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See detailModelle zur Untersuchung von Massenbewegungen und Hangstabilität in seismischen Regionen
Mreyen, Anne-Sophie ULiege; Anja, Dufresne; Havenith, Hans-Balder ULiege

in Fachsektionstage Geotechnik - Interdisziplinäres Forum (2017, September)

Zwei von Erdrutschen betroffene Regionen in NW- und Mitteleuropa werden mittels Hangstabilitätsanalysen in Form von 3D-Geo-Modellen und numerischer 2D-Modellierung untersucht: (1) die Hockai-Störungszone ... [more ▼]

Zwei von Erdrutschen betroffene Regionen in NW- und Mitteleuropa werden mittels Hangstabilitätsanalysen in Form von 3D-Geo-Modellen und numerischer 2D-Modellierung untersucht: (1) die Hockai-Störungszone (HFZ – Hockai Fault Zone) in Ostbelgien und (2) die seismische Region Vrancea in den rumänischen Karpaten. Die Untersuchungsgebiete unterscheiden sich hinsichtlich ihrer klimatischen und seismo-tektonischen Bedingungen, sind jedoch beide von tiefsitzenden Hangbewegungen entlang aktiver bzw. inaktiver Störungszonen betroffen. Obwohl es zurzeit keinerlei eindeutige Belege massiver co-seismischer Erdrutsche in NW Europa gibt, ist die seismisch aktive HFZ in Belgien (bekannt durch das M~6-6.3 Verviers Ereignis in 1692) durch größere Massenbewegungen mit wahrscheinlichem seismischen Ursprung gekennzeichnet. Die Region Vrancea in Rumänien dagegen ist von kleineren (< 1 Mio. m³) bekannten seismischen Massenbewegungen geprägt (ausgelöst durch Erdbeben in 1940 und 1977). In solchen Regionen müssen dynamische Stabilitätsanalysen potentielles Bodenversagen durch Erdbeben berücksichtigen. Um die Massenbewegungen beider Regionen aufzuschließen, wurden verschiedene Methoden angewandt. Zu den Erkundungsmethoden zählen geotechnische, geologische und geomorphologische Untersuchungen, wie auch geophysikalische Methoden: ERT (electrical resistivity tomography), mikroseismische Bodenunruhe-Messungen (H/V-Methode), sowie SRT (seismic refraction tomography) samt Analyse seismischer Oberflächenwellen. Insbesondere die H/V-Methode ist eine zunehmend gebräuchliche Methode zur Erkundung von Hangrutschungen (1D-Abschätzung von Lockersedimentschichten, d.h. in diesem Fall von gestörten Bodenschichten). Geomechanische Eigenschaften des Hangmaterials wurden mithilfe von kleinen geotechnischen Studien (Erkundungsbohrungen, Schmidt Hammer, Strukturanalysen) und seismischen Parametern ermittelt. 3D-Geo-Modelle ermöglichen die Integration der gemessenen Daten durch Datenfusion und geostatistische Techniken. Dabei wird die Modelloberfläche anhand hochauflösender Fernerkundungsdaten (1 m LiDAR – Light Detection and Ranging) abgebildet, der Untergrund des Untersuchungsgebiets hingegen durch die Modellierung geologischer Trennflächen und Volumina. Die Geo-Modelle dienen als Basis zur Übertragung der ermittelten Daten in 2D numerische Modelle. Eine dynamische back-analysis der Untersuchungsgebiete ermöglicht die numerische Berechnung seismischer Auswirkungen auf die rutschungsanfälligen Hänge. [less ▲]

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See detailIntegrated Geological-Geophysical Models of Unstable Slopes in Seismic Areas
Mreyen, Anne-Sophie ULiege; Micu, Mihai; Onaca, Alexandru et al

in Mikos, Matjaz (Ed.) Advancing Culture of Living with Landslides (2017, May)

We will present a series of new integrated 3D models of landslide sites that were investigated in distinctive seismotectonic and climatic contexts: (1) along the Hockai Fault Zone in Belgium and (2) in ... [more ▼]

