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The major research achievements of the Aerial Prediction of Earthquake and Rain Induced Flow Phenomena (APERITIF) project (IPL M101) are introduced in this paper in three parts. (1) Detection of landslide prone slope using airborne laser scanner, (2) Full-scale landslide flume experiments and an artificial rainfall-induced landslide experiment on a natural slope to understand the fluidization mechanism of rainfall induced landslides; (3) Landslide risk evaluation and hazard zoning in urban development areas. In part (3) as a comprehensive research of this project, application studies were conducted in two test sites in the Tama residential area near Tokyo. A series of field and laboratory investigations including laser scanner, geological drilling and ring shear tests were carried out and the results show that there is a risk of sliding surface liquefaction triggered by coming earthquakes for both sites. Developed in this project, a geotechnical computer simulation of landslide (Rapid/LS code) using parameters obtained from the undrained dynamic-loading ring shear tests makes urban landslide hazard zoning possible even at individual street level.

The Tien Shan is an intracontinental mountain system ∼1 500 km long and up to 500 km wide that formed between the Tarim Basin and the Kazakh Shield due to the India-Asian collision. It is shared by the five nations of Kyrgyzstan, Kazakhstan, Uzbekistan, Tajikistan, and China. As one of the highest and most seismotectonically active parts of the Central Asian Mountain Belt, it is extremely prone to large rock-slope failures. At least nine rock slope failures > 1 km in volume, two of which involved ∼10 km, have been identified in the Tien Shan. Thanks to an arid climate many of these formerly river-blocking rockslides and long-runout rock avalanches are well preserved, and both their morphology and internal structure may be readily studied in detail. Here we briefly describe the state-of-the-art and planned future international collaborations in research on rock-slope failures in the Tien Shan.

The village of Craco (Basilicata, Italy), is being affected by severe landslide phenomena mainly due to the geological and geomorphological setting of the area. The village has been interested by a progressive abandon of the population after the occurrence in the time of landslides and earthquakes that caused the disruption of large portions of the urban settlement. Several landslide typologies can be recognized in the area: rock-falls in the upper part of the hill, rotational and translational earth slides, earth-flows, rock lateral spreading. The main purpose of the paper is to reconstruct the evolution of the geological and morphological dynamics acting on the southern slope of Craco, where the largest landslides occurred in the past.

The analysis of deep landslide phenomena has been carried out with a multi-temporal geomorphological approach using analogical and digital photogrammetry on 4 different set of aerial photos (1954–1999). The analysis has stressed a progressive retrogression of the crown area in the upper portions of the hill that caused, in the recent past, the degradation or, in some cases, the complete disruption of part of the historical village, where most of cultural heritage was located.

The reconstruction of the landslide evolution acting in this area can be very useful as model to transfer in other areas characterized by similar geological and morphological setting that may result in large landslide phenomena. The suggestion of correct mitigation strategies may help to prevent environmental and, consequently, social degradation of the territory.

There are 327 monitored rock objects with more than 900 measuring sites on the territory of the Bohemian Switzerland NP and its nearest neighborhood, and the monitoring nets are ever growing. Therefore a high-tech, scientifically challenging Integrated System (IS) for effective, but nature-friendly management of rock fall risks on the Bohemian Switzerland NP territory has been under construction since 2002, there. Rapid processing and timely, on-line delivery of relevant, easy-to-understand information to an end-user through an information web portal and cellular phone emergency messages should be the highlights of IS. Other highlights are represented by the implementation of complex dynamical systems knowledge and methods to provide more realistic and mathematically more rigorous grasping of very complex dynamics of rock slope stability failure. Those methods also provide a basis for a qualitative step in implementation of computers for future highly automated run of data assessment, modeling and early warning modules of the system. Several successful case-histories have made those new tools very promising for the practical use. Nevertheless, there are some tasks still unfinished. Especially the one enabling to bridge the gap between science, civil protection and general public and by it to enhance effectiveness of utilization of delivered information by its end-users.

An experimental study on the liquefaction of clayey soils was conducted under ICL Project M124 “The influence of clay mineralogy and ground water chemistry on the mechanism of landslides” in order to better understand the mechanism of this phenomenon. The first section of this study deals with artificial mixtures of sand with different clays while the second is concerned with natural soils collected from landslides. The results from the first section are presented in this article. The investigation was conducted by means of a ring-shear apparatus and a scanning electron microscope (SEM). The results obtained for artificial mixtures enabled us to draw a line between liquefiable and non-liquefiable clayey soils and to define a criterion to estimate their liquefaction potential. In addition, the influence of clay content and clay mineralogy on the cyclic behavior of clayey soil was studied. It was found that an increase in clay content as well as the presence of bentonite clay raised the soil resistance to liquefaction. The analysis of microstructures of bentonite-sand mixtures along with the results from ring-shear tests revealed that the soil microstructure is the key factor in determining the dynamic properties of soil. For example, in the microstruc-tures of soils vulnerable to liquefaction, the clay matter was observed to form “clay bridges” between sand grains that were easily destroyed during cyclic loading. In the microstructures of soils resistant to liquefaction, the clay matter seemed to form a matrix that prevented sand grains from liquefaction. The influence of pore water chemistry on the liquefaction potential of artificial mixtures was also studied. It was found that the presence of ions in pore water changed the microstructure of clayey soil, thus making it more vulnerable to liquefaction.

