Landslides vs Archaeology

Landslides are one of the few types of natural hazards that have affected Sweden regularly in the recent past. We can expect that this geological phenomenon will only increase in frequency in the near future given the ongoing processes of anthropogenic climate change, and this likelihood motivates some historical retrospection. This paper explores how landslides have impacted archaeological sites in Västra Götaland, the country’s most landslide-prone region, from the mid-twentieth century onwards, and how, in turn, archaeologists have had to respond to these disasters. The 1957 Göta, 1973 Fröland, 1977 Tuve and 2006 Småröd landslides are highlighted in particular, as is the landslide-impacted site Hjälpesten. Connections are made to other different but related archaeologies of hazard and disaster, providing insights into the impact that climate change has had and will have on the discipline. While the paper showcases a set of local case studies, it is further argued that its findings have relevance for other areas as well, calling for the attention of the cultural heritage sector.

Semi-automated assessment of geological phenomena of Active Deformation Areas (ADA) detected by radar interferometry in Alt Urgell and Cerdanya, Catalonia (Spain)

<p>Geological hazards related to ground movements are difficult to assess at a regional scale due the lack of detailed information on the occurrence of the phenomena and the large number of potential vulnerable elements in the territory. Therefore, progress in analyzes at the regional scale can be a very useful tool for risk management.</p><p>This work, developed in the Alt Urgell and La Cerdanya counties (Catalunya, NE Spain) has served as the basis for the geological risk identification associated with ground movements. The methodology is based on the use of the Active Deformation Areas (ADA) detected by medium resolution radar satellite interferometry (Sentinel-1A and Sentinel-1B). The goal is to obtain a quick and semi-automatically classification of the ADAs according to the probable geological phenomena origin (landslides, rockfalls and subsidence).</p><p>This ADA classification is based on current data (DTM and geology) and easy to implement with GIS, takes in account: (i), landslide inventories, to allow the direct validation of the geological phenomenon; (ii) geology -information of the geological units type-; (iii) slope terrain -morphology-, determines the classification of the movement cause, depending on the slope, they are more or less prone to the generation of geological phenomena (e.g. slopes <35º: landslides); and (iv) land uses, determines the potential impact on vulnerable areas (e.g. high, in urbanized areas; low, in natural environments). This methodology provides an ADA first geological susceptibility categorization that allows optimizing and prioritizing efforts in detailed geological and geomorphological characterization works.</p><p>The clustering of scattering points gave a result of 361 ADA (over an area of around 2,000 km<sup>2</sup>), 145 was classified as potentially generated by a geological phenomenon (126 susceptible to landslides, 7 as rockfalls, 7 as subsidence and 5 as landslides or rockfalls) and 215 were classified as other causes.</p><p>Ideally, validation is based on contrasting the ADA with actual inventory data. However, the lack of complete and exhaustive inventories require validation based on classic methods such as photointerpretation and field work. All areas were checked by means of geomorphological analysis to ensure their susceptibility: 143 has identified as caused by geological phenomena, 153 has related with geological depositional process (rocky ground) and 65 has discarded.</p><p>This work has been supported by the European Commission under the Interreg V-A-POCTEFA programme (grant no. Mompa – EFA295/19).</p>

Exogenous relief-forming processes and phenomena on the territory of the Chechen Republic

Landslide, also known as landslide, is a geological phenomenon that includes a wide range of ground movements such as rockfalls, deep slope collapse and shallow mudflows. Landslides can occur at sea, on the coast and on land. While gravity is the main driving force behind a landslide, there are other factors that affect the initial stability of the slope. Typically, preconditions create certain subsurface conditions that make the site / slope prone to collapse, while the actual landslide often requires a trigger before being triggered. Landslide studies help identify weak areas, classify hillsides into different categories, and minimize the impact of landslides.

Detecting Coastal Atmosphere Weathering Process on Andesite Rock Using Magnetic Susceptibility and Fe3O4/Fe2O3 Ratio

Weathering is a geological phenomenon that is often an important considered because of its destructive properties, mainly in subsurface. Many parameters are used to measure the presence of weathering indications. This study focuses on testing of magnetic susceptibility (c), compound oxide content and Fe3O4/Fe2O3 ratio that have been selected as an indicators of weathering process. This study explains in detail the quantitative analysis of weathering based on these parameters in basaltic andesite rocks found in coastal atmospheric areas. The results obtained for weathered rocks, magnetic susceptibility, compound oxide content such as CaO and the Fe3O4/Fe2O3 ratio has decreased significantly. In the coastal atmosphere, the weathering of basaltic andesite rocks also marked by the distribution of magnetic minerals which tend to be in the domain of pseudo single domain (PSD) or single domain (SD). Thus it can be concluded that both of low frequency magnetic susceptibility (clf), CaO and Fe2O3 content and also the Fe3O4/Fe2O3 ratio can be used as weathering level indicators.