We will present a series of new integrated 3D models of landslide sites that were investigated in distinctive seismotectonic and climatic contexts: (1) along the Hockai Fault Zone in Belgium and (2) in the seismic region of Vrancea, Romania. Both sites are deep-seated failures located in more or less seismically active areas. In such areas, slope stability analyses have to take into account the possible contributions to ground failure. Our investigation methods had to be adapted to capture the deep structure as well as the physico-mechanical characteristics that influence the dynamic behaviour of the landslide body. Field surveys included electrical resistivity tomography profiles, seismic refraction profiles (analysed in terms of both seismic P-wave tomography and surface waves), ambient noise measurements to determine the soil resonance frequencies through H/V analysis, complemented by geological and geomorphic mapping. The H/V method, in particular, is more and more used for landslide investigations or sites marked by topographic relief (in addition to the more classical applications on flat sites). Results of data interpretation were compiled in 3D geological-geophysical models supported by high resolution remote sensing data of the ground surface. Data and results were not only analysed in parallel or successively; to ensure full integration of all inputs-outputs, some data fusion and geostatistical techniques were applied to establish closer links between them. Inside the 3D models, material boundaries were defined in terms of surfaces and volumes. Those were implemented in 2D and 3D numerical dynamic models (presented in a companion paper). [less ▲]

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See detailAnalysis of Migration in a Multi-Risk Context: Case of Bujumbura/Burundi
Nibigira, Léonidas ULiege; Ozer, Pierre ULiege; Havenith, Hans-Balder ULiege

in MAIER, ROBIN; REVELL, MARK (Eds.) THE AMERICAN ASSOCIATION OF GEOGRAPHERS, 2017 Annual Meeting, April 5 - 9, 2017 Boston, Massachusetts / PROGRAM (2017, April 08)

Human mobility affects land use and human density distribution. Unfortunately, this rarely takes into account the real and potential changes induced by hazards on the natural systems. Thus, migration and ... [more ▼]

Human mobility affects land use and human density distribution. Unfortunately, this rarely takes into account the real and potential changes induced by hazards on the natural systems. Thus, migration and natural hazards should be constantly analyzed through cross-sectional and global studies to reduce disastrous consequences resulting from their mutual interactions. In a multi-risk and demographic sprawl context, the study focused on the cross-analysis of human density and natural hazards in Bujumbura. The results show that migration of people should ideally be guided by knowledge of the area's sensitivity to natural hazards, taking into account other parameters such as hazards susceptibility maps and production opportunities. While the migration of people toward overcrowded centers constitutes a big challenge, it is an important asset when it concerns areas in need of manpower. It also allows the balance in relieving saturated areas, reducing human pressure on the environment. Therefore, there is a need that policymakers comply with those aspects, finding the right balance for a better situation. [less ▲]

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See detailIntegrated geological-geophysical models of unstable slopes in seismogenic areas in NW and SE Europe
Mreyen, Anne-Sophie ULiege; Micu, Mihai; Onaca, Alexandru et al

Poster (2017, April)

We will present a series of new integrated 3D models of landslide sites that were investigated in distinctive seismotectonic and climatic contexts: (1) along the Hockai Fault Zone in Belgium, with the ... [more ▼]

We will present a series of new integrated 3D models of landslide sites that were investigated in distinctive seismotectonic and climatic contexts: (1) along the Hockai Fault Zone in Belgium, with the 1692 Verviers Earthquake (M 6 - 6.5) as most prominent earthquake that occurred in that fault zone and (2) in the seismic region of Vrancea, Romania, where four earthquakes with Mw > 7.4 have been recorded during the last two centuries. Both sites present deep-seated failures located in more or less seismically active areas. In such areas, slope stability analyses have to take into account the possible contributions to ground failure. Our investigation methods had to be adapted to capture the deep structure as well as the physico-mechanical characteristics that influence the dynamic behaviour of the landslide body. Field surveys included electrical resistivity tomography profiles, seismic refraction profiles (analysed in terms of both seismic P-wave tomography and surface waves), ambient noise measurements to determine the soil resonance frequencies through H/V analysis, complemented by geological and geomorphic mapping. The H/V method, in particular, is more and more used for landslide investigations or sites marked by topographic relief (in addition to the more classical applications on flat sites). Results of data interpretation were compiled in 3D geological-geophysical models supported by high resolution remote sensing data of the ground surface. Data and results were not only analysed in parallel or successively; to ensure full integration of all inputs-outputs, some data fusion and geostatistical techniques were applied to establish closer links between them. Inside the 3D models, material boundaries were defined in terms of surfaces and volumes. Those models were used as inputs for 2D dynamic numerical simulations completed with the UDEC (Itasca) software. For some sites, a full back-analysis was carried out to assess the possibility of a seismic triggering of the landslides. [less ▲]

