research was to characterize the impact of invasive riparian vegetation on burn severity patterns and fluvial topographic change in an urban Mediterranean riverine system (Med-sys) after fire in San Diego, California. We assessed standard post-fire metrics under urban conditions [...] Read more.
The goal of this research was to characterize the impact of invasive riparian vegetation on burn severity patterns and fluvial topographic change in an urban Mediterranean riverine system (Med-sys) after fire in San Diego, California. We assessed standard post-fire metrics under urban conditions with non-native vegetation and utilized field observations to quantify vegetation and fluvial geomorphic processes. Field observations noted both high vegetation loss in the riparian area and rapidly resprouting invasive grass species such as Arundo donax (Giant Reed) after fire. Satellite-based metrics that represent vegetation biomass underestimated the initial green canopy loss, as did volumetric data derived from three-dimensional terrestrial laser scanning data. Field measurements were limited to a small sample size but demonstrated that the absolute maximum topographic changes were highest in stands of Arundo donax (0.18 to 0.67 m). This work is the first quantification of geomorphic alterations promoted by non-native vegetation after fire and highlights potential grass–fire feedbacks that can contribute to geomorphic disruption. Our results support the need for ground-truthing or higher resolution when using standard satellite-based indices to assess post-fire conditions in urban open spaces, especially when productive invasive vegetation are present, and they also emphasize restoring urban waterways to native vegetation conditions. Full article
(This article belongs to the Special Issue Humans in the Earth System)
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Article
Reconstruction as a Long-Term Process. Memory, Experiences and Cultural Heritage in the Irpinia Post-Earthquake (November 23, 1980)
Geosciences 2020, 10(8), 316; https://doi.org/10.3390/geosciences10080316 - 15 Aug 2020
Cited by 3 | Viewed by 1108
Abstract
Reconstruction after an earthquake is often seen as a material issue, which concerns “objects” such as houses, roofs, and streets. This point of view is supported by the mass media showing the work progress in the disaster areas, especially in conjunction with anniversaries. [...] Read more.
Reconstruction after an earthquake is often seen as a material issue, which concerns “objects” such as houses, roofs, and streets. This point of view is supported by the mass media showing the work progress in the disaster areas, especially in conjunction with anniversaries. Rather, we should consider reconstruction as a complex social process in which cultural backgrounds, expectations, and ideas of the future come into play, without neglecting geological, historical, legislative, economic, and political factors. Combining oral history sources and archival records, the article shows the paths taken by two small towns among the most affected by the earthquake of 23rd November 1980 (Mw 6.9). These towns have made opposite reconstruction choices (in situ and ex novo) representing two classical and different ways in which human societies can face their past and think their own future. A careful analysis of these forty-year experiences, with a special focus on cultural heritage, provides useful indications for post-disaster reconstructions in which more attention to the process, and not just to the final product, should be paid. Full article
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Article
Probabilistic-Based Assessment of Liquefaction-Induced Damage with Analytical Fragility Curves
Geosciences 2020, 10(8), 315; https://doi.org/10.3390/geosciences10080315 - 15 Aug 2020
Cited by 3 | Viewed by 683
Abstract
Soil liquefaction may cause severe damages to structures mainly in terms of lateral spread and settlements, as documented during historical earthquakes. Liquefaction-potential (LP) estimation has become an important issue in seismic assessment, and this paper aims to propose a new methodology based on [...] Read more.
Soil liquefaction may cause severe damages to structures mainly in terms of lateral spread and settlements, as documented during historical earthquakes. Liquefaction-potential (LP) estimation has become an important issue in seismic assessment, and this paper aims to propose a new methodology based on fragility curves. LP curves were developed and applied to two case studies performed with 3D numerical models applying Opensees. Nonlinear hysteretic materials and advanced plasticity models were used to reproduce the high nonlinear mechanisms of liquefaction, such as strong dilation tendency and cyclic shear behaviour. LP curves were applied to compare the results of the performed free field (FF) and soil–structure interaction (SSI) case studies. Full article
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Article
Understanding Wetlands Stratigraphy: Geophysics and Soil Parameters for Investigating Ancient Basin Development at Lake Duvensee
Geosciences 2020, 10(8), 314; https://doi.org/10.3390/geosciences10080314 - 14 Aug 2020
Cited by 3 | Viewed by 1184
Abstract
We present a case study of a bog showing how an integrated approach of multi-method geophysical sounding and local soil sampling can be used to identify, differentiate, and map organic sediments. Our study is based on ground-penetrating radar (GPR), electrical resistivity tomography (ERT) [...] Read more.
