Pub Date : 2023-09-14DOI: 10.3390/geosciences13090280
Fabrizio Antonioli, Stefano Furlani, Giorgio Spada, Daniele Melini, Zomenia Zomeni
The Lambousa fishtank, an archaeological structure entirely carved in bedrock, can be easily recognized and measured in the plan on Google Earth (GE). We surveyed in situ this excellent archaeological marker in 2016 through direct measurements using traditional field instruments, such as metric tapes and invar rods, and terrestrial photogrammetry using Structure from Motion (SfM) methods. The bedrock on which the fishtank is founded is an Upper Pleistocene calcarenite also containing Persistrombus latus. The age of the studied fishtank has not been previously published, but on the basis of the construction technique and the interpretation provided by Archaelogist and references therein, we believe that it was built in the period between 2.1 and 1.8 ka BP, like similar fishtanks in the Mediterranean area. Architectural structures consist of evident foot walks (Crepido), a stone base, and a tunnel that allows for seawater exchange during high tides. The tunnel is at the same altitude as the Crepido, which lies around the fishtank. These architectural components allow us to evaluate the palaeo-sea level with significant precision during the time when the fishtank was active. MIS 5.5 coastal deposits that outcrop in the study area are located at a maximum altitude of a few meters, while the inner margin of the MIS 5.5 terrace allows us to hypothesize “quasi-tectonic stability”. We have also obtained several predictions of the contribution from Glacial Isostatic Adjustment (GIA) to relative sea level at Lambousa for the past 3.5 kyr, according to models ICE-6G (VM5a), ICE-7G (VM7), and one of the GIA models by the Australian National University ANU) Research group.
兰博萨鱼缸，一个完全雕刻在基岩上的考古结构，可以很容易地在谷歌地球(GE)的平面图中识别和测量。我们调查这个优秀的考古标记原位2016年通过直接使用传统测量仪器领域,如规磁带和不胀钢棒,和地面摄影测量使用结构与运动(SfM)方法。建立在鱼缸上的基岩为上更新世钙屑岩，也含有持续性龙岩。所研究的鱼缸的年龄以前没有发表过，但根据建造技术和考古学家提供的解释以及其中的参考文献，我们认为它建于2.1至1.8 ka BP之间，与地中海地区的类似鱼缸相似。建筑结构包括明显的步行道(Crepido)，石头基座和一个隧道，可以在涨潮时交换海水。隧道与克雷皮多位于同一高度，克雷皮多位于鱼缸周围。这些建筑构件使我们能够非常精确地评估鱼缸活动期间的古海平面。研究区出露的5.5级滨海矿床最大海拔高度仅为几米，而5.5级台地的内缘使我们可以假设“准构造稳定性”。我们还根据ICE-6G (VM5a)、ICE-7G (VM7)模型和澳大利亚国立大学(ANU)研究小组的一个GIA模型，获得了过去3.5 kyr兰博萨冰川均衡调整(GIA)对相对海平面的贡献的几个预测。
{"title":"The Lambousa (Cyprus) Fishtank in a Quasi-Stable Coastal Area of the Eastern Mediterranean, a Notable Marker for Testing GIA Models","authors":"Fabrizio Antonioli, Stefano Furlani, Giorgio Spada, Daniele Melini, Zomenia Zomeni","doi":"10.3390/geosciences13090280","DOIUrl":"https://doi.org/10.3390/geosciences13090280","url":null,"abstract":"The Lambousa fishtank, an archaeological structure entirely carved in bedrock, can be easily recognized and measured in the plan on Google Earth (GE). We surveyed in situ this excellent archaeological marker in 2016 through direct measurements using traditional field instruments, such as metric tapes and invar rods, and terrestrial photogrammetry using Structure from Motion (SfM) methods. The bedrock on which the fishtank is founded is an Upper Pleistocene calcarenite also containing Persistrombus latus. The age of the studied fishtank has not been previously published, but on the basis of the construction technique and the interpretation provided by Archaelogist and references therein, we believe that it was built in the period between 2.1 and 1.8 ka BP, like similar fishtanks in the Mediterranean area. Architectural structures consist of evident foot walks (Crepido), a stone base, and a tunnel that allows for seawater exchange during high tides. The tunnel is at the same altitude as the Crepido, which lies around the fishtank. These architectural components allow us to evaluate the palaeo-sea level with significant precision during the time when the fishtank was active. MIS 5.5 coastal deposits that outcrop in the study area are located at a maximum altitude of a few meters, while the inner margin of the MIS 5.5 terrace allows us to hypothesize “quasi-tectonic stability”. We have also obtained several predictions of the contribution from Glacial Isostatic Adjustment (GIA) to relative sea level at Lambousa for the past 3.5 kyr, according to models ICE-6G (VM5a), ICE-7G (VM7), and one of the GIA models by the Australian National University ANU) Research group.","PeriodicalId":38189,"journal":{"name":"Geosciences (Switzerland)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134914419","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Advances in research on environmental problems and public awareness of them have led to renewed concern about the need to establish mechanisms and figures to protect and manage sites so that geoecological processes remain outside the dynamics of anthropic occupation. This research has been approached from an inductive and qualitative perspective based on case studies to examine the articulation of the Spanish geoparks, their dynamics, and the experiences of private valorization in them. Geological heritage is seen as a lever for the promotion of the territory. In all cases, although the geological–geomorphological–paleontological–environmental