Search

Landslide research chiefly relies on digital inventories for a multitude of spatial, temporal, and/or process analyses. In respect thereof, many landslide inventories are populated with information from textual documents (e.g., news articles, technical reports) due to effectiveness. However, information detail can vary greatly in these documents and the question arises whether such textual information is suitable for landslide inventories. The present work proposes to define the usefulness of textual source types as a probability to find landslide information, weighted with adaptable parameter requirements. To illustrate the method with practical results, a German landslide dataset has been examined. It was found that three combined source types (administrative documents, expert opinions, and news articles) give an 89 % chance to detect useful information on three defined parameters (location, date, and process type). In conclusion, the definition of usefulness as a probability makes it an intuitive, quantitative measure that is suitable for a wide range of applicants. Furthermore, a priori knowledge of usefulness allows for focusing on a few source types with the most promising outcome and thus increases the effectiveness of textual data acquisition and digitalisation for landslide inventories. [ABSTRACT FROM AUTHOR]

Landslide research relies on landslide inventories for a multitude of spatial, temporal, or process analyses. Generally, it takes high effort to populate a landslide inventory with relevant data. In this context, the present work investigated an effective way to handle vast amounts of automatically acquired digital data for landslide inventories by the use of machine learning algorithms and information filtering. Between July 2017 and February 2019, a keyword alert system provided 4381 documents that were automatically processed to detect landslide events in Germany. Of all those documents, 91% were automatically recognized as irrelevant or duplicates; thereby, the data volume was significantly reduced to contain only actual landslide documents. Moreover, it was shown that inclusion of the document's images into the automated process chain for information filtering is recommended, since otherwise unobtainable important information was found in them. Compared with manual methods, the automated process chain eliminated personal idiosyncrasies and human error and replaced it with a quantifiable machine error. The applied individual algorithms for natural language processing, information retrieval, and classification have been tried and tested in their respective fields. Furthermore, the proposed method is not restricted to a specific language or region. All languages on which these algorithms are applicable can be used with the proposed method and the training of the process chain can take any geographical restriction into account. Thus, the present work introduced a method with a quantifiable error to automatically classify and filter large amounts of data during automated digital data acquisition for landslide inventories. [ABSTRACT FROM AUTHOR]

The Federal Republic of Germany has long been among the few European countries that lack a national landslide database. Systematic collection and inventory of landslide data still has a long research history in Germany, but one focussed on the development of databases with local or regional coverage. This has changed in recent years with the launch of a database initiative aimed at closing the data gap existing at national level. The present paper reports on this project that is based on a landslide database which evolved over the last 15 years to a database covering large parts of Germany. A strategy of systematic retrieval, extraction, and fusion of landslide data is at the heart of the methodology, providing the basis for a database with a broad potential of application. The database offers a data pool of more than 4,200 landslide data sets with over 13,000 single data files and dates back to the 12th century. All types of landslides are covered by the database, which stores not only core attributes, but also various complementary data, including data on landslide causes, impacts, and mitigation. The current database migration to PostgreSQL/PostGIS is focused on unlocking the full scientific potential of the database, while enabling data sharing and knowledge transfer via a web GIS platform. In this paper, the goals and the research strategy of the database project are highlighted at first, with a summary of best practices in database development providing perspective. Next, the focus is on key aspects of the methodology, which is followed by the results of three case studies in the German Central Uplands. The case study results exemplify database application in the analysis of landslide frequency and causes, impact statistics, and landslide susceptibility modeling. Using the example of these case studies, strengths and weaknesses of the database are discussed in detail. The paper concludes with a summary of the database project with regard to previous achievements and the strategic roadmap. [ABSTRACT FROM AUTHOR]

Permanent gully channels under forest are common geomorphological features in Central European low mountain areas. In the Rehgraben/Fuchslöchergraben gully catchment in Northern Hesse, Germany the Late Pleistocene landscape formation is reconstructed based on periglacial cover beds. In addition, the Holocene landscape development and soil erosion history are investigated using anthropogenic soil sediments and alluvial fan sediments. Until now, a combination of these approaches has not been applied to a gully catchment to this extent. The distribution of the different Quaternary sediments enables the differentiation between Pleistocene and Holocene landforms. Radiocarbon and optically stimulated luminescence dating are applied to add numerical data to the relative ages of the sediments and landforms. The gully channels are oriented along Pleistocene depressions that are built up of periglacial cover beds and intercalated reworked loess. As the gully channels cut through the periglacial cover beds, especially the upper layer, the gully system is of Holocene age. At least two phases of gully erosion are identified in the alluvial fan sediments. The initial gully erosion is dated to the time span between the Late Bronze Age and Roman Times. A second gully erosion phase is dated to the 14th century and may be correlated to the severe precipitation events during this time. Gully erosion started during the Younger Holocene and is connected to human settlement and land use activity. The intense human impact hampers the application of the concept of periglacial cover beds to reconstruct landscape formation and limits it to areas where the periglacial upper layer is still preserved. [ABSTRACT FROM AUTHOR]

