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Loi D.H.,Institute of Transport Science and Technology | Quang L.H.,Institute of Transport Science and Technology | Sassa K.,International Consortium on Landslides | Thanh N.K.,Institute of Transport Science and Technology | And 4 more authors.
Landslides | Year: 2017

From 26–28 July, heavy rainfall occurred in Quang Ninh province causing flooding, debris flows and landslides. It was the largest disaster triggered by torrential rainfall in Vietnam in 2015. The immediate economic loss in Quang Ninh is estimated to be about VND 2000 billion (US$92 million). Seventeen people were reported dead, 1,459 households were evacuated and at least 30 houses were destroyed. Eight of the victims died when a landslide buried three houses at Cao Thang ward, Ha Long City. We undertook field investigation and ring-shear simulations to study the initiation mechanism and behaviour of the landslide. The rainfall-induced pore-water pressures were estimated using the Slope-Infiltration-Distributed Equilibrium (SLIDE) model developed by Sassa et al. (2010) and Liao et al. (2010, 2012). The ring-shear apparatus (ICL-1) was used to simulate the soil failure, formation of sliding surface and steady-state motion of the landslide. Landslide dynamic parameters obtained and estimated from ring-shear tests were used in the integrated simulation model LS-RAPID to simulate landslide motion. The results demonstrate that the LS-RAPID model predicts a similar hazard area to that observed in the field investigation. In addition, the time of landslide occurrence estimated from the rainfall record and the LS-RAPID simulation is close to the time of occurrence reported by local inhabitants. © 2017 Springer-Verlag Berlin Heidelberg

Sassa K.,International Consortium on Landslides | Tsuchiya S.,University of Shizuoka | Fukuoka H.,Niigata University | Mikos M.,University of Ljubljana | Doan L.,Kyoto University
Landslides | Year: 2015

The international journal Landslides: Journal of International Consortium on Landslides was established in April 2004. The aims of Landslides are to promote landslide science, technology, and capacity building, and to strengthen global cooperation for landslide risk reduction within the United Nations International Strategy for Disaster Risk Reduction (ISDR). The achievements of the first 5 years from the beginning of 2004 (Vol. 1, No. 1) to the mid-2009 (Vol. 6, No. 2) were reviewed in 2009 (Landslides 6:275–286, 2009). This article presents the review for the second 5-year period from mid-2009 (Vol. 6, No. 3) to the end of 2013 (Vol. 10, No. 6), focusing on the journal’s significance and its impact. We include an analysis of the classifications of articles in Landslides. © 2015, Springer-Verlag Berlin Heidelberg.

Sassa K.,Kyoto University | Canuti P.,International Consortium on Landslides | Margottini C.,European Commission - Joint Research Center Ispra | Yin Y.,China Institute of Geo Environment Monitoring
Landslides | Year: 2012

The Second World Landslide Forum was held at the headquarters of Food and Agriculture Organization of the United Nations on 3-9 October 2011 in Rome, Italy. The Third World Landslide Forum (WLF3) is to be held at the China National Convention Center in Beijing, China from 2 to 6 June 2014. This article first outlines the aims and background of the World Landslide Forums, reports on the Second World Landslide Forum in Rome, and then announces the plans for the Third World Landslide Forum in Beijing. Finally, it calls for contributions for the organization of WLF3 and participation in the International Consortium on Landslides (ICL) and the International Programme on Landslides. © 2012 Springer-Verlag.

Apip,Kyoto University | Takara K.,Kyoto University | Yamashiki Y.,Kyoto University | Sassa K.,International Consortium on Landslides | And 2 more authors.
Landslides | Year: 2010