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See detailImmersive visualization of geophysical data
Cerfontaine, Philippe ULiege; Mreyen, Anne-Sophie ULiege; Havenith, Hans-Balder ULiege

in Immersive visualization of geophysical data (2016, December)

In this application paper we’ll explain the work flow we use to create immersive visualizations and spatial interaction for geophysical data with a head mounted device (HMD). The data that we analyze ... [more ▼]

In this application paper we’ll explain the work flow we use to create immersive visualizations and spatial interaction for geophysical data with a head mounted device (HMD). The data that we analyze consists of two dimensional geographical map data and raw geophysical measurements with devices like seismometers, Electrical Resistivity Tomography (ERT) and seismic tomography profiles as well as other geophysical and geoscientific data. We show the tool chain that we use while explaining the choices that we made along the way. The technical description will be followed by a brief assessment of the added benefit of rendering our data in virtual reality (VR). After the technical description we conclude this paper with some outlook on the (likely) future use of VR in geosciences. [less ▲]

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See detailLa responsabilité climatique dans les défis urbains contemporains: évaluation et mise en contexte pour la ville de Bujumbura, Burundi
Nibigira, Léonidas ULiege; Ozer, Pierre ULiege; Havenith, Hans-Balder ULiege

in Ozer, Pierre; Ginesu, Sergio; Ozer, André (Eds.) La géographie physique et les risques de pertes et préjudices liés aux changements climatiques - Livre de résumés (2016, May 19)

A Bujumbura, la capitale du Burundi, les préjudices liés aux risques naturels deviennent de plus en plus une réalité quotidienne. Les cas les plus ressentis sont ceux liés aux inondations, aux glissements ... [more ▼]

A Bujumbura, la capitale du Burundi, les préjudices liés aux risques naturels deviennent de plus en plus une réalité quotidienne. Les cas les plus ressentis sont ceux liés aux inondations, aux glissements de terrain et à l'érosion. Les épidémies relatives aux conditions sanitaires précaires deviennent de plus en plus récurrentes. [...] [less ▲]

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See detailSpatial Analysis of the Landslide Risk in the Cameroon Volcanic Line (CVL)
Mukenga, Williams ULiege; Havenith, Hans-Balder ULiege; Medjo Eko, Robert et al

Poster (2016, May 12)

Landslides are recognized as important geomorphologic process due to the role they play in the development of hill slopes in mountainous regions, and to related socio-economic consequences. There are many ... [more ▼]

Landslides are recognized as important geomorphologic process due to the role they play in the development of hill slopes in mountainous regions, and to related socio-economic consequences. There are many causes of landslides and their distribution varies with the changing conditioning factors. Slope stability depends on a number of causative factors and the knowledge of these variables can help to predict the type of landslide expected in the future. In this study, past landslide activity and triggering factors will be used to assess mass movement hazards along the Cameroon Volcanic Line (CVL). Spatial aspects will be studied in terms of landslide susceptibility maps that are important for development planning and disaster management. The current synthesis of landslide susceptibility map at regional scale is based on a literature review to inventory passed mass movement impacts, on the detection of landslide features from Google Earth imagery, combined with spatial analysis using Geographical Information Systems (GIS) and remote sensing. One of the most critical stages in landslide susceptibility mapping is the selection of landslide pre-conditioning, conditioning and triggering factors and weighting of the selected causative factors in accordance to their influence on slope stability. Google earth helps for delineating past (but recent) and present landslide activity whereas GIS is suitable when deriving static factors (slope aspect and surface curvature) and time-dependent factors (annual precipitation and changing groundwater table level) that are needed to produce landslide susceptibility maps. Landslide susceptibility mapping is based on the assumption that future landslides will occur under similar circumstances as past and present mass movements. Different methods, including the weight of evidence methods, are used for landslide susceptibility mapping along the Cameroon Volcanic line, as the area is known to be highly susceptible to landslide occurrences. [less ▲]