Factors that condition physical vulnerability to ground fracturing in Mexico City

In spite of subsidence being a well-studied geological phenomenon in Mexico City, its effects and risks for urban infrastructure and inhabitants have been neglected. Damage in the short, medium and long term implies maintenance and important mitigation costs. There are not systematic studies that address methodologies for the estimation of physical vulnerability of the geological media to fracture. In this work, factors conditioning the deformation and susceptibility to fracturing are analyzed using a deterministic approach. The identified physical variables were mapped, measured and integrated into a database that allowed for an adequate correlation of the parameters that condition fractures spatial distribution. A methodology for estimating a vulnerability index to fracturing (VIF) useful for decision making is proposed in this work.

Sagging-collapse sinkholes: simulation modelling

In the paper a kind of sinkholes is considered, which is typical for areas where soluble rocks are covered by clay’s layer overlapped by saturated sands. The presence in soluble rocks of non-filled cavity contacting with covering clays is necessary to the sinkhole formation, however it can be provoked not only by cavity’s enlarging but else by changes of groundwater levels. The mechanism of this complex process has been researched by its in-laboratory simulation modelling, and its results can possibility to the author to name this phenomenon as “sagging-collapse sinkholes”, because it includes sagging and collapse of clays accompanied by downward moving of sands and sometimes by their liquefaction. Modelling technology is given in the paper in detail and the conception of investigated process is offered. Except experimental study of sagging-sinkhole formation the purposes of the work was quantitative forecasting of this geological phenomenon. Forecasts have been developed that allow calculating the diameter of the expected sinkhole, particularly. An assessment of their reliability is given.

NEW DATA ON SEASONAL MINERALS OF MUD VOLCANOES IN AZERBAIJAN

The article discusses the morphology and material composition of seasonal minerals of mud volcanoes in Azerbaijan Mud volcanism is a complex and rather unexplored geological phenomenon. Mud volcanoes are known in Turkmenistan, Dagestan, Georgia, Sakhalin, Taman Peninsula, Crimea, Azerbaijan and many regions of the World. In the geological literature, this phenomenon has been widely reflected. The bibliography of scientific works on mud volcanism has hundreds of titles. One of the classic areas of mud volcano development is Azerbaijan. In the process of geological research in recent decades, a huge geological material has been accumulated on the mud volcanism of Azerbaijan. The described types of mud volcanoes eruptions and the material composition of the mound breccia, it was possible to discover new interesting facts of unusual mineralogical finds. Of particular interest are authigenic minerals formed directly from the water phase of mud volcanoes and are seasonal. Their formation indicates that mineral formation processes are active in these natural sites. The occurrence of seasonal minerals is controlled by several factors, including the climatic conditions of the region. Main part of such minerals crystallizes only in dry and warm weather, which makes their systematic research much more difficult. The sodium hydroxide described in the article, which is very unstable under natural conditions, is a confirmation of this. However, even for a short interval of the existence of seasonal minerals, studying the features of their composition, one can obtain important information for genetic constructions. In addition to exogenous minerals of the weathering zone, the article also describes molybdenite associated with hydrothermal processes. The study of the mineral component of both endogenous and exogenous processes makes it possible to assess their evolution, the direction of the geological development of mud volcanoes in the region.

Geoheritage in Deltaic Environments: Classification Notes, Case Example, and Geopark Implication

River deltas boast ecosystem richness, but their efficient conservation and management require consideration of the full spectrum of natural phenomena, including those which are geological. Few specialists have explored the issue of deltaic geological heritage (geoheritage), and the relevant knowledge remains scarce and non-systematised. This paper proposes the first classification of this geoheritage. Five categories are distinguished: entire-delta geological phenomenon, delta-associated “purely” geological features, delta-associated features resulting from geology–ecosystem interactions, geological features occasional to deltas, and geoarchaeological localities in deltas. Chosen as a case example, the Don River delta in the southwestern part of Russia possesses geoheritage of these categories, except for the latter. The relevant unique geological features differ by their types and ranks. Of particular interest is the phenomenon of a self-cleaning environment which prevents mercury concentration in the soil despite pollution from natural and anthropogenic sources. The complexity of the deltaic geoheritage, its co-existence with the rich biodiversity, and the aesthetical issues make geopark creation in river deltas a sensible venture. Relevant proposals have been made for Malaysia and the Netherlands–Belgium border, and the Don River delta in Russia also presents an appropriate location for geopark creation.