This paper describes the potential applicability of a hydrological-geotechnical modeling system using satellite-based rainfall estimates for a shallow landslide prediction system. The physically based distributed model has been developed by integrating a grid-based distributed kinematic wave rainfall-runoff model with an infinite slope stability approach. The model was forced by the satellite-based near real-time half-hourly CMORPH global rainfall product prepared by NOAA-CPC. The method combines the following two model outputs necessary for identifying where and when shallow landslides may potentially occur in the catchment: (1) the time-invariant spatial distribution of areas susceptible to slope instability map, for which the river catchment is divided into stability classes according to the critical relative soil saturation; this output is designed to portray the effect of quasi-static land surface variables and soil strength properties on slope instability and (2) a produced map linked with spatiotemporally varying hydrologic properties to provide a time-varying estimate of susceptibility to slope movement in response to rainfall. The proposed hydrological model predicts the dynamic of soil saturation in each grid element. The stored water in each grid element is then used for updating the relative soil saturation and analyzing the slope stability. A grid of slope is defined to be unstable when the relative soil saturation becomes higher than the critical level and is the basis for issuing a shallow landslide warning. The method was applied to past landslides in the upper Citarum River catchment (2,310 km2), Indonesia; the resulting time-invariant landslide susceptibility map shows good agreement with the spatial patterns of documented historical landslides (1985-2008). Application of the model to two recent shallow landslides shows that the model can successfully predict the effect of rainfall movement and intensity on the spatiotemporal dynamic of hydrological variables that trigger shallow landslides. Several hours before the landslides, the model predicted unstable conditions in some grids over and near the grids at which the actual shallow landslides occurred. Overall, the results demonstrate the potential applicability of the modeling system for shallow landslide disaster predictions and warnings. © 2010 Springer-Verlag.

Sassa K.,International Consortium on Landslides | Dang K.,International Consortium on Landslides | Dang K.,Vietnam National University, Hanoi | Yanagisawa H.,Tohoku Gakuin University | He B.,CAS Nanjing Institute of Geography and Limnology
Landslides | Year: 2016

By combining landslide dynamics research and tsunami research, we present an integrated series of numerical models quantitatively simulating the complete evolution of a landslide-induced tsunami. The integrated model simulating the landslide initiation and motion uses measured landslide dynamic parameters from a high-stress undrained dynamic-loading ring shear apparatus. It provides the numerical data of a landslide mass entering and moving under water to the tsunami simulation model as the trigger of tsunami. The series of landslide and tsunami simulation models were applied to the 1792 Unzen-Mayuyama megaslide and the ensuing tsunami disaster, which is the largest landslide disaster, the largest volcanic disaster, and the largest landslide-induced tsunami disaster to have occurred in Japan. Both the 1792 megaslide and the tsunami portions of the disaster are well documented, making this an excellent test of the reliability and precision of the new simulation model. The simulated tsunami heights at the coasts well match the historical tsunami heights recorded by “Tsunami-Dome-Ishi” (a stone showing the tsunami reaching point) and memorial stone pillars. © 2016 Springer-Verlag Berlin Heidelberg

Sassa K.,International Consortium on Landslides | He B.,Kyoto University | Miyagi T.,Tohoku Gakuin University | Strasser M.,ETH Zurich | And 6 more authors.
Landslides | Year: 2012