Traditional approaches to prevent rainfall-induced landslides consist of such stabilization of unstable slopes as installation of retaining walls as well as ground anchors. Although having been useful in mitigation of large slope failures, those traditional measures are not very helpful in mitigation of small slope failures which are less significant in scale but numerous in numbers. It is proposed in the present text for people to install slope instability detectors which find precursors of an imminent slope failure and issue warnings so that people may be able to evacuate themselves prior to fatal slope failures. To achieve this goal, model tests as well as laboratory triaxial tests have been conducted in order to understand the behavior of soil prior to failure. Moreover, numerical analyses on ground water percolation and decrease of factor of safety in the course of rainfall were conducted on a sandy slope in order to support findings from model tests. As a whole, a small instrument is proposed for a use of people which can detect minor displacement and change of moisture content prior to failure in a slope and issue warning through internet.

The valley of Cusco occupies a depression derived of the Andean folding of continental and marine redbeds series and of volcanic rocks of the Upper Palaeozoic until the recent Quaternary. Due to lithological as well as structural factors, numerous landslides exist (around 170 according to our inventory; most of them in subactivity state) representing diverse levels of danger.

The landslides occur mainly in the Cretaceous evaporitic, calcareous and pelitics formations of the so-called Yuncaypata Group. In those formations the landslides respond mostly to the lithological genetic factor. The continental red beds of San Jeronimo Group (Lower and Middle Tertiary) show a smaller density than the Cretaceous formations and the landslides are conditioned by the structural factor (conform slopes). The volcanic rocks of the Permo-Triassic (Mitu Group) and Plio-Pleistocene (Rumicolca Formation) present a very low landslide occurrence, always conditioned by the structural genetic factor. At least two cases of deep Toppling becoming complex landslides have been identified in the San Jerónimo Group outcrops.

Using a new ring-shear apparatus with a transparent shear-box and video image analysis system, drained speed-controlled test was conducted on coarse-grained silica sands to study the shear-zone formation process in granular materials. Velocity distribution profiles of grains under shear at various stages in the ring shear test were measured through processing the video image by Particle Image Velocimetry (PIV) program. In the initial stage of shearing, comparatively major part of the sample in the upper shear box showed a velocity distribution due to deformation and dilatancy behavior. Thereafter, velocity distribution profile changed into slide-like mode and thereafter showed almost no change. This study was conducted as a part of the International Programme on Landslides M101 “Areal prediction of earthquake and rain induced rapid and long-traveling flow phenomena (APERITIF)” of the International Consortium on Landslides (ICL). These results will contribute to understanding the mechanism of shear-zone development in granular materials as a basic knowledge for disaster risk mitigation of rapid long runout landslides.

During the 2003 Sanriku-Minami earthquake, a flowslide was triggered on a gentle slope of about 13 degrees in Japan. The displaced landslide mass deposited on a horizontal rice paddy after traveled approximately 130 m. Field investigation revealed that the landslide was originated from a fill slope, where a gully was buried for cultivation some decades ago, and shallow ground water exists. To investigate the trigger and movement mechanism of this landslide, a series of seismic simulating tests was performed on the sample taken from the source area, by using a newly developed ring shear apparatus. The seismic loadings were synthesized using the seismic records at the same earthquake. The undrained and partially drained tests revealed that shear failure and post-failure landsliding could be resulted due to the seismic loading, given the existence of saturated soil layer above the shear zone in certain thickness.

The Hime River Basin is located in the northern part of Central Japan and is known as one of the areas where both erosional potential and sediment yield are extremely high in Japan. Landslides and debris flows triggered mainly by heavy rainfalls have frequently occurred in the basin. We have estimated the chemical weathering rates for nineteen watersheds in the Shirouma-Oike Volcano located in the western part of the basin. These rates have been simply estimated by the mass balance equation between solute fluxes of stream waters from each watershed and solute loss comparing fresh and weathered volcanic rocks and were calculated to be ranging from 0.15 to 3.24 mmyr. A watershed showing the highest rate of chemical weathering and solute flux corresponded to the area where the large-scale landslide occurred in 1911 and debris flows and landslides have continually occurred until now. Unstable sediments yielded by chemical weathering are thought to be an important factor of sediment disaster occurrences in the research area. Solute fluxes of each stream could be useful for susceptibility mappings of landslides and debris flows in each watershed.

A cause of the high chemical weathering rate is the leaching of soluble elements from fresh bedrocks with sulfuric acid produced by the oxidation of pyrite in altered rocks by previous hydrothermal activities. Stream waters from the altered zones are characterized by high SO4/Cl ratio. Such a simple hydrochemical signature could also be useful for detection of hydrothermally altered zones covered with vegetation and thick soil layers.