We present a case study of a bog showing how an integrated approach of multi-method geophysical sounding and local soil sampling can be used to identify, differentiate, and map organic sediments. Our study is based on ground-penetrating radar (GPR), electrical resistivity tomography (ERT) and shear-wave seismic (SH seismic) profiling applied to sediments of the former Lake Duvensee (northern Germany), nowadays a bog. This is a well-known locality for remains from the Mesolithic hunter-gatherers’ occupation that has been attracting archaeological and geoarchaeological research for100 years. The bog is embedded in low conductive glacial sand and is characterized by layers of different gyttja sediments (detritus and calcareous). The present study was conducted in order to identify the bog morphology and the thickness of the peat body and lake sediments, in order to understand the basin evolution. To validate the geophysical results, derived from surface measurements, drilling, soil analyses as well as borehole guided wave analysis of electromagnetic waves and Direct-Push (DP-EC) have been carried out and used for comparison. It turned out that each method can distinguish between sediments that differ in grain size, particularly between peat, lake sediments (gyttjas and mud) and basal glacial sand deposits. GPR is even able to separate between strongly and weakly decomposed peat layers, which is also clear considering resistivity variations in the ERT computation. From the association between geophysical properties and sediment analysis (e.g., water content and organic matter) different gyttjas were distinguished (coarse and fine) and seismic velocity was correlated to bulk density. Moreover, GPR and SH-wave seismics present different resolutions, confirming that the latter allows measurements, which are more focused on determining the extension of basal sand deposits, the depth of which is difficult to reach with GPR. Representative values of electrical resistivity, dielectric permittivity, and shear wave velocity have been determined for each sediment type and are therefore available to complete the investigation of wetland environments. Fine grained lake sediments were difficult to differentiate by the applied methods. This could be a result of high ionic concentration within the permanent groundwater body, partly masking the sediment properties. Full article
(This article belongs to the Section Geophysics)
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Article
Sedimentation Patterns of Multiple Finnish Lakes Reveal the Main Environmental Stressors and the Role of Peat Extraction in Lake Sedimentation
Geosciences 2020, 10(8), 313; https://doi.org/10.3390/geosciences10080313 - 13 Aug 2020
Viewed by 2103
Abstract
Human land-use activities, especially in the peatlands, are under consideration as the mitigation and lowering of CO2 emissions from land-use practices is needed to address climate change. In Finland, approximately one third of the land surface is covered by peatlands, and around [...] Read more.
Human land-use activities, especially in the peatlands, are under consideration as the mitigation and lowering of CO2 emissions from land-use practices is needed to address climate change. In Finland, approximately one third of the land surface is covered by peatlands, and around 50% of peatlands are ditched for forestry. Another 3% of peatlands are used for agriculture and approximately 1% for peat extraction. The effects of these different land-use practices, including changes in sediment depositional rates and sediment quality, need to be identified. This study analyzed 51 lakes that were subdivided into two groups: (1) a group of impacted lakes in which peat was recently extracted from the catchments and (2) a reference group consisting of lakes where peat had not been extracted from the basin, but in which other land-use activities had occurred. The overall aim of the study was to investigate if peat extraction caused excessive delivery and deposition of dry and organic matter in lakes that are located in their immediate downstream catchment areas. Differences in sediment accumulation were defined by comparing the overall sediment thickness and recent (post 1986) sedimentation levels to identify if there were differences in the sediment chemical composition or rate of organic matter deposition between groups and to identify possible land-use stressors that could explain the possible differences in sediment chemical assemblages or sedimentation rates. The results show moderate (cm scale) sedimentation rates in both impacted and reference lakes after 1986, while sediment chemical assemblages indicated the erosion and input of mineral soils to all of the studied lakes, rather than the input of organic materials. No statistically significant correlations were observed between selected environmental variables and the recent accumulation rates of carbon and dry matter. Moreover, significant changes in the stressors potentially affecting the chemical assemblages of pre- and post-disturbance sediments were not observed. Full article
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Article
Influence of Climate Changes on the State of Water Resources in Poland and Their Usage
Geosciences 2020, 10(8), 312; https://doi.org/10.3390/geosciences10080312 - 13 Aug 2020
Cited by 8 | Viewed by 1129
Abstract
The study aims to estimate the amount of available renewable water resources in Poland in the years 1999–2018 and the extent of their use by various sectors of the national economy at the national and regional levels. In the study period, the selected [...] Read more.
The study aims to estimate the amount of available renewable water resources in Poland in the years 1999–2018 and the extent of their use by various sectors of the national economy at the national and regional levels. In the study period, the selected meteorological elements were found to have changed, resulting in a decrease in the flows of the two largest rivers in Poland: the Vistula and the Oder. The outflow of the Vistula and Odra basins determines the size of Poland’s water resources. Poland is classified as a country of low water resources, as evidenced by the per capita amount of surface water, which in the years 1999–2018 was 1566 m3/capita. Water consumption to meet the needs of the economy and the population was stable, and averaged 283 m3/capita in this period. The analysis of water consumption by region showed that the areas with the lowest annual precipitation consume significant amounts of water for economic purposes, which may limit or destabilise socio-economic development in the region in future. Based on the difference between the amount of precipitation and water losses in the form of evaporation and water abstraction for economic purposes, maps were drawn up showing the deficit of surface water in a dry year. During periods of surface water scarcity, groundwater uptake increases. An area particularly exposed to water scarcity is central Poland. Full article
(This article belongs to the Special Issue 2020: A 10 Years Journey-Advances in Geosciences)
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Article
Submagmatic to Solid-State Deformation Microstructures Recorded in Cooling Granitoids during Exhumation of Late-Variscan Crust in North-Eastern Sicily
Geosciences 2020, 10(8), 311; https://doi.org/10.3390/geosciences10080311 - 13 Aug 2020
Cited by 1 | Viewed by 734
Abstract
Late-Variscan granitoid rocks of trondhjemitic and granitic composition, intruded in migmatitic paragneisses in the north-eastern Peloritani Mountains (southern Italy) at ~310 Ma and ~300 Ma, respectively, exhibit a range of deformation microstructures developed under a shear regime at decreasing temperatures. Non-coaxial deformation is [...] Read more.