This paper presents a new methodology for ex post assessment of direct landslide costs for transportation infrastructures. The methodology includes tools to compile, model, and extrapolate landslide losses on different spatial scales over time. A landslide susceptibility model enables regional cost extrapolation by means of a cost figure obtained from local cost compilation for a representative case study area. On a local level, cost survey is closely linked with cost modeling, a toolset for cost estimation based on landslide databases. Cost modeling uses landslide disaster management process models (LDMMs) and cost modules to simulate and monetize cost factors for certain types of landslide damage. The landslide susceptibility model provides a regional exposure index and updates the cost figure to a cost index which describes the costs per kilometer of traffic route at risk of landslides. Both indexes enable the regionalization of local landslide losses. The methodology is applied and tested in a cost assessment for highways in the Lower Saxon Uplands, NW Germany, in the period 1980 to 2010. In this 7,400-km large mountain region, 77 km of highway is located in landslide hazard area. Annual average costs of US$52,000 per km of highway at risk of landslides are identified as cost index for a local case study area. The cost extrapolation results in annual average costs for highways in the Lower Saxon Uplands of US$4.02 million. This test application as well as a validation of selected modeling tools verifies the functionality of this methodology. [ABSTRACT FROM AUTHOR]

The major scope of the study is the assessment of landslide susceptibility of Flysch areas including the Penninic Klippen in the Vienna Forest (Lower Austria) by means of Geographical Information System (GIS)-based modelling. A statistical/probabilistic method, referred to as Weights-of-Evidence (WofE), is applied in a GIS environment in order to derive quantitative spatial information on the predisposition to landslides. While previous research in this area concentrated on local geomorphological, pedological and slope stability analyses, the present study is carried out at a regional level. The results of the modelling emphasise the relevance of clay shale zones within the Flysch formations for the occurrence of landslides. Moreover, the distribution of mass movements is closely connected to the fault system and nappe boundaries. An increased frequency of landslides is observed in the proximity to drainage lines, which can change to torrential conditions after heavy rainfall. Furthermore, landslide susceptibility is enhanced on N-W facing slopes, which are exposed to the prevailing direction of wind and rainfall. Both of the latter geofactors indirectly show the major importance of the hydrological conditions, in particular, of precipitation and surface runoff, for the occurrence of mass movements in the study area. Model performance was checked with an independent validation set of landslides, which are not used in the model. An area of 15% of the susceptibility map, classified as highly susceptible, 'predicted' 40% of the landslides. [ABSTRACT FROM AUTHOR]

Abstract: The Rhenodanubian Flysch zone of the eastern Alps of Austria is considered to be susceptible to landslides. In the study area, an undulating low mountain landscape of the eastern European Prealps, the Flysch bedrock is superimposed by Quaternary periglacial cover beds and loess. Both, the petrography of the bedrock and the soil mechanical properties of Quaternary sediments control the slope dynamics. A database compiled for the study area comprises about 200 datasets on landslide and rock fall hazards. It covers a time span between 1771 and 2007 and shows clusters between 1940 and 1943, 1965 and 1966, 1979 and 1982 as well as in 2006. The study analyses slope stability in the light of slope formation phases with respect to weathering, erosion and geology. Furthermore, geomorphological and soil–geographical methods are combined with soil–mechanical calculations. The application of the concept of periglacial cover beds facilitates the distinction between Holocene and Pleistocene landforms and slide masses in the research area. As a result, the study shows that the properties of Quaternary sediments and the occurrence of the densely bedded basal cover beds are responsible for landslide susceptibility. The variable permeability in loess layers, in contrast to that in the underlying basal cover beds, consisting mainly of marls and clayey material, is one of the fundamental controlling factors of mass movements. In a temporal context it is evident that the stability of slopes in the study area is influenced by several phases of slope formation. The synopsis of field survey, morphometrical, geotechnical as well as laboratory analyses, and slope-stability calculation, gives evidence of five morphodynamic phases that partly reoccur in an alternating pattern. After having passed all phases, the stability of the slopes studied is increased, because modified soil–mechanical properties of the slide masses become important. As a consequence, the critical slope angle is raised by 3-5°. [Copyright &y& Elsevier]