The distinctive bathymetric feature exists in the Suruga Bay, Japan. It has been called as Senoumi (Stone flower sea) from old times. Senoumi is a 30 km wide and 20 km long concave feature. Its origin has not been explained yet; however, the feature might be a combined consequence of intensive tectonic activity in the plate border, landslides, and a submarine flow coming from the Oi River. If the Senoumi was caused by a landslide, the latter would be larger than any on-land landslide in Japan. The downshelf "exit" from this feature is much narrower than its central part. This is not usual shape of landslides, but it is similar to the liquefied landslides such as those in quick clays which mobilize great strength reduction after failure. To study Senoumi as a landslide, the shear behaviors of the following three soil samples were investigated by the cyclic and seismic undrained stress control ring shear tests. One sample is volcanic ash taken from the base of landslide deposits (mass transport deposits), from 130 to 190 m deep layer below the submarine floor which was drilled and cored by the Integrated Ocean Drilling Program Expedition 333. Another two samples are the Neogene silty-sand and silt taken from the Omaezaki hill adjacent to the Senoumi, because the shear zone might have been formed in Neogene layers extending from on-land to the continental shelf. The largest strength reduction from peak to steady-state shear resistance in the undrained cyclic loading test was found in volcanic ash. The strength reduction in Neogene silty-sand was smaller than volcanic ash, while the Neogene silt mobilized the least post-failure strength reduction. An integrated model simulating the initiation and motion of earthquake-induced rapid landslides (landslide simulation (LS)-RAPID, Sassa et al. Landslides 7-3:219-236, 2010) was applied to this study. The steady-state shear resistance and other geotechnical parameters measured by the undrained ring shear tests and the greatest strong motion record in the 2011 off-the-Pacific Coast of Tohoku earthquake (Mw 9. 0), also known as "2011 Tohoku Earthquake" at the observation point MYG004 (2,933 gal) were input to this model. As the result, it was found that landslides would be triggered by 0. 30-1. 0 times of MYG004 in volcanic ash, 0. 4-1. 0 times of MYG004 in Neogene silty-sand and Neogene silt, though the depth and area of triggered landslides were different in soils and intensity of shaking. Feature, created by LS-RAPID using the parameters of volcanic ash, was most similar to the Senoumi in depth and extent. The result obtained from this study includes a hypothesis to be proved, but presents the strong need to investigate the risk of the large-scale submarine landslides which could enhance tsunami wave and possibly enlarge the submarine landslide retrogressively into the adjacent coastal plain by the upcoming mega earthquake in the Nankai Trough. © 2012 Springer-Verlag.

Sassa K.,International Consortium on Landslides | Dang K.,International Consortium on Landslides | Dang K.,Kyoto University | He B.,CAS Nanjing Institute of Geography and Limnology | And 3 more authors.
Landslides | Year: 2014

Sassa and others in the Disaster Prevention Research Institute (DPRI), Kyoto University, developed a series of undrained ring-shear apparatus to physically simulate landslide initiation and motion, from DPRI-3 (Sassa 1992) to DPRI-7 (Sassa et al., Landslides 1(1):7–19, 2004). The maximum undrained capacities in the DPRI series ranged from 300 to 650 kPa. Sassa and others in the International Consortium on Landslides (ICL) have developed a new series of undrained ring-shear apparatus (ICL-1and ICL-2) for two projects of the International Programme on Landslides (IPL-161 and IPL-175). Both projects are supported by the Science and Technology Research Partnership for Sustainable Development Program (SATREPS) of Japan. ICL-1 was developed to create a compact and transportable apparatus for practical use in Croatia; one set was donated to Croatia in 2012. ICL-2 was developed in 2012–2013 to simulate the initiation and motion of megaslides of more than 100 m in thickness. The successful undrained capacity of ICL-2 is 3 MPa. This apparatus was applied to simulate possible conditions for the initiation and motion of the 1792 Unzen–Mayuyama megaslide (volume, 3.4 × 108 m3; maximum depth, 400 m) triggered by an earthquake. The megaslide and resulting tsunami killed about 15,000 people. The Unzen Restoration Office of the Ministry of Land, Infrastructure and Transport (MLIT) of Japan systematically collected various papers and reports and published two summary leaflets: one in English in 2002 and an extended version in Japanese in 2003. Samples were taken from the source area (for initiation) and the moving area (for motion). The hazard area was estimated by the integrated landslide simulation model LS-RAPID, using parameters obtained with the ICL-2 undrained ring-shear apparatus. The estimated hazard area agrees reasonably with the landslide moving area reported in the Ministry leaflets. © 2014, Springer-Verlag Berlin Heidelberg.

