Occurrence Of Mass Movements Research Articles

Geomorphologycal Study for Flood and Mass Movement Occurrence at Parang Sub Village, Paranggupito District, Wonogiri Regency

The aim of this study are knowing factors that impacts to flood and mass movement hazard at karst region. Area of this study are covering Parang Sub Village, Ngasem, Paranggupito District, Wonogiri Regency. To achieve this objective, geomorphic approaches (static, as well as dynamic environmental geomorphology) were analyzed, using survey and secondary data collection. Results from this study are describe that Parang is a karst depression and had water accumulated from Parang boundaries area as upper landform. Mass movement at study area is caused by saturation of soil by water after rainfall. Supported by steep slope impact sliding mass movement. Based on the priority, to change the water running direction and will not concentrate to Parang Depresion, there are need the water-massbank stability. This bank will prevent the soil mass to stable.

Distribution and spatial analysis of rockslides failures in the Icelandic Westfjords: first results

Rockslides are numerous in the Icelandic Westfjords. In this study, the large visible rockslides have been inventoried in a first stage, by observation of aerial images and subsequent photo-interpretation. A total of 186 rockslides has been recorded and in a second stage, their distribution has been studied, using Geographic Information Systems and statistical methods like Kernel Density Estimator (KDE). The relief of the studied area is closely related with the glacial and interglacial periods. Rockslides are mostly concentrated close to the coast, where the relief is dominantly shaped by glaciers exposing high slopes, while the inner part mainly constituted of plateaux is not prone to mass movements. Nevertheless, the statistical analysis does not show a strong correlation between slope gradient and rockslides concentration, as the null hypothesis is not rejected. Other causes already mentioned by several authors are consistent with the location of rockslides, such as favourable dip or mass movement occurrence in the Tertiary basalts. These elements cannot explain the spatial distribution of rockslides in the Westfjords by themselves, at a regional scale. The deglaciation pattern might provide an explanation for this spatial distribution, even without precise dating. This work provides a new database where commonly claimed triggers do not provide a satisfactory explanation to the spatial distribution of rockslides in the Icelandic Westfjords.

Large-scale seismically-induced mass-movements in a former glacial lake basin: Lake Témiscouata, northeastern Appalachians (eastern Canada)

Disturbed lacustrine deposits of eastern Canada have been associated with past seismic events in the intraplate Western Québec Seismic Zone (WQZ) and the Charlevoix–Kamouraska Seismic Zone (CKSZ). With five major earthquakes that occurred during historical times and hundreds of minor earthquakes, the CKSZ is the most active seismic zone in eastern Canada. Here we present new high-resolution multibeam bathymetric, subbottom profiler and sediment core data collected in Lake Témiscouata, southeastern Québec, the largest lake located within the influence of the CKSZ. The occurrence of mass-movements in the highly cohesive glaciolacustrine deposits of the lake produced a peculiar lacustrine landscape consisting of steep slide scars and residual mounds and very narrow residual crests. Our data indicate that postglacial times were marked by recurrent seismically-induced mass-movement events that cannot be individually identified in the sedimentary record due to the highly disturbed stratigraphy of the lake and to the absence of significant postglacial background sediments between events. The most recent recorded mass-movement is a distinct debris flow sediment layer on the lake floor that was deposited at ~1300calBP, very shortly after a distinct large-scale mass-movement event observed across the entire lake basin. The presence of silt layers in gyttja overlying these disturbed units suggests that the region was affected by other seismic events following this event, although no MMDs could be directly related to these layers.

The effect of forest fire on mass movement in Lebanese mountainous areas

Mass movements are major hazards that threaten natural and human environments. In Lebanon, the occurrence of mass movements increased by almost 60% between 1956 and 2008. Forest fire has emerged as an additional hazard: it destroyed over 25% of Lebanon’s forests in a period less than 40 years. This paper investigates the potential effect of forest fire on the occurrence of mass movements in the Damour and Nahr Ibrahim watersheds of Lebanon. Mass movement and forest fire inventory maps were produced through remote sensing using aerial and satellite images. Forest fire was included as an additional factor in mass movement induction, and its effect was quantified from Landsat images through the normalised burn ratio (NBR) index. A field study was conducted to substantiate the mass movement inventory and NBR maps. Following the standardisation of the effect factors into layers using geographic information systems, the weight factor of each layer for inducing mass movements was evaluated using the modified InfoVal method, and a mass movement susceptibility map was generated. Exceeded only by changes in land cover, the NBR produced the highest weights, making forest fire burn severity the second highest factor influencing mass movement occurrence in the study areas.