Late-Variscan granitoid rocks of trondhjemitic and granitic composition, intruded in migmatitic paragneisses in the north-eastern Peloritani Mountains (southern Italy) at ~310 Ma and ~300 Ma, respectively, exhibit a range of deformation microstructures developed under a shear regime at decreasing temperatures. Non-coaxial deformation is documented by sigmoidal feldspar porphyroclasts, mica fish, and asymmetric boudins affecting tiny andalusite crystals. Late-Variscan shearing during granitoid cooling is constrained by largely represented chessboard patterns in quartz and, especially, submagmatic fractures in plagioclase, indicating deformation at high-temperature conditions (T > 650 °C), in the presence of melt. Submagmatic deformation was extensively superseded by deformation at lower temperatures. Examples of solid state-high temperature deformation-related microstructures (T > 450 °C) include feldspar bulging, quartz grain boundary migration, and subgrain rotation recrystallization. Finally, low temperature subsolidus microstructures (T < 450 °C) consist of quartz bulging, mica kinks, and feldspar twinning and bending. A complete sequence of deformation, operating from submagmatic to low-temperature subsolidus conditions is recorded in both the older and younger granitoids, suggesting a duration of ~20 Ma for shear zone activity during post-collisional exhumation of the Variscan middle crust in southernmost Italy. Full article
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Article
Investigating the Behavior of an Onshore Wall and Trench Combination Ahead of a Tsunami-Like Wave
Geosciences 2020, 10(8), 310; https://doi.org/10.3390/geosciences10080310 - 13 Aug 2020
Cited by 1 | Viewed by 743
Abstract
This study investigates a wall and trench combination to identify its benefits as a defense measure against an overtopping tsunami-like wave. The study focuses on several arrangements and geometries of a wall and trench combined structural system, located on the shoreline. The structural [...] Read more.
This study investigates a wall and trench combination to identify its benefits as a defense measure against an overtopping tsunami-like wave. The study focuses on several arrangements and geometries of a wall and trench combined structural system, located on the shoreline. The structural system is assessed via a numerical model, which is initially calibrated by physical experiments of tsunami-like wave transformations. A dam break event is used to model a tsunami-like wave interaction with the structures. Resulted wave properties are investigated to identify the behavior of the structural system from the viewpoint of structure geometry and configuration. The results of the study clearly show that the proposed structure combination can effectively reduce the impact of tsunami-like waves, better than a single sea wall defense system. This is achieved by reducing both wave run-up and wave induced current velocities at the lee side of the structure. Full article
(This article belongs to the Special Issue Interdisciplinary Geosciences Perspectives of Tsunami Volume 3)
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Article
Mapping Landslide Prediction through a GIS-Based Model: A Case Study in a Catchment in Southern Italy
Geosciences 2020, 10(8), 309; https://doi.org/10.3390/geosciences10080309 - 12 Aug 2020
Cited by 4 | Viewed by 1243
Abstract
Shallow landslides are an increasing concern in Italy and worldwide because of the frequent association with vegetation management. As vegetation cover plays a fundamental role in slope stability, we developed a GIS-based model to evaluate the influence of plant roots on slope safety, [...] Read more.
Shallow landslides are an increasing concern in Italy and worldwide because of the frequent association with vegetation management. As vegetation cover plays a fundamental role in slope stability, we developed a GIS-based model to evaluate the influence of plant roots on slope safety, and also included a landslide susceptibility map. The GIS-based model, 4SLIDE, is a physically based predictor for shallow landslides that combines geological, topographical, and hydrogeological data. The 4SLIDE combines the infinite slope model, TOPMODEL (for the estimation of the saturated water level), and a vegetation root strength model, which facilitates prediction of locations that are more susceptible for shallow landslides as a function of forest cover. The aim is to define the spatial distribution of Factor of Safety (FS) in steep-forested areas. The GIS-based model 4SLIDE was tested in a forest mountain watershed located in the Sila Greca (Cosenza, Calabria, South Italy) where almost 93% of the area is covered by forest. The sensitive ROC analysis (Receiver Operating Characteristic) indicates that the model has good predictive capability in identifying the areas sensitive to shallow landslides. The localization of areas at risk of landslides plays an important role in land management activities because landslides are among the most costly and dangerous hazards. Full article
(This article belongs to the Special Issue Innovative Strategies for Sustainable Mitigation of Landslide Risk)
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Article
Analysis of Fragmentation of Rock Blocks from Real-Scale Tests
Geosciences 2020, 10(8), 308; https://doi.org/10.3390/geosciences10080308 - 11 Aug 2020
Cited by 3 | Viewed by 987
Abstract
Real-scale fragmentation tests provide high quality data in order to study the fragmentation pattern of rock blocks. In the tests carried out, the initial rock mass, in terms of both volume and shape, was reconstructed by means of 3D photogrammetry. The fragments size [...] Read more.