resources must be significant, this designation aims to enhance the value of all assets, both natural and cultural, conceiving the geopark not as a figure of environmental protection but as a “figure to promote local development”. A total of 48 land stewardship initiatives were identified in 11 of the 15 Spanish geoparks. The most significant presence of initiatives was found in the geoparks of Catalonia, followed by the Lanzarote Geopark. No nature-based schools are located within geoparks, except for Wild Me in Central Catalonia. However, the presence of nature-based schools in biosphere reserves (BRs) seems to be more common. Framing alternative proposals, such as nature-based schools in these areas and using land stewardship in their operation, can become an opportunity to protect a region’s geological and cultural heritage and improve local communities’ quality of life through sustainable and responsible economic and tourism activities. Early-years education in the natural environment facilitates the acquisition of long-term pro-environmental skills, competencies, and behaviors that last into adulthood and act as multipliers for others.
{"title":"Conservation and Education in Spanish Geoparks: Exploratory Analysis of Land Stewardship Experiences and Valuation Proposal through Outdoor Education","authors":"Emilio Iranzo-García, Katia Hueso-Kortekaas, Ghaleb Fansa-Saleh","doi":"10.3390/geosciences13090276","DOIUrl":"https://doi.org/10.3390/geosciences13090276","url":null,"abstract":"Advances in research on environmental problems and public awareness of them have led to renewed concern about the need to establish mechanisms and figures to protect and manage sites so that geoecological processes remain outside the dynamics of anthropic occupation. This research has been approached from an inductive and qualitative perspective based on case studies to examine the articulation of the Spanish geoparks, their dynamics, and the experiences of private valorization in them. Geological heritage is seen as a lever for the promotion of the territory. In all cases, although the geological–geomorphological–paleontological–environmental resources must be significant, this designation aims to enhance the value of all assets, both natural and cultural, conceiving the geopark not as a figure of environmental protection but as a “figure to promote local development”. A total of 48 land stewardship initiatives were identified in 11 of the 15 Spanish geoparks. The most significant presence of initiatives was found in the geoparks of Catalonia, followed by the Lanzarote Geopark. No nature-based schools are located within geoparks, except for Wild Me in Central Catalonia. However, the presence of nature-based schools in biosphere reserves (BRs) seems to be more common. Framing alternative proposals, such as nature-based schools in these areas and using land stewardship in their operation, can become an opportunity to protect a region’s geological and cultural heritage and improve local communities’ quality of life through sustainable and responsible economic and tourism activities. Early-years education in the natural environment facilitates the acquisition of long-term pro-environmental skills, competencies, and behaviors that last into adulthood and act as multipliers for others.","PeriodicalId":38189,"journal":{"name":"Geosciences (Switzerland)","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135740720","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-13DOI: 10.3390/geosciences13090277
Anna Małka, Lesław Zabuski, Frieder Enzmann, Arkadiusz Krawiec
This work aims to analyse the mechanisms and factors contributing to shallow soil landslides in river valleys entrenched in lowlands on the example of the Central Radunia Valley. The combination of susceptibility analysis using geographic-information-system-based statistical models, field surveys, analysis of archival materials, and numerical modelling for the analysis of slope stability and hydrogeological processes allows for comprehensive landslide reconstruction, mass movement mechanism description, and an explanation of the role of triggering and causal factors. The results emphasise the need for cross-disciplinary studies of shallow soil landslides. The identification and prioritisation of the causal factors indicate that geomorphological conditions play a particularly important role. The current study shows that the greatest influence on landslide formation in the Central Radunia Valley is slope angle, as determined using a high-resolution digital elevation model. The slope angle factor is sufficient to produce a reliable susceptibility map (the areas under the curve of the success rate and prediction rate curves are 87.84% and 85.34%, respectively). However, numerical modelling of slope failure also clearly indicated that there was a significant influence of anthropogenic impacts on the landslide process. We determined that the main triggering factor causing the January 2019 Rutki landslide was related to the drilling of a borehole on 10 January 2019. The water used for drilling hydrated the soil and thus weakened the stability conditions.