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See detailA new classification of earthquake-induced landslide event sizes based on seismotectonic, topographic, climatic and geologic factors
Havenith, Hans-Balder ULiege; Torgoev, Almazbek ULiege; Braun, Anika et al

in Geoenvironmental Disasters (2016), 3(6), 2-24

Background This paper reviews the classical and some particular factors contributing to earthquake-triggered landslide activity. This analysis should help predict more accurately landslide event sizes ... [more ▼]

Background This paper reviews the classical and some particular factors contributing to earthquake-triggered landslide activity. This analysis should help predict more accurately landslide event sizes, both in terms of potential numbers and affected area. It also highlights that some occurrences, especially those very far from the hypocentre/activated fault, cannot be predicted by state-of-the-art methods. Particular attention will be paid to the effects of deep focal earthquakes in Central Asia and to other extremely distant landslide activations in other regions of the world (e.g. Saguenay earthquake 1988, Canada). Results The classification of seismically induced landslides and the related ‘event sizes’ is based on five main factors: ‘Intensity’, ‘Fault factor’, ‘Topographic energy’, ‘Climatic background conditions’, ‘Lithological factor’. Most of these data were extracted from papers, but topographic inputs were checked by analyzing the affected region in Google Earth. The combination and relative weight of the factors was tested through comparison with well documented events and complemented by our studies of earthquake-triggered landslides in Central Asia. The highest relative weight (6) was attributed to the ‘Fault factor’; the other factors all received a smaller relative weight (2–4). The high weight of the ‘Fault factor’ (based on the location in/outside the mountain range, the fault type and length) is strongly constrained by the importance of the Wenchuan earthquake that, for example, triggered far more landslides in 2008 than the Nepal earthquake in 2015: the main difference is that the fault activated by the Wenchuan earthquake created an extensive surface rupture within the Longmenshan Range marked by a very high topographic energy while the one activated by the Nepal earthquake ruptured the surface in the frontal part of the Himalayas where the slopes are less steep and high. Finally, the calibrated factor combination was applied to almost 100 other earthquake events for which some landslide information was available. This comparison revealed the ability of the classification to provide a reasonable estimate of the number of triggered landslides and of the size of the affected area. According to this prediction, the most severe earthquake-triggered landslide event of the last one hundred years would actually be the Wenchuan earthquake in 2008 followed by the 1950 Assam earthquake in India – considering that the dominating role of the Wenchuan earthquake data (including the availability of a complete landslide inventory) for the weighting of the factors strongly influences and may even bias this result. The strongest landslide impacts on human life in recent history were caused by the Haiyuan-Gansu earthquake in 1920 – ranked as third most severe event according to our classification: its size is due to a combination of high shaking intensity, an important ‘Fault factor’ and the extreme susceptibility of the regional loess cover to slope failure, while the surface morphology of the affected area is much smoother than the one affected by the Wenchuan 2008 or the Nepal 2015 earthquakes. Conclusions The main goal of the classification of earthquake-triggered landslide events is to help improve total seismic hazard assessment over short and longer terms. Considering the general performance of the classification-prediction, it can be seen that the prediction either fits or overestimates the known/observed number of triggered landslides for a series of earthquakes, while it often underestimates the size of the affected area. For several events (especially the older ones), the overestimation of the number of landslides can be partly explained by the incompleteness of the published catalogues. The underestimation of the extension of the area, however, is real – as some particularities cannot be taken into account by such a general approach: notably, we used the same seismic intensity attenuation for all events, while attenuation laws are dependent on regional tectonic and geological conditions. In this regard, it is likely that the far-distant triggering of landslides, e.g., by the 1988 Saguenay earthquake (and the related extreme extension of affected area) is due to a very low attenuation of seismic energy within the North American plate. Far-distant triggering of landslides in Central Asia can be explained by the susceptibility of slopes covered by thick soft soils to failure under the effect of low-frequency shaking induced by distant earthquakes, especially by the deep focal earthquakes in the Pamir – Hindukush seismic region. Such deep focal and high magnitude (> > 7) earthquakes are also found in Europe, first of all in the Vrancea region (Romania). For this area as well as for the South Tien Shan we computed possible landslide event sizes related to some future earthquake scenarios. [less ▲]