Abstract: The sediments of Holocene floodplain banks in several river catchments in the southern Cape region, South Africa, were sedimentologically investigated and radiometrically dated. The study resulted in a differentiation into two sedimentation phases. The sedimentation of the older phase starts directly above the bedrock or above coarse gravels. These sediments are composed of 2.5–3 m of interbedded sand, silt, and clay. In part, they are stratified by organic horizons and inclusions. The radiocarbon dating of numerous organic horizons as well as fossil wood shows that the sedimentation during the older phase occurred between 1215 and 875 years BP at the base, and 670 and 15 years BP at the top of this sequence. The sediments of the younger phase mainly consist of homogeneous fine sand and are at least 3 m thick, stratigraphically above the sediments of the older deposition phase. However, the sediments of the younger layer can also comprise the entire Holocene deposits situated above the current riverbed. These sediments are mainly of modern age and are partly deposits of centennial flood events. The context between the onset of sedimentation and the start of pastoral farming by settlers after AD 400, which has been archaeologically verified, supports the hypothesis that the first sedimentation phase was set off or favoured by the degradation of the natural vegetation cover as a result of livestock farming. Later, increased sedimentation as well as an increase in peak flows resulting from increased landscape degradation due to intensified pasture farming by the European settlers has to be assumed. [ABSTRACT FROM AUTHOR]

Abstract: Important controlling factors of mass movements are generally soil water and geometric-topographic terrain factors such as inclination, curvature type and degree, and the relative position of unstable slopes and embankments. In addition, various geologic parameters that have a direct or indirect connection to soil-mechanical properties of slide masses are also of importance. Some studies also emphasise tectonic parameters in the context of susceptibility to mass movements. This study considers the relevance of tectonic and structural parameters in bedrock formations for landslides in periglacial hillslope sediments on top of the bedrock. The research area is part of the southern Solling anticline, a saddle structure in the Middle Bunter Sandstone formation in northern Hesse and southern Lower Saxony (Germany). In this geologic formation, sandstone, siltstone, and mudstone are interbedded with impermeable strata. Uplift of the Solling anticline, in particular during the Quaternary, resulted in a partially intensive dissection of the Bunter Sandstone plateau into separate blocks with disrupted, tilted, and partially rotated layers. The structural conditions have an indirect impact upon landslides in the superposed hillslope sediments. Water flow along strata and joints above water impermeable strata cause water infiltration and moistening of the periglacial hillslope sediments on top of the bedrock. Mass movements are frequently linked to sites of outcrop springs and occur after long periods of rainfall. A GIS-based analysis was used to statistically evaluate possible factors controlling landslides. Factors were weighted and included in an empiric-statistical model that allows spatial description of hazard potentials due to mass movements. In addition to morphologic parameters, the structural parameters of the bedrock are of utmost importance for the occurrence of landslides. [Copyright &y& Elsevier]

The Rhenodanubian Flysch of the northern Vienna Forest is composed of various layers of sandstones, marly shales, calcareous marls, and clay shists, which are covered by Quaternary periglacial cover beds and loess deposits. This area at the margin of the eastern Alps represents an undulating landscape of the Austrian low-mountain regions. The Vienna Forest Flysch region is considered to be susceptible to landslides. Both petrography of the bedrock and soil mechanical properties of the Quaternary sediments control the current slope dynamics in the study area. In a temporal context it is evident that the stability of slopes exceeding 27◦ is controlled by a succession of several steps of slope formation. On the basis of field surveys, laboratory analyses, and slope stability modelling, results from investigations on recent landslides demonstrate five different phases of slope formation. In general, after passing these phases the stability of studied slopes is increased, due to the different soil mechanical properties of the potential sliding masses. [ABSTRACT FROM AUTHOR]