{"title":"Mass-Movement Causes and Landslide Susceptibility in River Valleys of Lowland Areas: A Case Study in the Central Radunia Valley, Northern Poland","authors":"Anna Małka, Lesław Zabuski, Frieder Enzmann, Arkadiusz Krawiec","doi":"10.3390/geosciences13090277","DOIUrl":"https://doi.org/10.3390/geosciences13090277","url":null,"abstract":"This work aims to analyse the mechanisms and factors contributing to shallow soil landslides in river valleys entrenched in lowlands on the example of the Central Radunia Valley. The combination of susceptibility analysis using geographic-information-system-based statistical models, field surveys, analysis of archival materials, and numerical modelling for the analysis of slope stability and hydrogeological processes allows for comprehensive landslide reconstruction, mass movement mechanism description, and an explanation of the role of triggering and causal factors. The results emphasise the need for cross-disciplinary studies of shallow soil landslides. The identification and prioritisation of the causal factors indicate that geomorphological conditions play a particularly important role. The current study shows that the greatest influence on landslide formation in the Central Radunia Valley is slope angle, as determined using a high-resolution digital elevation model. The slope angle factor is sufficient to produce a reliable susceptibility map (the areas under the curve of the success rate and prediction rate curves are 87.84% and 85.34%, respectively). However, numerical modelling of slope failure also clearly indicated that there was a significant influence of anthropogenic impacts on the landslide process. We determined that the main triggering factor causing the January 2019 Rutki landslide was related to the drilling of a borehole on 10 January 2019. The water used for drilling hydrated the soil and thus weakened the stability conditions.","PeriodicalId":38189,"journal":{"name":"Geosciences (Switzerland)","volume":"38 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135783076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-12DOI: 10.3390/geosciences13090274
Michael Walther, Ulrich Kamp
There are different ideas about the classification and distribution of permafrost in Mongolia. Terms such as continuous, discontinuous, sporadic, and isolated permafrost are inconsistently applied; hence, maps of permafrost display different distribution patterns. Particularly, the southern border of the Siberian permafrost in Mongolia is still debated. Furthermore, comparing these maps is challenging when studying impacts of climate change on permafrost. While, without a doubt, Mongolia’s permafrost is in a stage of significant degradation and has receded from vast regions, telling this story is difficult when data are not easily comparable. Today, all permafrost is restricted to Mongolia’s mountains. To better describe permafrost that depends on orography and elevation, we propose to use the more appropriate term ‘mountain permafrost.’ Surprisingly, the term ‘periglacial’ is mostly absent in the literature on Mongolia’s permafrost. We here aim to clarify definitions of terms and hope that future studies will pay attention to both periglacial environments and mountain permafrost.