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See detailLandslides' mechanism and evolution in the western Rwanda
Draidia, Salah ULiege; El Ouahabi, Meriam ULiege; Dewitte, Olivier et al

Scientific conference (2016, January 27)

Landslides' mechanism and evolution in the western Rwanda Salah DRAIDIA1,*, Meriam EL OUAHABI1, Olivier DEWITTE2, Nathalie Fagel1, Hans Balder HAVENITH1 1 Institution 1 University of Liège Department of ... [more ▼]

Landslides' mechanism and evolution in the western Rwanda Salah DRAIDIA1,*, Meriam EL OUAHABI1, Olivier DEWITTE2, Nathalie Fagel1, Hans Balder HAVENITH1 1 Institution 1 University of Liège Department of Geology Street, n° 4000 Liège Belgium 2 Institution 2 Royal Museum of Central Africa Department of Geomogy Tervuren Belgium *Corresponding author: sdraidia@gmail.com, Département de Géologie, Quartier Agora, Allée du six Août, 14, B- 4000 LIEGE (Sart Tilman) Tel +32 0497351617 Keywords: mass movement, landslides, landscape evolution, geohazard,. Abstract The mass movement, and especially the instability of the soil and rocks, play a significant role in the changing aspect and the evolution of the landscape worldwide and particularly in tropical region. In Central Africa the landslides and others kind of instabilities are very frequent, important and represent a real threat for both population and economy. The case of Rwanda is remarkable, this country which is known as the country of thousand hills, is rich of various and very complex morphology caracterized by very steep slopes crossed by a dense network of watercourse, powered by a considerable amount of precipitation distributed in two wet seasons. The growing economy of the country brings a lot of project of infrastructures and mines and quarries exploitation (embankments and cuttings) which have a strong impact on the triggering of huge instabilities and so the modification of landscape. These instabilities and the intense activity of the rivers and streams could be considered as the engine who control the shaping and the remodeling of the landform. To understand the evolution process of these instabilities, and then the landscape change we started by the mapping of the instabilities using satellite images and then we went on the field to validate the inventory to identify the morphological aspect of the terrain, to refine our knowledge of the geological nature of the materials by sedimentological analyses on selected samples, and of course to try to better know the impact of the rock's weathering process leading to the constant modification of the landform. The computer-based quantitative analyses using GIS's data processing, were carried out to help to understand the distribution of the instabilities and the geomorphological phenomena observed to better connect and explain the whole information collected. The aim of the study is to bring in more than the mapping of instabilities a response about the process and the evolution of the instabilities and the factors impacting the phenomenon. [less ▲]

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See detail2D dynamic studies combined with the surface curvature analysis to predict Arias Intensity amplification
Torgoev, Almazbek ULiege; Havenith, Hans-Balder ULiege

in Journal of Seismology (2016)

A 2D elasto-dynamic modelling of the pure topographic seismic response is performed for six models with a total length of around 23.0 km. These models are reconstructed from the real topographic settings ... [more ▼]

A 2D elasto-dynamic modelling of the pure topographic seismic response is performed for six models with a total length of around 23.0 km. These models are reconstructed from the real topographic settings of the landslide-prone slopes situated in the Mailuu-Suu River Valley, Southern Kyrgyzstan. The main studied parameter is the Arias Intensity (Ia, m/sec), which is applied in the GIS-based Newmark method to regionally map the seismically-induced landslide susceptibility. This method maps the Ia values via empirical attenuation laws and our studies investigate a potential to include topographic input into them. Numerical studies analyse several signals with varying shape and changing central frequency values. All tests demonstrate that the spectral amplification patterns directly affect the amplification of the Ia values. These results let to link the 2D distribution of the topographically amplified Ia values with the parameter called as smoothed curvature. The amplification values for the low-frequency signals are better correlated with the curvature smoothed over larger spatial extent, while those values for the high-frequency signals are more linked to the curvature with smaller smoothing extent. The best predictions are provided by the curvature smoothed over the extent calculated according to Geli’s law. The sample equations predicting the Ia amplification based on the smoothed curvature are presented for the sinusoid-shape input signals. These laws cannot be directly implemented in the regional Newmark method, as 3D amplification of the Ia values addresses more problem complexities which are not studied here. Nevertheless, our 2D results prepare the theoretical framework which can potentially be applied to the 3D domain and, therefore, represent a robust basis for these future research targets. [less ▲]