Real-scale fragmentation tests provide high quality data in order to study the fragmentation pattern of rock blocks. In the tests carried out, the initial rock mass, in terms of both volume and shape, was reconstructed by means of 3D photogrammetry. The fragments size distribution of the bocks tested was measured by hand using a tape. The drop tests were performed in four different sites, releasing a total of 124 blocks and measuring 2907 fragments. The obtained fragment size distributions may be well fitted using power laws. The survival rate (Sr), which is the proportion of remaining block shows a wide range of values. Observing the fragment distribution, two parameters are needed to characterize the fragmentation: the number of fragments produced and Sr. The intensity of the fragmentation is expressed by the exponent of the fitted power laws. Although the results are highly variable and show a stochastic behavior of the fragmentation, we have identified different patterns that reflect some local test conditions. Full article
(This article belongs to the Special Issue Rockfall Hazard)
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Article
Combined Use of 3D Metric Survey and GPR for the Diagnosis of the Trapezophoros with Two Griffins Attacking a Doe of Ascoli Satriano (Foggia, Italy)
Geosciences 2020, 10(8), 307; https://doi.org/10.3390/geosciences10080307 - 09 Aug 2020
Viewed by 773
Abstract
Protection and conservation are not feasible without a deeper knowledge of the cultural heritage of the subject of intervention. A careful analysis of documentation, a detailed visual inspection of surfaces, and a systematic diagnosis of the inner properties are the basis for planning [...] Read more.
Protection and conservation are not feasible without a deeper knowledge of the cultural heritage of the subject of intervention. A careful analysis of documentation, a detailed visual inspection of surfaces, and a systematic diagnosis of the inner properties are the basis for planning preventive strategies of restoration. Digital noninvasive techniques represent an advantageous tool with useful outputs to estimate the state of health of cultural heritage in order to minimize the progress of degradation. This paper deals with a 3D metric survey through photogrammetry and ground-penetrating radar (GPR) tests applied to the study of the trapezophoros with two griffins attacking a doe of Ascoli Satriano, a masterpiece of ancient art that needs to be protected. This work provided information on both visible and hidden defects, such as numerous cracks that affect the sculpture. Full article
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Review
Identifying Gaps in the Investigation of the Vredefort Granophyre Dikes: A Systematic Literature Review
Geosciences 2020, 10(8), 306; https://doi.org/10.3390/geosciences10080306 - 09 Aug 2020
Cited by 1 | Viewed by 885
Abstract
The Vredefort impact structure is among the oldest and largest impact structures preserved on Earth. An understanding of its key features can serve as a guide for learning about the development of basin-sized impact structures on Earth and other planetary bodies. One of [...] Read more.
The Vredefort impact structure is among the oldest and largest impact structures preserved on Earth. An understanding of its key features can serve as a guide for learning about the development of basin-sized impact structures on Earth and other planetary bodies. One of these features is the so-called Vredefort granophyre dikes, which formed when molten material from the impact melt sheet was emplaced below the crater floor. The importance of these dikes has been recognized since the earliest studies of the Vredefort structure, nearly 100 years ago. The present study is a systematic literature review to determine the extent to which peer-reviewed scientific publications have generated unique data regarding the granophyre dikes and to investigate how scientific methods used to investigate the granophyre have changed over time. In total, 33 unique studies have been identified. Of those, more studies have been performed into the core-collar dikes than the core dikes. The majority of the studies have focused on field analyses, bulk geochemistry, and the studies of mineral components. The granophyre has long been recognized as a product of post-deformational processes and thus has been a target of age dating to constrain the minimum age of the impact event. In the last 25 years, studies of stable isotopes and shock deformation of minerals in lithic clasts within the dikes have taken place. A small number of geophysical studies relevant to the granophyre dikes have also been undertaken. Overall, there has been a relatively small number of studies on this important rock type, and the studies that have taken place tend to focus on two particular dikes. Several of the dikes have only been investigated by regional studies and have not been specifically targeted. The use of modern techniques has been lacking. More fieldwork, as well as geophysical, isotopic, microstructural studies, and application of novel techniques, are necessary for the granophyre dikes to be truly understood. Full article
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Article
Eurocode 7 and Rock Engineering Design: The Case of Rockfall Protection Barriers
Geosciences 2020, 10(8), 305; https://doi.org/10.3390/geosciences10080305 - 08 Aug 2020
Cited by 3 | Viewed by 806
Abstract
The Eurocode 7 or EC7 is the Reference Design Code (RDC) for geotechnical design including rock engineering design within the European Union (EU). Moreover, its principles have also been adopted by several other countries, becoming a key design standard for geotechnical engineering worldwide. [...] Read more.