{"title":"Mountain Permafrost: A Reflection on the Periglacial Environment in Mongolia","authors":"Michael Walther, Ulrich Kamp","doi":"10.3390/geosciences13090274","DOIUrl":"https://doi.org/10.3390/geosciences13090274","url":null,"abstract":"There are different ideas about the classification and distribution of permafrost in Mongolia. Terms such as continuous, discontinuous, sporadic, and isolated permafrost are inconsistently applied; hence, maps of permafrost display different distribution patterns. Particularly, the southern border of the Siberian permafrost in Mongolia is still debated. Furthermore, comparing these maps is challenging when studying impacts of climate change on permafrost. While, without a doubt, Mongolia’s permafrost is in a stage of significant degradation and has receded from vast regions, telling this story is difficult when data are not easily comparable. Today, all permafrost is restricted to Mongolia’s mountains. To better describe permafrost that depends on orography and elevation, we propose to use the more appropriate term ‘mountain permafrost.’ Surprisingly, the term ‘periglacial’ is mostly absent in the literature on Mongolia’s permafrost. We here aim to clarify definitions of terms and hope that future studies will pay attention to both periglacial environments and mountain permafrost.","PeriodicalId":38189,"journal":{"name":"Geosciences (Switzerland)","volume":"33 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135825990","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-12DOI: 10.3390/geosciences13090275
Maryam Sheibi, Nima Rahimi, Pierre Rochette, François Demory, Hassan Mirnejad
Magnetic fabric, paleomagnetic, and petrophysical studies were conducted on rocks in the Tafresh area of the central Urumieh-Dokhtar magmatic arc in Iran. The samples included Late Triassic dark gray sandstone, a mafic dyke, diorites, and a felsic dyke in the Zaghar region. Hydrothermal alteration in the Spid intrusion was investigated to understand the effects of alteration on magnetic fabric patterns. The AMS measurements support the theory that the Nayband Formation was constructed under a crustal extension regime. Magnetic susceptibility anisotropy in a microdioritic dyke indicates compression from the NNE-SSW, likely due to tectonic activity. AMS results from diorites in Zaghar suggest intrusions were emplaced in extensional spaces between the Tafresh and Chaghar thrust faults. The Spid intrusion’s magnetite is the primary carrier of magnetic susceptibility, but hydrothermal alteration has partly converted it into hematite, resulting in lower susceptibility and higher porosity in altered diorites. This process leads to a bimodal distribution of magnetic lineation trends. The Spid and Zaghar massifs underwent a northward tilt of about 30 degrees around an east-west axis following the Early Miocene. Post-Eocene rotations in the area are typically within ±20 degrees. This study demonstrates how magnetic properties can provide new insights into the evolution of tectono-magmatic processes and structural controls within a magmatic arc.
{"title":"Magnetic Fabric and Paleomagnetic Analyses of the Zaghar and Tafresh Areas, Central Urumieh-Dokhtar Magmatic Arc, Iran","authors":"Maryam Sheibi, Nima Rahimi, Pierre Rochette, François Demory, Hassan Mirnejad","doi":"10.3390/geosciences13090275","DOIUrl":"https://doi.org/10.3390/geosciences13090275","url":null,"abstract":"Magnetic fabric, paleomagnetic, and petrophysical studies were conducted on rocks in the Tafresh area of the central Urumieh-Dokhtar magmatic arc in Iran. The samples included Late Triassic dark gray sandstone, a mafic dyke, diorites, and a felsic dyke in the Zaghar region. Hydrothermal alteration in the Spid intrusion was investigated to understand the effects of alteration on magnetic fabric patterns. The AMS measurements support the theory that the Nayband Formation was constructed under a crustal extension regime. Magnetic susceptibility anisotropy in a microdioritic dyke indicates compression from the NNE-SSW, likely due to tectonic activity. AMS results from diorites in Zaghar suggest intrusions were emplaced in extensional spaces between the Tafresh and Chaghar thrust faults. The Spid intrusion’s magnetite is the primary carrier of magnetic susceptibility, but hydrothermal alteration has partly converted it into hematite, resulting in lower susceptibility and higher porosity in altered diorites. This process leads to a bimodal distribution of magnetic lineation trends. The Spid and Zaghar massifs underwent a northward tilt of about 30 degrees around an east-west axis following the Early Miocene. Post-Eocene rotations in the area are typically within ±20 degrees. This study demonstrates how magnetic properties can provide new insights into the evolution of tectono-magmatic processes and structural controls within a magmatic arc.","PeriodicalId":38189,"journal":{"name":"Geosciences (Switzerland)","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135826931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-10DOI: 10.3390/geosciences13090273
Kate Andrzejewski, Greg Ludvigson, Marina Suarez, Paul McCarthy, Peter Flaig
We report estimated stable isotope compositions of Artic paleoprecipitation using phyllosilicates sampled from three paleosols and two bentonites in the Prince Creek Formation (Maastrichtian) in northern Alaska. Previous studies reported a deuterium excess in estimates of Arctic paleoprecipitation from the Late Cretaceous by combining hydrogen and oxygen proxy sources, including pedogenic minerals, dinosaurian tooth enamel phosphates, pedogenic siderites, and n-alkane biomarkers. The new dataset produced in this study removes uncertainty on possible explanations (photosynthetic and transpiration) of the deuterium excess by producing stable hydrogen and oxygen isotopic signatures from the same source material. The δD of the phyllosilicates range from −171‰ to −72‰ VSMOW and δ18O ranges from 5.0 to 11.8‰ VSMOW. By assuming a MAT of 6.3 °C and calculating uniquely derived fractionation equations for each phyllosilicate, we report estimated isotopic composition of Late Cretaceous paleoprecipitation with an average δD value of −133‰ VSMOW, corresponding to an average δ18O value of −20.3‰ VSMOW. The estimates of Late Cretaceous paleoprecipitation do not intersect the Global Meteoric Water Line and reveal a reported deuterium excess ranging from 7 to 46 per mil. These results confirm the presence of a deuterium excess in Late Cretaceous Arctic paleoprecipitation and provide new insight to assessing possible explanations for this phenomenon.