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See detailOccurrences and genesis of palygorskite/ sepiolite and associated minerals in the Barzaman formation, United Arab Emirates
Draidia, Salah ULiege; El Ouahabi, Meriam ULiege; Daoudi, Lahcen et al

in Clay Minerals (2016), 51(763–779),

: The Barzaman Formation exposed in the United Arab Emirates was deposited as a series of fluvial sediment sequences lying along the western margin of the Hajar Mountains, part of the Oman–UAE ophiolite ... [more ▼]

: The Barzaman Formation exposed in the United Arab Emirates was deposited as a series of fluvial sediment sequences lying along the western margin of the Hajar Mountains, part of the Oman–UAE ophiolite. This formation consists of a sequence of rocks dominated by variably cemented and altered conglomerates comprising calcareous siltstones and calcareous clays deposited during the Miocene to Pliocene undera humid climate. The conglomerates are composed largelyof ultramafic and lesser-mafic clasts. The present study was undertaken in order to understand the occurrence and genesis of palygorskite and sepiolite in relation to the environmental changes including evaporitic and sabkha environments. Sediments were collected from two trenches and a drill hole of ∼22 m depth. Samples were analysed by optical petrograpy, X-ray diffraction and scanning electron microscopy. Pedogenesis occurred at the deeper level in well cemented conglomerate which constitutes the hard crust. Post-depositional erosion started in marine phreatic or vadose zones as shown by the neoformation of serpentine from the weathering of olivine as well as of calcite and dolomite. Neoformation of palygorskite, sepiolite, dolomite and halite occurred under evaporitic conditions on calcareous silty clay facies. Relatively hot, vadose and oxidizing environmental conditions affected the calcareous siltstone facies leading to the genesisof dolomite andpalygorskite by directprecipitation fromsolution rich inCa, Mg, Al,Feand Si ions. [less ▲]

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See detailPreliminary assessment for the use of VORIS as a tool for rapid lava flow simulation at Goma Volcano Observatory, Democratic Republic of the Congo
Syavulisembo, A. M.; Havenith, Hans-Balder ULiege; Smets, B et al

in Natural Hazards & Earth System Sciences (2015)

Assessment and management of volcanic risk are important scientific, economic, and political issues, especially in densely populated areas threatened by volcanoes. The Virunga volcanic province in the ... [more ▼]

Assessment and management of volcanic risk are important scientific, economic, and political issues, especially in densely populated areas threatened by volcanoes. The Virunga volcanic province in the Democratic Republic of the Congo, with over 1 million inhabitants, has to cope permanently with the threat posed by the active Nyamulagira and Nyiragongo volcanoes. During the past century, Nyamulagira erupted at intervals of 1–4 years – mostly in the form of lava flows – at least 30 times. Its summit and flank eruptions lasted for periods of a few days up to more than 2 years, and produced lava flows sometimes reaching distances of over 20 km from the volcano. Though most of the lava flows did not reach urban areas, only impacting the forests of the endangered Virunga National Park, some of them related to distal flank eruptions affected villages and roads. In order to identify a useful tool for lava flow hazard assessment at Goma Volcano Observatory (GVO), we tested VORIS 2.0.1 (Felpeto et al., 2007), a freely available software (http://www.gvb-csic.es) based on a probabilistic model that considers topography as the main parameter controlling the lava flow propagation. We tested different parameters and digital elevation models (DEM) – SRTM1, SRTM3, and ASTER GDEM – to evaluate the sensitivity of the models to changes in input parameters of VORIS 2.0.1. Simulations were tested against the known lava flows and topography from the 2010 Nyamulagira eruption. The results obtained show that VORIS 2.0.1 is a quick, easy-to-use tool for simulating lava-flow eruptions and replicates to a high degree of accuracy the eruptions tested when input parameters are appropriately chosen. In practice, these results will be used by GVO to calibrate VORIS for lava flow path forecasting during new eruptions, hence contributing to a better volcanic crisis management. [less ▲]