The Eurocode 7 or EC7 is the Reference Design Code (RDC) for geotechnical design including rock engineering design within the European Union (EU). Moreover, its principles have also been adopted by several other countries, becoming a key design standard for geotechnical engineering worldwide. It is founded on limit state design (LSD) concepts, and the reliability of design is provided mainly by a semi-probabilistic method based on partial factors. The use of partial factors is currently an advantage, mainly for the simplicity in its applicability, and a limitation, especially concerning geotechnical designs. In fact, the application of partial factors to geotechnical design has proven to be difficult. In this paper, the authors focus on the way to apply EC7 principles to rock engineering design by analyzing the design of rockfall protection structures as an example. A real case of slope subjected to rockfall is reported to outline the peculiarity connected to rock engineering. The main findings are related to the complementarity of the reliability-based design (RBD) approach within EC7 principles and the possibility of overcoming the limitations of a partial factor approach to this type of engineering problem. Full article
(This article belongs to the Special Issue Rockfall Hazard)
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Article
Seismic Coda-Waves Imaging Based on Sensitivity Kernels Calculated Using an Heuristic Approach
Geosciences 2020, 10(8), 304; https://doi.org/10.3390/geosciences10080304 - 08 Aug 2020
Cited by 3 | Viewed by 938
Abstract
In this paper we review and discuss the seismic method based on the analysis of seismic coda waves used in the last 10 years by the present authors and/or their co-workers, to produce separate images of intrinsic- and scattering attenuation in zones of [...] Read more.
In this paper we review and discuss the seismic method based on the analysis of seismic coda waves used in the last 10 years by the present authors and/or their co-workers, to produce separate images of intrinsic- and scattering attenuation in zones of peculiar geological interest (mainly volcanoes). Such separate attenuation images are considered by the scientific community as complementary to those from ordinary velocity-tomography and useful to improve the geological interpretation in volcanoes and in tectonically active zones. In this review we only list but do not discuss the most significative papers showing the images obtained, as we are focused to review the method and not the interpretation of data analysis. For sake of completeness, we anyway show also a new analysis applied to data from Stromboli volcano. We thus first introduce the physical model describing the seismogram Energy Envelope (derived from the solution of the Energy Transport integral Equation) and discuss its asymptotic approximations (Diffusion- and Single-scattering model). Then, we describe a numerical method to heuristically calculate the Sensitivity Kernels for the propagation of the scattered waves in the assumption of isotropic scattering. We attribute to these Sensitivity Kernels the physical meaning of probability that for a single source-receiver couple the measured attenuation parameters can be associated with the space coordinates. Based on this definition, the attenuation image can be obtained mapping the estimated attenuation parameters onto the zone under study weighting with the Sensitivity Kernels. We further discuss how to estimate the uncertainties associated with the results and report the list of the papers describing the (separated) scattering- and intrinsic-attenuation structures investigated using this approach. Full article
(This article belongs to the Special Issue 2020: A 10 Years Journey-Advances in Geosciences)
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Article
Reappraisal of the 1863 Huércal-Overa Earthquake (Betic Cordillera, SE Spain) by the Analysis of ESI-07 Environmental Effects and Building Oriented Damage
Geosciences 2020, 10(8), 303; https://doi.org/10.3390/geosciences10080303 - 07 Aug 2020
Cited by 1 | Viewed by 984
Abstract
This work reviews the 1863 Huércal-Overa earthquake (VI-VII EMS) based on the environmental seismic intensity scale (ESI-07) and oriented archaeoseismological building damage. The performed analysis identifies 23 environmental effects (EEEs) and 11 archaeoseismological effects (EAEs), completing a total of 34 intensity data-points within [...] Read more.