Abstract: Geomorphological mapping in the Markha valley and the northern Nimaling Mountains (Northern Zanskar Range) has revealed eight prominent glacial stages. The two oldest glaciations are marked by glacial abrasion forms as ice-scour limits and glacial benches above the lower and middle Markha valley. These glaciations probably occurred prior to the last glacial cycle. Furthermore, terminal and lateral moraines, glacial tongue basins, basal moraines and tills provide evidence for three glacial stages in the Markha and Nimaling valleys, when the equilibrium-line altitude (ELA) depression was 670–350m. The glaciations probably occurred during the LGM, the Lateglacial and the Lower Holocene as indicated by the topographic sequence, the ELA depressions and the tentative glacial stratigraphic divisions for the North Indian areas. Large moraine complexes in the vicinity of the present glaciers probably represent three glacial stages of Neoglacial and Historical glacial advances. The ELA depressions are 10–70m. The present glaciation of the Nimaling Mountains, largely restricted to north flanks and the glacier basins below, covers an area of 45–55km2. The modern ELA is calculated at 5650–5750ma.s.l. on north faces, rising to about 5900–6000ma.s.l. on south faces. In the central and southern parts of the Ayila Ridge (Western Tibet) present ELAs range from 5700 to 5800ma.s.l. on the north-facing slopes to 6000–6100ma.s.l. on southern slopes. Eight former glacier stages are preserved on the southwest flank of these mountains by lateral and terminal moraine ramparts. The ELA depressions amount to 640–950m. [Copyright &y& Elsevier]

In recent years, German laws pertaining to construction have been simplified with the goals of reducing administrative procedures and government expenditures. On the one hand, the new regulations are intended to simplify construction activities by the elimination of obstacles toward approval and by the simplification of governmental supervision procedures. On the other hand, a simplified approval process shifts the responsibility for compliance with building codes to the owners, consultants (architects, civil engineers, experts, etc.) and construction project managers. First experiences of damage to buildings show that streamlined construction approvals run the risk of neglecting basic geomorphologic and geologic fundamentals. Omissions are evident, which have led to failures at embankments and on building sites, causing considerable losses. The responsible administrations have reacted in different ways to the changed conditions, as far as they already are aware of the possible implications. In southern Lower Saxony State, the planning agencies have reacted to the growing responsibilities by attempting to determine at an early stage hazards in areas that are being developed. The practice aims to ensure that neither the planned construction activities nor the buildings themselves pose a threat for the residents. However, in the context of weighing these land-use decisions, it becomes apparent that in the future, administrative employees will have to be trained to foresee potential problems caused by the new regulations, while those affected by the decisions must receive advice on how to proceed. At the same time, latitudes and guidelines for dealing with geomorphologic hazards have to be defined. [ABSTRACT FROM AUTHOR]

Landslide impacts on infrastructure and society in the Federal Republic of Germany are associated with damage costs of about US$300 million on annual average. Despite the large overall losses due to widespread landslide activity, there is a lack of historical impact assessments, not just for Germany's low mountain areas but those of entire Central Europe as well. This paper is a collection of three case studies from Germany that seek a better understanding of landslide impacts and their economic relevance at local and regional level. The first case study investigates damage types and mitigation measures at a representative landslide site in ways that support to gain insight into historical hazard interactions with land use practices. This case history is followed by a case study dealing with fiscal cost impacts of landslide damages for an example city and the highway system of the Lower Saxon Uplands, NW Germany. In addition to a cost-burden analysis for affected public budgets, an overview of the principles of disaster financing in landslide practice is given. The third case study is focused on the conflicts of urban development in hazard areas, with an economic approach to balancing safety and public welfare interests. Each case study is based on historical data sets extracted from Germany's national landslide database. This paper presents three different case studies that in combination are a first step towards assessing landslide impacts in integrated perspective. [ABSTRACT FROM AUTHOR]

Stratified periglacial sediments extensively cover the slopes of central European low mountain areas. Periglacial cover beds and loess-like sediments as most abundant strata influence many near-surface processes, forming an important component of the Earth's critical zone. The present study focusses on the analysis of a complex sequence of periglacial slope deposits with multiple intermediate layers and intercalated slope wash sediments in order to determine and date periods of intermediate layer formation. Since luminescence dating often provides inconsistent data for cover beds, there is need to reconsider the numerical dating strategy. This study hence places stronger emphasis on numerical dating of interbedded, sufficiently bleached slope wash sediments. The gained OSL-ages are more reliable and consistent and thus, provide a temporal framework for relative dating of intermediate layer formation cycles. In combination with paleosol relics the numerical ages allowed a chronostratigraphic interpretation of Late Pleistocene paleoenvironmental dynamics and slope evolution. Our findings not only prove multiple phases of intermediate layer formation in the study area during the last glacial period but also enabled the correlation of single intermediate layers with specific time spans, including Early and Middle Weichselian as well as the Late Glacial. Remnants of the Eemian soil in the studied sequence even indicate a Saalian age for the lowermost intermediate layer. The present study shows that luminescence dating of intercalated slope wash deposits instead of cover beds is a promising numerical dating strategy for the chronostratigraphic interpretation of cover bed sequences. The findings further illustrate that complex, fanned out periglacial sediment sequences form despite their scarcity important paleoenvironmental archives for Late Pleistocene periglacial landscape dynamics in central European low mountain areas. [ABSTRACT FROM AUTHOR]