Effect of forest harvesting on hydrogeomorphic processes in steep terrain of central Japan

Forest harvesting activities affect various hydrogeomorphic processes in forest terrain, including increases in occurrence of mass movements (i.e., landslides and debris flows), and changes in sediment transport rate in channels. Thus, the influence of harvesting on these processes needs to be assessed to protect aquatic ecosystems. In steep terrain with frequent mass movement, relationships between rainfall magnitude and frequency of mass movements associated with forest harvesting are needed to develop improved strategies for disaster prevention. We examined the effects of forest harvesting on the frequency of mass movements in the steep Sanko catchment (central Japan) using aerial photographs for six different years covering 1976 to 2003. We also investigated the spatial distribution of sediment stored in the system as well as sediment transport rate in selected subcatchments by field surveys. Landslides occur during moderate rainfall events (return period of daily rainfall<10years) in younger forests (<25years after harvesting), whereas the threshold magnitude of rainfall for landslides is higher in older forests (>25years after harvesting). The occurrence of mass movements substantially altered the volume of sediment storage in the channel that links sediment supply from hillslopes with sediment yield downstream. However, the volume and spatial distribution of sediment deposits in headwater channels were not clearly related to forest age because of the redistribution and evacuation of sediment by debris flows. Bedload transport rate was highly affected by sediment storage volume, whereas suspended sediment concentration was affected by the area of exposed sediment along channels that was carved by debris flows. Thus, the effect of harvesting on hydrogeomorphic processes cannot be estimated simply by the elapsed time after forest harvesting; rainfall magnitude and the history of mass movements need to be considered to better understand these linkages.

GIS-based assessment of landslide susceptibility on the base of the Weights-of-Evidence model

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.

Spatiotemporal sequence of Himalayan debris flow from analysis of high‐frequency seismic noise

During the 2003 summer monsoon, the Hi‐CLIMB seismological stations deployed across the Himalayan Range detected bursts of high‐frequency seismic noise that lasted several hours to days. On the basis of the cross correlation of seismic envelopes recorded at 11 stations, we show that the largest transient event on 15 August was located nearby a village partially destroyed on that day by a devastating debris flow. This consistency in both space and time suggests that high‐frequency seismic noise analysis can be used to monitor debris flow generation as well as the evacuation of the sediment. A systematic study of one year of seismic noise, focusing on the detection of similar events, provides information on the spatial and temporal occurrence of mass movements at the front of the Himalayas. With a 50% probability of occurrence of a daily event, a total of 46 debris flows are seismically detected. Most of them were generated in regions of steep slopes, large gullies, and loose soils during the 2003 summer monsoon storms. These events are compared to local meteorological data to determine rainfall thresholds for slope failures, including the cumulative rainfall needed to bring the soil moisture content to failure capacity. The inferred thresholds are consistent with previous estimates deduced from soil studies as well as sediment supply investigations in the area. These results point out the potential of using seismic noise as a dedicated tool for monitoring the spatiotemporal occurrence of landslides and debris flows on a regional scale.

Investigating the transferability of statistical disposition models for slope-type debris flows

Statistical disposition models are used both in geomorphology and in natural hazards research to spatially predict the occurrence of mass movements, other geomorphic processes or landforms. This is achieved by establishing some statistical relationship between an inventory of mapped occurrences and relevant geofactor maps. Statistical approaches rely, among others, on the assumption that future events will take place under the same conditions as they did in the past. In the present paper, the Certainty Factor (one of the favourability functions) is used to quantify the association of debris flow initiation sites with the geofactors landcover, slope and CIT index in three alpine study areas. The transferability of the models, i.e. their applicability to other study areas, is investigated using a comparison of model results (CF parameters) from different study areas and an extensive cross-validation. It is shown that, in similar study areas, the model parameters are generally very similar, indicating that the geofactors represent well enough the relevant conditions and processes that lead to debris flow initiation. The cross-validation is generally successful, independent of the similarity of the area for which the model has been established and the target area. Therefore, it can be concluded that statistical disposition models such as the CF model are, in principle, transferable between study areas. Nevertheless, some critical issues such as data quality have to be kept in mind when trying to apply a model to another study area.

A laboratory study on groundwater quality and mass movement occurrence

In this study, soil samples collected from the sides of two streams with high debris flow potential at Shenmu and Fengchiou village in Nantou County, Taiwan, were used for seepage tank tests in the laboratory. While the tests were being conducted, observations were made to investigate the relationships among displacement of the slope, quality of the seepage water and occurrence of mass movement. The results showed that according to the change rate, displacement could be divided into two stages, namely, the initial failure displacement stage and primary failure displacement stage. While the displacement of the slope was in primary failure displacement stages, the probability of slope failure became much higher. Before general slope failure, electrical conductivity (EC) and sulfate ion (SO4 2−) concentration of the seepage water increased significantly. The time when EC of the seepage water started to increase rapidly was much earlier than that when displacement of the slope started to increase significantly. Therefore, from the hazard mitigation view, there will be a longer time for response if EC of the seepage water was monitored.