This work reviews the 1863 Huércal-Overa earthquake (VI-VII EMS) based on the environmental seismic intensity scale (ESI-07) and oriented archaeoseismological building damage. The performed analysis identifies 23 environmental effects (EEEs) and 11 archaeoseismological effects (EAEs), completing a total of 34 intensity data-points within the intensity zone ≥ VI EMS. The new ESI intensity data quintuplicate the previous intensity data-points ≥ VI EMS (five localities) for this event. Sixteen of the identified EEEs indicate the occurrence of intensity VII-VIII within the Almanzora valley, south of Huércal-Overa, over an area of ca. 12–15 km2. Anomalies in water bodies, slope movements, hydrogeological anomalies, ground cracking, and other effects (gas emissions, tree shaking) are the more diagnostic EEEs—with one of them indicating a local maximum intensity of VIII-IX ESI-07 (Alboraija lake). Environmental earthquake damage of intensity ≥ VI covers an area of c. 100 km2, compatible with a VIII ESI intensity event. The spatial distribution of EEEs and EAEs indicates that the zone of Almanzora River Gorge, which was depopulated during the earthquake epoch, was the epicentral area, and compatible with seismotectonic data from active shallow blind thrusting beneath the Almagro Range. The use of ESI data in nearly unpopulated areas help to fill gaps between damaged localities (EMS data) multiplying intensity data-points, providing a better definition of the intensity zones and offering a geological basis to look for suspect seismic sources. Full article
(This article belongs to the Special Issue Earthquake Environmental Effects in the Historical and Recent Data)
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Article
An Approach to the Paleoceanographic Characteristics of the Sea-Surface at the Western Mediterranean (Balearic Area) during the Pliocene and Gelasian
Geosciences 2020, 10(8), 302; https://doi.org/10.3390/geosciences10080302 - 07 Aug 2020
Cited by 1 | Viewed by 707
Abstract
From the study of the planktonic foraminifer assemblages of the sediments of the Ocean Drilling Program (ODP)-Site 975 (Baleares), sea-surface temperature, seasonality and salinity for the Pliocene and Gelasian of the Western Mediterranean were estimated. The estimates were carried out by the modern [...] Read more.
From the study of the planktonic foraminifer assemblages of the sediments of the Ocean Drilling Program (ODP)-Site 975 (Baleares), sea-surface temperature, seasonality and salinity for the Pliocene and Gelasian of the Western Mediterranean were estimated. The estimates were carried out by the modern analog technique (MAT) using PaleoUma, a calibration dataset of 735 North-Atlantic and Mediterranean core-tops. In order to compare Pliocene–Gelasian and present-day analog assemblages, the necessary reduction of the taxonomic variables leads to statistically insignificant increases in estimation error, assessed on the calibration dataset itself. In addition, the correlation with δ18O results as an independent proxy, supports the use of MAT in order to establish the dominant paleoceanographic frameworks during the Pliocene and Gelasian. The SST curve shows an increase trend of the average value since the Early Zanclean (19.7 ± 1.8 °C) to the Late Piacenzian (20.9 ± 1.7 °C) and a decrease until the Late Gelasian (18.1 ± 1.4 °C). The seasonality offers permanently lower estimates than the current value (9.8 °C), reaching the closest values during the Late Gelasian (8.6 ± 0.8 °C). The salinity estimates are overall slightly lower during the Zanclean (36.7‰ ± 0.5‰) than today (37.3‰), whereas they reach up to more than 38.5‰, in the Early Piacenzian. The paleoceanographic frameworks deduced from the combination of the paleoceanographic parameters suggest that the current water-deficit regime in the Mediterranean was clearly predominant throughout the Pliocene and Gelasian. However, since the Piacenzian this regime alternates with stages of water surplus, which are especially frequent in the late Piacenzian. By the middle of the Early Gelasian the regime becomes more predominantly in deficit again. Full article
(This article belongs to the Special Issue Tectono-Sedimentary Evolution of Cenozoic Basins)
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Article
Late Miocene-Early Pliocene Out-of-Sequence Thrusting in the Southern Apennines (Italy)
Geosciences 2020, 10(8), 301; https://doi.org/10.3390/geosciences10080301 - 06 Aug 2020
Cited by 3 | Viewed by 1188
Abstract
We present a structural study on late Miocene-early Pliocene out-of-sequence thrusts affecting the southern Apennine orogenic belt. The analyzed structures are exposed in the Campania region (southern Italy). Here, thrusts bound the N-NE side of the carbonate ridges that form the regional mountain [...] Read more.
We present a structural study on late Miocene-early Pliocene out-of-sequence thrusts affecting the southern Apennine orogenic belt. The analyzed structures are exposed in the Campania region (southern Italy). Here, thrusts bound the N-NE side of the carbonate ridges that form the regional mountain backbone. In several outcrops, the Mesozoic carbonates are superposed onto the unconformable wedge-top basin deposits of the upper Miocene Castelvetere Group, providing constraints to the age of the activity of this thrusting event. Moreover, a 4-km-long N-S oriented electrical resistivity tomography profile, carried out along the Caserta mountains, sheds light on the structure of this thrust system in an area where it is not exposed. Further information was carried out from a tunnel excavation that allowed us to study some secondary fault splays. The kinematic analysis of out-of-sequence major and minor structures hosted both in the hanging wall (Apennine Platform carbonates) and footwall (Castelvetere Group deposits and Lagonegro-Molise Basin units) indicates the occurrence of two superposed shortening directions, about E-W and N-S, respectively. We associated these compressive structures to an out-of-sequence thrusting event defined by frontal thrusts verging to the east and lateral ramp thrusts verging to the north and south. We related the out-of-sequence thrusting episode to the positive inversion of inherited normal faults located in the Paleozoic basement. These envelopments thrust upward to crosscut the allochthonous wedge, including, in the western zone of the chain, the upper Miocene wedge-top basin deposits. Full article
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Article
Study of VCM Improved Soft Soil Properties Using Non-Destructive and Destructive Techniques
Geosciences 2020, 10(8), 300; https://doi.org/10.3390/geosciences10080300 - 06 Aug 2020
Viewed by 663
Abstract
In Bangkok, the demand for housing is extensively high due to the city growing rapidly, so some swampy areas are filled with soil. A Prefabricated Vertical Drain (PVD) with the Vacuum Consolidation Method (VCM) is required to make the soil applicable for construction. [...] Read more.