{"title":"Exploring the Deuterium Excess of Cretaceous Arctic Paleoprecipitation Using Stable Isotope Composition of Clay Minerals from the Prince Creek Formation (Maastrichtian) in Northern Alaska","authors":"Kate Andrzejewski, Greg Ludvigson, Marina Suarez, Paul McCarthy, Peter Flaig","doi":"10.3390/geosciences13090273","DOIUrl":"https://doi.org/10.3390/geosciences13090273","url":null,"abstract":"We report estimated stable isotope compositions of Artic paleoprecipitation using phyllosilicates sampled from three paleosols and two bentonites in the Prince Creek Formation (Maastrichtian) in northern Alaska. Previous studies reported a deuterium excess in estimates of Arctic paleoprecipitation from the Late Cretaceous by combining hydrogen and oxygen proxy sources, including pedogenic minerals, dinosaurian tooth enamel phosphates, pedogenic siderites, and n-alkane biomarkers. The new dataset produced in this study removes uncertainty on possible explanations (photosynthetic and transpiration) of the deuterium excess by producing stable hydrogen and oxygen isotopic signatures from the same source material. The δD of the phyllosilicates range from −171‰ to −72‰ VSMOW and δ18O ranges from 5.0 to 11.8‰ VSMOW. By assuming a MAT of 6.3 °C and calculating uniquely derived fractionation equations for each phyllosilicate, we report estimated isotopic composition of Late Cretaceous paleoprecipitation with an average δD value of −133‰ VSMOW, corresponding to an average δ18O value of −20.3‰ VSMOW. The estimates of Late Cretaceous paleoprecipitation do not intersect the Global Meteoric Water Line and reveal a reported deuterium excess ranging from 7 to 46 per mil. These results confirm the presence of a deuterium excess in Late Cretaceous Arctic paleoprecipitation and provide new insight to assessing possible explanations for this phenomenon.","PeriodicalId":38189,"journal":{"name":"Geosciences (Switzerland)","volume":"87 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136072513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-08DOI: 10.3390/geosciences13090272
George Xiroudakis, George Saratsis, Ilias Lazos
This paper uses the displacement discontinuity method, one of the boundary element methods, to solve two major engineering problems. The first one addresses the safe design of underground excavations in fractured rock masses. The implemented method was used to control the slip of discontinuities passing through a circular opening at 45°. Special contact elements were used to simulate a possible slip on the cracks. At the same time, stress intensity factors (SIFs) were calculated using the gradient elasticity theory (special tip elements where numerical integrations are needed were excluded). The crack propagation due to shear slip occurrence was defined using the criterion of maximum tangential stress at an angle of 71° from the initial crack direction. The second one involved in the crack’s propagation was solved by applying pressure to the circular opening, while a part of it was transferred to the cracks, approximating the mechanism of hydraulic fracture. Finally, the implementation of higher elasticity elements in the cracks provided an accurate estimation of SIFs, showing an error of about 4%, as confirmed by comparisons with existing type I loading solutions.