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See detailLANDSLIDES IN CENTRAL AFRICA: FROM DEFORMATION MECHANISMS TO EVOLUTION PROCESSES – CASES STUDIES FROM RWANDA AND BURUNDI
Draidia, Salah ULiege; Ndahimana, Hamuli; Habimana, Christophe et al

Scientific conference (2015, July)

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See detailRadar remote sensing observations to monitor landslides and prepare inventories for hazard assessment
Schlögel, Romy; Havenith, Hans-Balder ULiege; Malet, Jean-Philippe et al

Scientific conference (2015, May)

Abstract: The creation of a landslide inventory encompassing multi-temporal information needs high quality and high-resolution data source as well as a good knowledge of the field. Visual image ... [more ▼]

Abstract: The creation of a landslide inventory encompassing multi-temporal information needs high quality and high-resolution data source as well as a good knowledge of the field. Visual image interpretation and field surveys are the prevailing methods for landslide inventory mapping while remote sensing techniques have become a widely used source of information for measuring the topography and deformation of the Earth surface (e.g. Berardino et al., 2002). Semi-automatic image analysis methods based on remote sensing techniques are proposed but their quality lacks behind the expert mappings (Guzzetti et al., 2012). Advance processing of SAR images have proven their ability for: (1) landslide detection and mapping (Farina et al., 2006; Cascini et al., 2009; Guzzetti et al., 2012), (2) process monitoring (Hilley et al., 2004; Zhao et al., 2012), (3) hazard assessment (e.g. Nikolaeva et al., 2014) and (4) risk management (Bardi et al., 2014). ... [less ▲]

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See detailThe Kambarata 2 blast-fill dam, Kyrgyz Republic: blast event, geophysical monitoring and dam structure modelling
Havenith, Hans-Balder ULiege; Torgoev, Isakbek; Torgoev, Almazbek ULiege et al

in Geoenvironmental Disasters (2015), 2(1), 1-15

Abstract Background The blast-and earth-fill dam of the Kambarata 2 hydropower station is situated in the seismically active Central Tien Shan region of the Kyrgyz Republic. More than 70% of the dam ... [more ▼]

Abstract Background The blast-and earth-fill dam of the Kambarata 2 hydropower station is situated in the seismically active Central Tien Shan region of the Kyrgyz Republic. More than 70% of the dam volume was produced during a blast event on December 22, 2009. In 2010– 2011, dam construction was completed after earth filling on top of the blasted material and installing concrete and clay screens together with bentonite grouts. A geophysical survey had been completed in 2012–2013, mainly to monitor the resistivities inside the dam. ... [less ▲]

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See detailSeismic hazard assessment of the Kivu rift segment based on a new sismo-tectonic zonation model (Western Branch of the East African Rift system)
Havenith, Hans-Balder ULiege; Delvaux, Damien

in EGU General Assembly Conference Abstracts (2015, April)

In the frame of the Belgian GeoRisCA multi-risk assessment project focused on the Kivu and Northern Tanganyika Region, a seismic hazard map has been produced for this area. It is based on a on a recently ... [more ▼]

In the frame of the Belgian GeoRisCA multi-risk assessment project focused on the Kivu and Northern Tanganyika Region, a seismic hazard map has been produced for this area. It is based on a on a recently re-compiled catalogue using various local and global earthquake catalogues. The use of macroseismic epicenters determined from felt earthquakes allowed to extend the time-range back to the beginning of the 20th century, thus spanning about 100 years. The magnitudes have been homogenized to Mw and the coherence of the catalogue has been checked and validated. The seismo-tectonic zonation includes 10 seismic source areas that have been defined on the basis of the regional geological structure, neotectonic fault systems, basin architecture and distribution of earthquake epicenters... [less ▲]