In Bangkok, the demand for housing is extensively high due to the city growing rapidly, so some swampy areas are filled with soil. A Prefabricated Vertical Drain (PVD) with the Vacuum Consolidation Method (VCM) is required to make the soil applicable for construction. However, it is difficult to monitor the soil strength during the process because the airtight sheet will be broken. This research aims to study the possibility of using the Spectral Analysis of Surface Waves (SASW) test to monitor the effectiveness of the VCM method and to study the development of shear-wave velocity over the consolidation period. Multiple instruments were installed on site, namely, vacuum gauges, settlement plates, and a piezometer, as well as a borehole to monitor the pump pressure, settlement, porewater pressure, and soil properties. Ten SASW tests were taken to measure the change in shear-wave velocity (Vs) over 7 months. The results showed an increment in the Vs along with increments in the settlement and undrained shear strength (Su), as well as a decrement in pore pressure during the consolidation period. The correlation between Vs and soil settlement was developed to predict the amount of settlement using Vs. These all indicated the potential of using the SASW method for soil improvement monitoring purposes. Full article
(This article belongs to the Section Geophysics)
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Review
Seismic Reflection Methods in Offshore Groundwater Research
Geosciences 2020, 10(8), 299; https://doi.org/10.3390/geosciences10080299 - 05 Aug 2020
Cited by 2 | Viewed by 1606
Abstract
There is growing evidence that passive margin sediments in offshore settings host large volumes of fresh and brackish water of meteoric origin in submarine sub-surface reservoirs. Marine geophysical methods, in particular seismic reflection data, can help characterize offshore hydrogeological systems and yet the [...] Read more.
There is growing evidence that passive margin sediments in offshore settings host large volumes of fresh and brackish water of meteoric origin in submarine sub-surface reservoirs. Marine geophysical methods, in particular seismic reflection data, can help characterize offshore hydrogeological systems and yet the existing global database of industrial basin wide surveys remains untapped in this context. In this paper we highlight the importance of these data in groundwater exploration, by reviewing existing studies that apply physical stratigraphy and morpho-structural interpretation techniques to provide important information on—reservoir (aquifer) properties and architecture, permeability barriers, paleo-continental environments, sea-level changes and shift of coastal facies through time and conduits for water flow. We then evaluate the scientific and applied relevance of such methodology within a holistic workflow for offshore groundwater research. Full article
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Article
Proposal of a System for Assessment of the Sustainability of Municipalities (Sasmu) Included in the Spanish Network of National Parks and Their Surroundings
Geosciences 2020, 10(8), 298; https://doi.org/10.3390/geosciences10080298 - 05 Aug 2020
Cited by 1 | Viewed by 879
Abstract
It is usually considered that Protected Areas (PAs) are an efficient tool for policies to conserve biodiversity. However, there is evidence that some pressures and threats arise from processes taking place both inside them and in their surroundings territories—habitat loss, changes in land [...] Read more.
It is usually considered that Protected Areas (PAs) are an efficient tool for policies to conserve biodiversity. However, there is evidence that some pressures and threats arise from processes taking place both inside them and in their surroundings territories—habitat loss, changes in land use, fragmentation of natural ecosystems. In this paper, we aim to test the hypothesis that municipalities located in the Socioeconomic Influence Zones (SIZs) of the fifteen National Parks (NPs) in Spain are more sustainable than those in their surroundings or, conversely, that the municipalities of their surroundings are more unsustainable. To measure their sustainability, we propose a system for assessment using fifteen indicators selected by experts. The methodology is based on the normalization of the data of each indicator, comparing them with a desirable target value defined in terms of sector policies and strategies. We then aggregate the indicators for each group in three indices that cover the classic dimensions of sustainability—environmental, economic and social. On a network scale, the results show that municipalities inside the SIZs are 1.594 points more sustainable environmentally, 0.108 economically and 0.068 socially than those of their surroundings. A system for assessment of the sustainability of municipalities (SASMU) may be a useful tool for NP managers, and for local and regional administrations, when setting priorities for policies, projects and compensation for regulatory restrictions related to NPs. Full article
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Article
Reinterpreting Models of Slope-Front Recharge in a Desert Basin
Geosciences 2020, 10(8), 297; https://doi.org/10.3390/geosciences10080297 - 03 Aug 2020
Viewed by 1012
Abstract
Identification of recharge areas in arid basins is challenging due to spatial and temporal variability and complexity of the hydrogeology. This study re-evaluates recharge mechanism in a desert basin where isotopic and geologic data indicated that published conceptual models of recharge are not [...] Read more.