Liao Z.,University of Oklahoma | Hong Y.,University of Oklahoma | Hong Y.,Center for Natural Hazard and Disaster Research | Wang J.,University of Oklahoma | And 5 more authors.
Landslides | Year: 2010

An early warning system has been developed to predict rainfall-induced shallow landslides over Java Island, Indonesia. The prototyped early warning system integrates three major components: (1) a susceptibility mapping and hotspot identification component based on a land surface geospatial database (topographical information, maps of soil properties, and local landslide inventory, etc.); (2) a satellite-based precipitation monitoring system (http://trmm. gsfc.nasa.gov) and a precipitation forecasting model (i. e., Weather Research Forecast); and (3) a physically based, rainfall-induced landslide prediction model SLIDE. The system utilizes the modified physical model to calculate a factor of safety that accounts for the contribution of rainfall infiltration and partial saturation to the shear strength of the soil in topographically complex terrains. In use, the land-surface "where" information will be integrated with the "when" rainfall triggers by the landslide prediction model to predict potential slope failures as a function of time and location. In this system, geomorphologic data are primarily based on 30-m Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) data, digital elevation model (DEM), and 1-km soil maps. Precipitation forcing comes from both satellite-based, real-time National Aeronautics and Space Administration (NASA) Tropical Rainfall Measuring Mission (TRMM), and Weather Research Forecasting (WRF) model forecasts. The system's prediction performance has been evaluated using a local landslide inventory, and results show that the system successfully predicted landslides in correspondence to the time of occurrence of the real landslide events. Integration of spatially distributed remote sensing precipitation products and in-situ datasets in this prototype system enables us to further develop a regional, early warning tool in the future for predicting rainfall-induced landslides in Indonesia. © 2010 Springer-Verlag.

Sassa K.,International Consortium on Landslides | Yin Y.,International Consortium on Landslides | Canuti P.,International Consortium on Landslides
Landslides | Year: 2015

The Third World Landslide Forum was held on 2–6 June 2014 at the China National Convention Center, Beijing, China. This article outlines the background and the objectives of the World Landslide Forums and reports on the organized sessions and published books for the Third World Landslide Forum. During this triennial event of ICL, World Centres of Excellence on Landslide Risk Reduction and IPL Awards for Success, Varnes Medal, Best paper awards, and others were conferred. Through the examination in the high-level panel discussion on the first day and the roundtable discussion on the final day, 2014 Beijing Declaration “Landslide Risk Mitigation: Toward a Safer Geo-environment” was adopted. It is a document calling to join the planned Sendai partnerships 2015–2024 as a contribution to post-2015 Framework for Disaster Risk Reduction. © 2015, Springer-Verlag Berlin Heidelberg.

Sassa K.,International Consortium on Landslides | Nagai O.,International Consortium on Landslides | Solidum R.,Institute of Volcanology and Seismology | Yamazaki Y.,GODAI Development Corporation | Ohta H.,Ohta Geo Research Co.
Landslides | Year: 2010

A gigantic rapid landslide claiming over 1,000 fatalities was triggered by rainfalls and a small nearby earthquake in the Leyte Island, Philippines in 2006. The disaster presented the necessity of a new modeling technology for disaster risk preparedness which simulates initiation and motion. This paper presents a new computer simulation integrating the initiation process triggered by rainfalls and/or earthquakes and the development process to a rapid motion due to strength reduction and the entrainment of deposits in the runout path. This simulation model LS-RAPID was developed from the geotechnical model for the motion of landslides (Sassa 1988) and its improved simulation model (Sassa et al. 2004b) and new knowledge obtained from a new dynamic loading ring shear apparatus (Sassa et al. 2004a). The examination of performance of each process in a simple imaginary slope addressed that the simulation model well simulated the process of progressive failure, and development to a rapid landslide. The initiation process was compared to conventional limit equilibrium stability analyses by changing pore pressure ratio. The simulation model started to move in a smaller pore pressure ratio than the limit equilibrium stability analyses because of progressive failure. However, when a larger shear deformation is set as the threshold for the start of strength reduction, the onset of landslide motion by the simulation agrees with the cases where the factor of safety estimated by the limit equilibrium stability analyses equals to a unity. The field investigation and the undrained dynamic loading ring shear tests on the 2006 Leyte landslide suggested that this landslide was triggered by the combined effect of pore water pressure due to rains and a very small earthquake. The application of this simulation model could well reproduce the initiation and the rapid long runout motion of the Leyte landslide. © 2010 Springer-Verlag.

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