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See detailLandslide Susceptibility Mapping with Data Mining Methods—a Case Study from Maily-Say, Kyrgyzstan
Braun, A.; Fernandez-Steeger, T.; Havenith, Hans-Balder ULiege et al

in Engineering Geology for Society and Territory - Volume 2: Landslide Processes (2015)

Abstract: Multiple factors, such as geology, high mountain topography, seismic activity, climatic conditions and mining activities cause significant landslide hazard in the region around Maily-Say ... [more ▼]

Abstract: Multiple factors, such as geology, high mountain topography, seismic activity, climatic conditions and mining activities cause significant landslide hazard in the region around Maily-Say, Kyrgyzstan. To assess the landslide susceptibility a database containing landslide information and geological, morphological and hydrological parameters associated with landslide occurrence was established and analyzed with different data mining algorithms. The most promising results were achieved with an Artificial Neural ... [less ▲]

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See detailGIS-Based Landslide Susceptibility Mapping in the Great Lakes Region of Africa, Case Study of Bujumbura Burundi
Nibigira, Léonidas ULiege; Draidia, Salah ULiege; Havenith, Hans-Balder ULiege

in Engineering Geology for Society and Territory - Volume 2: Landslide Processes (2015)

Abstract: Landslides in Central Africa represent a constant threat to the population. The present work took its motivation from the increasing number of recorded incidents in recent times. It is focused ... [more ▼]

Abstract: Landslides in Central Africa represent a constant threat to the population. The present work took its motivation from the increasing number of recorded incidents in recent times. It is focused on the analysis of mass movements in a regional context. Remote sensing based on the use of satellite images (Pleiades images of 2011) and aerial photographs (1957, 1958 and 1981) allowed us to identify instabilities at different scales. The study of these mass movements and the characterization of the processes governing ... [less ▲]

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See detailHazard and Risk Related to Earthquake-Triggered Landslides
Havenith, Hans-Balder ULiege; Fan, X.; Torgoev, A.

in Engineering Geology for Society and Territory - Volume 2: Landslide Processes (2015)

Abstract This paper first analyses how important earthquake-induced landslide hazards are compared to other geohazards at world-wide scale. Further, we will outline where these hazards may have the ... [more ▼]

Abstract This paper first analyses how important earthquake-induced landslide hazards are compared to other geohazards at world-wide scale. Further, we will outline where these hazards may have the strongest impacts—at regional and local scale. In this regard, we consider the short-and long-term effects of geological, tectonic, climatic and morphological conditions. Hazard and risk related to these processes will also be analysed on the basis of a series of case histories: eg, the 1920 Haiyuan earthquake-landslide disaster in China. A ... [less ▲]

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See detailTien Shan geohazards database: Earthquakes and landslides
Havenith, Hans-Balder ULiege; Strom, Alexander; Torgoev, Isakbek et al

in Geomorphology (2015), 249

In this paper we present new and review already existing landslide and earthquake data for a large part of the Tien Shan, Central Asia. For the same area, only partial databases for sub-regions have been ... [more ▼]

In this paper we present new and review already existing landslide and earthquake data for a large part of the Tien Shan, Central Asia. For the same area, only partial databases for sub-regions have been presented previously. They were compiled and new data were added to fill the gaps between the databases. Major new inputs are products of the Central Asia Seismic Risk Initiative (CASRI): a tentative digital map of active faults (even with indication of characteristic or possible maximum magnitude) and the earthquake catalogue of Central Asia until 2009 that was now updated with USGS data (to May 2014). The new compiled landslide inventory contains existing records of 1600 previously mapped mass movements and more than 1800 new landslide data. Considering presently available seismo-tectonic and landslide data, a target region of 1200 km (E–W) by 600 km (N–S) was defined for the production of more or less continuous geohazards information. This target region includes the entire Kyrgyz Tien Shan, the South-Western Tien Shan in Tajikistan, the Fergana Basin (Kyrgyzstan, Tajikistan and Uzbekistan) as well as the Western part in Uzbekistan, the North-Easternmost part in Kazakhstan and a small part of the Eastern Chinese Tien Shan (for the zones outside Kyrgyzstan and Tajikistan, only limited information was available and compiled)... [less ▲]

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