{"title":"Implementation of the Displacement Discontinuity Method in Geotechnical Case Studies","authors":"George Xiroudakis, George Saratsis, Ilias Lazos","doi":"10.3390/geosciences13090272","DOIUrl":"https://doi.org/10.3390/geosciences13090272","url":null,"abstract":"This paper uses the displacement discontinuity method, one of the boundary element methods, to solve two major engineering problems. The first one addresses the safe design of underground excavations in fractured rock masses. The implemented method was used to control the slip of discontinuities passing through a circular opening at 45°. Special contact elements were used to simulate a possible slip on the cracks. At the same time, stress intensity factors (SIFs) were calculated using the gradient elasticity theory (special tip elements where numerical integrations are needed were excluded). The crack propagation due to shear slip occurrence was defined using the criterion of maximum tangential stress at an angle of 71° from the initial crack direction. The second one involved in the crack’s propagation was solved by applying pressure to the circular opening, while a part of it was transferred to the cracks, approximating the mechanism of hydraulic fracture. Finally, the implementation of higher elasticity elements in the cracks provided an accurate estimation of SIFs, showing an error of about 4%, as confirmed by comparisons with existing type I loading solutions.","PeriodicalId":38189,"journal":{"name":"Geosciences (Switzerland)","volume":"54 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136363103","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-07DOI: 10.3390/geosciences13090271
A. Karakonstantis, F. Vallianatos
This study delves into the southern Aegean regionwhere the subduction of the oceanic Mediterranean lithosphere under the Aegean continental one takes place. This region is considered one of the most active ones in the eastern Mediterranean Sea due to intense tectonic movements in the Late Quaternary. More than 1200 manually revised events from 2018 to 2023 have been used in order to obtain the 3D structure of body-wave velocity and VP/VS ratioto 80 km depth through earthquaketomography. A series of resolution tests have been performed and demonstrated fair resolution of the derived velocity structures in the area of interest. The derived anomalies of body-waves (dVP, dVS) and VP/VS ratio provided important information about the southern Aegean regional tectonics and secondarily active faults of smaller scale (>20 km). The region is marked by significant low-velocity anomalies in the crust and uppermost mantle, beneath the active arc volcanoes. The seismicity related to the Hellenic Subduction Zone (HSZ) is connected to a low-angle positive anomaly of VP and VS, correlated withthe observed intermediate-depth seismicity (H ≥ 40 km) in this part of the study area. This result could be related to the diving HSZ slab.
{"title":"3D Body-Wave Velocity Structure of the Southern Aegean, Greece","authors":"A. Karakonstantis, F. Vallianatos","doi":"10.3390/geosciences13090271","DOIUrl":"https://doi.org/10.3390/geosciences13090271","url":null,"abstract":"This study delves into the southern Aegean regionwhere the subduction of the oceanic Mediterranean lithosphere under the Aegean continental one takes place. This region is considered one of the most active ones in the eastern Mediterranean Sea due to intense tectonic movements in the Late Quaternary. More than 1200 manually revised events from 2018 to 2023 have been used in order to obtain the 3D structure of body-wave velocity and VP/VS ratioto 80 km depth through earthquaketomography. A series of resolution tests have been performed and demonstrated fair resolution of the derived velocity structures in the area of interest. The derived anomalies of body-waves (dVP, dVS) and VP/VS ratio provided important information about the southern Aegean regional tectonics and secondarily active faults of smaller scale (>20 km). The region is marked by significant low-velocity anomalies in the crust and uppermost mantle, beneath the active arc volcanoes. The seismicity related to the Hellenic Subduction Zone (HSZ) is connected to a low-angle positive anomaly of VP and VS, correlated withthe observed intermediate-depth seismicity (H ≥ 40 km) in this part of the study area. This result could be related to the diving HSZ slab.","PeriodicalId":38189,"journal":{"name":"Geosciences (Switzerland)","volume":"36 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2023-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86726578","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-07DOI: 10.3390/geosciences13090270
E. Volpe, S. L. Gariano, L. Ciabatta, Yaser Peiro, E. Cattoni
Cultural heritage is one of the most exceptional resources characterizing the Italian territory. Archaeological heritage, i.e., the archaeological sites with different types of archaeological artifacts, strongly contributes to enriching the national and international cultural heritage. Nevertheless, it is constantly exposed to external factors, such as natural deterioration, anthropic impact, and climate-related hazards, which may compromise its conservation. In Italy, many archaeological areas are affected by significant soil settlements that involve a large part of monuments. This paper focuses on the landslide hazard assessment of the archaeological site of Pietrabbondante (Molise region, Italy). The impact of the expected rainfall regimes, according to the EURO-CORDEX projections, on slope stability conditions were evaluated through the application of a physically based model that couples a hydraulic and a mechanical model to evaluate slope stability evolution due to pore pressure changes. Given the unavoidable lack of knowledge of the geotechnical soil properties in an archaeological heritage area, the proposed method considered the random uncertainty of soil parameters by means of a probabilistic approach in order to assess the stability conditions in terms of probability of occurrence of a landslide. The results of this study provide a reference for the safety assessment and preventive conservation of archaeological areas characterized by high cultural value.