Landslide research requires consistent and widespread data. Many countries within the European Union have national landslide inventories to fulfill these demands for their respective research. However, those inventories were usually not intended to provide the technical basis for automated process and risk analyses during their design phase. The ongoing development of Germany's national landslide database offers the opportunity to do this differently. This paper introduces a landslide inventory system called WISL suitable for data handling as well as for novel automated process and risk analyses on a national scale. WISL is designated to form the technical infrastructure for a German national database. Its core consists of an open source relational database management system (PostgreSQL), standardized input and registration methods as well as integrated analyses modules, which avoid large data movement and allow for rapid risk analyses. We present proof-of-concept results of endangered infrastructure related to automated risk mappings based on topography and proximity of active landslides. The use of open source software and the application of a standardized input and data acquisition system for experts, coupled with custom analysis modules, constitutes a step toward automated risk maps by a mere 'button-press'. Future developments for the inventory lie in the field of refining and inventing analysis modules and collecting data, for which WISL provides a firm technical base. [ABSTRACT FROM AUTHOR]

Abstract: The correlation of sedimentary and pedogenetic processes in Lower Austria is difficult due to significant discontinuities and local variability in soil formation. This hampers landscape reconstruction at a regional scale. However, at a local scale distinct landscape formation processes represented by a shift from fluvial to aeolian deposition can be observed in the brickyard of Langenlois, Lower Austria. Sedimentological and mineralogical analyses in combination with palaeontological finds suggest that the fluvial deposition took place during the Middle Pleistocene. This attribution is confirmed by infra-red stimulated luminescence (IRSL) dating, which gives a minimum age of 300ka for the palaeosurface on which the fluvial sediments were deposited. This is consistent with a small faunal assemblage including Stephanorhinus sp., Dama sp. and an alcine cervid. Such a fauna is previously unknown in Austria; it indicates a Middle Pleistocene interglacial period. The low degree of weathering as well as Cryosols found in the loess sequence point to loess accumulation during the Last Glacial; the dating results (35–55ka) indicate prolonged loess deposition. No signs of pedogenesis could be found; this is surprising because in other areas this period is known for weak soil development. The lack of soil formation seems to be specific to the western part of Lower Austria, as is the complete erosion of the last glacial maximum (LGM) loess, which can not be found at Langenlois. [Copyright &y& Elsevier]

• Multi-methodological approach to a unique archive for the Holocene. • Micromorphological descriptions of complex polygenic soils and sediments. • The pedosediments are characterized and compared to international taxonomies. • Changes in soil properties are driven by parent material, relief, and land use. • These are isolated and their influence is discussed in detail. Sinkholes in the karstified Middle Keuper gypsum of Middle Franconia, Germany reveal numerous archeological findings and contain unique pedosedimentary records of landscape development and human-environment interaction during the Holocene. Mudstone-derived high clay contents result in a unique set of sedimentary and pedogenic properties of these archives in that all units exhibit vertic properties. Since the horizons have a polygenic history, detailed field and micromorphological observations, together with laboratory analyses (grain-size, color, iron-pedochemistry) are the basis for a classification of the pedosediments. 14C dating provides a chronological framework for geomorphological stability phases and thus, identified soil-forming processes. The first anthropogenic colluvial sediments of the studied archive date to the Early Bronze Age and accumulated in an initial karst depression. Water saturation caused iron reduction of these early infillings. In the pedosediments above, oxidation and iron release are largely related to changes in the parent material. Here, the soil material contains coarse silt indicating an admixture of nearby periglacial slope deposits. Furthermore, fossil root traces point to a longer time with stable conditions, which we interpret as absence of humans or at least an extended period of fallow land. The superimposed sediments from the Urnfield period are more inhomogeneous and consist of material from the eroded agricultural soils of the surrounding. The characteristics of these pedosediments point to intensified human land use. Pedogenic processes such as iron release, reduction of iron, swelling-shrinking, and short-distance translocation of clay intensively overprinted all soil sediments. In this context, micromorphology proved to be an essential tool for the characterization of polygenesis in terms of soil-forming as well as redepositional processes that lead to the formation of these complex archives. The present study reflects a multi-methodological approach to a rather disregarded type of polygenic terrestrial records. It constitutes an example for the investigation of clayey pedosediments in karstic environments under moderate climate in the frame of a prehistoric geoarcheological setting. [ABSTRACT FROM AUTHOR]