Os problemas da cartografia dos riscos naturais. Contributos para a definição da susceptibilidade geomorfológica a partir da observação de vários movimentos de vertente ocorridos no norte de Portugal

A produção de cartografia dos riscos naturais relativos a movimentos de vertente depende, em larga medida, do conhecimentos dos factores permanentes. O Inverno de 2000/2001 constitui uma referência importante na definição desses factores uma vez que em várias áreas do Norte de Portugal ocorreram vários tipos de movimentos de vertente, em condições geográficas muito diversificadas. O estudo desses movimentos permite alargar o conhecimento sobre as suas condições de ocorrência e, dessa forma, contribuir para a definição dos critérios de construção da cartografia da susceptibilidade geomorfológica. Quer optemos pela cartografia directa ou indirecta na zonação dos riscos naturais, consideramos que não é possível fazê-lo sem que os critérios que presidem à sua elaboração sejam definidos a partir do estudo das situações de crise ocorridas. Neste texto são apresentados vários movimentos de vertente no norte de Portugal e são analisados os factores geográficos responsáveis pela sua ocorrência. Na apresentação que é feita dá-se importância aos aspectos que se relacionam com a intervenção humana e questiona-se o papel que a cartografia da susceptibilidade geomorfológica poderá ter no ordenamento e planeamento do território.

Study of mass movements along Kundasang Road, Sabah

The study of mass movements has long been regarded as one of the most important aspects which should be implemented in road construction in Sabah. Mass movements is a general term for a variety of earth processes by which large masses of rock and/or earth material spontaneously move downward either slowly or quickly by gravitation. This paper will focus on the study of Kundasang Road, one ofthe most vulnerable to mass movements occurrence in West Coast Sabah. Mass movements in the study area landslide, creep, rock slide and rock fall. Several factors contribute to the occurrence of mass movements and these are categorized into geological, geomorphological, climatological and anthropological factors. Consideration of these hazards must be taken into account in development planning to counter their disruptive effects. '

Classic and new dating methods for assessing the temporal occurrence of mass movements

Establishing landslide chronologies is essential both for understanding causes of mass movements as part of fundamental geomorphological research, and for the assessment of landslide hazards as part of applied geomorphology. We discuss the applicability of different methods for determining landslide chronologies, frequencies and dynamics in relation to the type of material being dated, sampling location and type of mass movement. The emphasis is on the possibilities and limitations of the different dating methods. Established methods such as radiocarbon dating, lichenometry and dendrochronology are briefly discussed. The paper focuses, however, on (1) new analytical techniques like Accelerator Mass Spectrometry (AMS), Thermally Ionising Mass Spectrometry (TIMS) and laser fusion, which have led to significant improvements of established dating methods and on (2) new dating methods like Optically-Stimulated-Luminescence (OSL) dating and Alpha-Recoil-Track (ART) dating.

Late Quaternary climate changes and mass movement frequency and magnitude in the Cantabrian region, Spain

A reconstruction of Holocene climate changes in the Cantabrian region, based on pollen records and on complementary sedimentological, geomorphological, archaeological and oxygen isotope data is presented. The climate model thus proposed has been tested obtaining new sediment records and dating sixteen additional samples. The distribution and relative chronology of slope movements in a study area are presented. Eleven new dates have been obtained for landslide and flow deposits and a correlation between occurrence of mass movements and climate changes is proposed. The volumes affected by these movements in different periods have been calculated and rates have been obtained. Estimates of denudation rates in the study area during the Quaternary and in the Holocene are also presented and compared with the former.

Scintigraphic demonstration of lactulose-induced accelerated proximal colon transit

Although lactulose, a widely used cathartic, is known to increase stool frequency, details of its site of action in the colon are obscure. In the present study a noninvasive scintigraphic technique was used to closely follow the movements of proximal colonic contents. Lactulose, 10–20 mL three times daily, significantly accelerated mean transit through the ascending colon from 12.9 ± 3.7 to 7.0 ± 2.5 hours (n = 11; P < 0.01). This was associated with the occurrence of mass movements, with six such events seen during lactulose treatment whereas only one was seen during the control study (P < 0.05). Lactulose also accelerated movement through the rest of the colon so that at 24 hours after dosing the geometric center of the isotope bolus was distal to that seen during the control study (6.6 ± 1.2 vs. 4.7 ± 1.3; n = 11, P < 0.001). This model of diarrhea in otherwise normal subjects was subsequently used to study the effects of viscous gels in diarrhea. The viscous and relatively poorly fermented gel ispaghula, 3.5 g three times daily, abolished mass movements and was associated with a small but significant increase in proximal colonic transit time, which increased from 6.1 ± 2.1 to 7.7 ± 1.5 hours (n = 8; P < 0.05). By contrast, the viscous but readily fermentable gelling agent guar gum, 5 g three times daily, further accelerated the cathartic effect of lactulose, with the mean transit time decreasing from 6.4 ± 2.3 to 4.7 ± 1.7 hours (n = 8; P < 0.05). The acceleration of proximal colonic transit by lactulose may be a useful model to study diarrhea and its modification by therapy.