{"title":"Expected Changes in Rainfall-Induced Landslide Activity in an Italian Archaeological Area","authors":"E. Volpe, S. L. Gariano, L. Ciabatta, Yaser Peiro, E. Cattoni","doi":"10.3390/geosciences13090270","DOIUrl":"https://doi.org/10.3390/geosciences13090270","url":null,"abstract":"Cultural heritage is one of the most exceptional resources characterizing the Italian territory. Archaeological heritage, i.e., the archaeological sites with different types of archaeological artifacts, strongly contributes to enriching the national and international cultural heritage. Nevertheless, it is constantly exposed to external factors, such as natural deterioration, anthropic impact, and climate-related hazards, which may compromise its conservation. In Italy, many archaeological areas are affected by significant soil settlements that involve a large part of monuments. This paper focuses on the landslide hazard assessment of the archaeological site of Pietrabbondante (Molise region, Italy). The impact of the expected rainfall regimes, according to the EURO-CORDEX projections, on slope stability conditions were evaluated through the application of a physically based model that couples a hydraulic and a mechanical model to evaluate slope stability evolution due to pore pressure changes. Given the unavoidable lack of knowledge of the geotechnical soil properties in an archaeological heritage area, the proposed method considered the random uncertainty of soil parameters by means of a probabilistic approach in order to assess the stability conditions in terms of probability of occurrence of a landslide. The results of this study provide a reference for the safety assessment and preventive conservation of archaeological areas characterized by high cultural value.","PeriodicalId":38189,"journal":{"name":"Geosciences (Switzerland)","volume":"133 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2023-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79667851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-06DOI: 10.3390/geosciences13090269
A. Dura, P. Nomikou, T. Mertzimekis, M. Hannington, Sven Petersen, Serafim Poulos
The presence of active hydrothermal vent fields near residential areas and their possible link to volcanic activity poses a potential hazard to the environment, society, and the economy. By capitalizing on Autonomous Underwater Vehicle sampling methodologies and applying the Generalized Moments Method model for geological and physical processes in these environments, we shed light on the underlying dynamics shaping the physicochemical characteristics of the vents. In this study, we focus on the Northern Caldera of Santorini and, more specifically, on the recorded CTD data (Conductivity, Temperature, Depth). The data sets were collected in 2017 in Santorini using an Autonomous Underwater Vehicle during the GEOMAR POS510 mission. Our research shows that the active vent field within the caldera probably follows a multifractal behavior and exhibits a weak memory effect. Depth Profiles and Time Series show similar behavior among conductivity and temperature. The variance and moments of both parameters underline the existence of two different mechanisms governing the behavior of the vent field. Finally, the structure function shows that changes in the time series are described by a Cauchy–Lorentz distribution.
{"title":"Identifying Probable Submarine Hydrothermal Spots in North Santorini Caldera Using the Generalized Moments Method","authors":"A. Dura, P. Nomikou, T. Mertzimekis, M. Hannington, Sven Petersen, Serafim Poulos","doi":"10.3390/geosciences13090269","DOIUrl":"https://doi.org/10.3390/geosciences13090269","url":null,"abstract":"The presence of active hydrothermal vent fields near residential areas and their possible link to volcanic activity poses a potential hazard to the environment, society, and the economy. By capitalizing on Autonomous Underwater Vehicle sampling methodologies and applying the Generalized Moments Method model for geological and physical processes in these environments, we shed light on the underlying dynamics shaping the physicochemical characteristics of the vents. In this study, we focus on the Northern Caldera of Santorini and, more specifically, on the recorded CTD data (Conductivity, Temperature, Depth). The data sets were collected in 2017 in Santorini using an Autonomous Underwater Vehicle during the GEOMAR POS510 mission. Our research shows that the active vent field within the caldera probably follows a multifractal behavior and exhibits a weak memory effect. Depth Profiles and Time Series show similar behavior among conductivity and temperature. The variance and moments of both parameters underline the existence of two different mechanisms governing the behavior of the vent field. Finally, the structure function shows that changes in the time series are described by a Cauchy–Lorentz distribution.","PeriodicalId":38189,"journal":{"name":"Geosciences (Switzerland)","volume":"12 1","pages":""},"PeriodicalIF":2.7,"publicationDate":"2023-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81005619","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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