Identification of recharge areas in arid basins is challenging due to spatial and temporal variability and complexity of the hydrogeology. This study re-evaluates recharge mechanism in a desert basin where isotopic and geologic data indicated that published conceptual models of recharge are not accurate. A new model of recharge is formulated that is consistent with the unique geologic framework in the basin. In the area of study, the Rio Grande flows across a broad alluvial floodplain, the “El Paso-Juarez Valley”, where the river has incised the surface of the Hueco Bolson. The modern Rio Grande floodplain overlies the older basin fill, or “Hueco Bolson deposits”, in the valley portion of the area. The lateral contact between the older bolson deposits and the recent alluvial floodplain deposits defines the “slope front”. The valley wall along the slope front is penetrated by many arroyos that incise the Hueco Bolson deposits and modern floodplain surface. The presence of a large lens of freshwater at the boundary between the older bolson fill and recent Rio Grande alluvium seemed to suggest to previous researchers that dilute water developed due to runoff drawn in by San Felipe Arroyo, a prominent arroyo at the slope front between the older Hueco Bolson deposits and the recent Rio Grande alluvium. Our follow-up verification work illustrates that this is demonstrably not the case. The testing of groundwater samples for stable water isotopes and radioisotopes showed that the deeper and more dilute waters near San Felipe Arroyo are actually pre-dam waters recharged from the shifting Rio Grande channel. Full article
(This article belongs to the Special Issue Groundwater in arid and semiarid areas)
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Article
Assessment of Depressional Wetland Degradation, Spatial Distribution, and Geological Aspects in Southern Brazil
Geosciences 2020, 10(8), 296; https://doi.org/10.3390/geosciences10080296 - 03 Aug 2020
Viewed by 1146
Abstract
This paper presents a procedure to study depressional wetlands in southern Brazil and focuses on the mechanisms controlling water dynamics and environmental degradation due to anthropogenic interference. The study is based on an inventory of wetlands, a digital elevation model, the geological and [...] Read more.
This paper presents a procedure to study depressional wetlands in southern Brazil and focuses on the mechanisms controlling water dynamics and environmental degradation due to anthropogenic interference. The study is based on an inventory of wetlands, a digital elevation model, the geological and geotechnical characteristics of geological materials, a multitemporal analysis of satellite images, the distribution of land use types, and onsite monitoring of water level and rainfall data. One hundred and twelve depressional wetlands were identified with a total area of 902 ha and a catchment area of 5456.8 ha. These wetlands were grouped into two classes with different hydrological control mechanisms. From the water level monitoring, the wetlands were found to present different hydrological conditions. Before rainy periods, the wetlands were almost dry or had little water; after rainy periods, over half of the wetlands were still dry or had groundwater levels below the surface, and the water levels of the other wetlands increased. The multitemporal analysis showed a reduction in the wetland water surface area from 270 ha in 1991 to 60 ha in 2019, which confirms the monitoring result that the amount of stored water is decreasing because of anthropogenic activities. Anthropogenic activities affect wetland water dynamics because of changes in the landscape and soil characteristics of the catchment area, and drainage of wetland areas by ditches for agricultural water supply; more than 50% of wetlands showed a high degree of change (environmental degradation), with conditions that make restoration or remediation very difficult. Full article
(This article belongs to the Section Hydrogeology)
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Article
Linking Siberian Traps LIP Emplacement and End-Permian Mass Extinction: Evidence from Magnetic Stratigraphy of the Maymecha-Kotuy Volcanic Section
Geosciences 2020, 10(8), 295; https://doi.org/10.3390/geosciences10080295 - 02 Aug 2020
Cited by 2 | Viewed by 1154
Abstract
The Siberian Traps Large Igneous Provinces (LIP) emplacement is considered as one of possible triggers for the end-Permian global biotic crisis. However, relative timing of the onset of extinction and the main phase of the magmatic activity are not yet accurately constrained. We [...] Read more.
The Siberian Traps Large Igneous Provinces (LIP) emplacement is considered as one of possible triggers for the end-Permian global biotic crisis. However, relative timing of the onset of extinction and the main phase of the magmatic activity are not yet accurately constrained. We present the detailed paleomagnetic data for the thickest composite section of the Siberian Traps volcanics, located in the Maymecha-Kotuy region. The major part of the Maymecha-Kotuy section erupted in the beginning of Early Triassic period and postdate came the onset of the biotic crisis. However, the initial pulse of volcanic activity in this region took place at the end of the Permian period, and likely preceded the extinction event, being nearly coeval to the lowest part of tuff-lava sequence of Norilsk. The suggested correlation scheme of volcanic sections from different regions of the Siberian platform shows that explosive and extrusive events foregoing the onset of extinction can be identified in almost all regions of the Siberian Traps LIP. Finally, we estimate the total duration of magmatic activity in the Maymecha-Kotuy region as ~2 Myr and assume that this lasted after the termination of eruptions in other parts of the Siberian platform. Full article
(This article belongs to the Special Issue Paleozoic Extinctions)
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