Аssessment of a landslide hazard taking into account seismic impact

Abstract

Landslides represent a major threat to human life, constructed facilities, infrastructure and natural en-vironment in many regions of the world. During the decade 2000-2009, natural disasters caused nearly one million facilities, affecting nearly 2.5 billion people across the globe. The landslide frequency of about 20 major events per year in Europe is the highest compared to floods, earthquakes and cyclones. All 50 States and the U.S. territories are subjected to landslides and other ground-failure problems; 36 States have changed (from moderate to highly) the severe landslide hazards. Landslides in the USA constitute a serious hazard. They cause the substantial human and financial losses, estimated as 25…50 deaths annually and to cost approximately $ 1 billion to $ 3 billion per year.
Activation of seismic activity in Vrancea area, the Black Sea region and in the whole world has led to increase level of seismic hazard in Ukraine and in the finally growth relevant provoke factors of landslide movement. Whole Ukraine, not only as earlier considered Carpathian and Crimean regions, is now an area with high potential risk of future huge earthquakes. "... Іn areas with reduced characteristics of soil (frequent flooding, landslides, etc.) can be observed 7–8-magnitude effects", – said the deputy director of the Institute of Geophysics of the National Academy of Science of Ukraine O. Kendzera. Before the Japanese earthquake (11.03.2011) considered in the world that at 9-magnitude earthquake acceleration of ground can be maximum of 0,4 g. "But the Japanese catastrophy showed whole 2,7 g. This led to much more damage than expected. This means that now is the time when we must to correct all parameters of earthquakes," – says S. Ohasyan, the director of the Armenian Institute of Geophysics and Engineering Seismology. And О. Kendzera added: "... we must to correct initial data, that designers will use in the projects of buildings and construction".
In the early stages of the design of anti-slip structures for operational approximate calculations of the slope and shear pressure coefficient, a program is required that has the following properties: ease of use; graphical, human-oriented interface; is based on tried and tested mathematical methods; endowed with a pleasant form of presentation of the results of calculations (graphical and tabular forms); speed of calculations, etc. LANDSLIDE meets these requirements. An example of taking into account seismic factors when calculating slopes according to the second group of boundary states is considering. A typical calculation using the LANDSLIDE program is given. Тhe slope stability coefficients was calculated using the LANDSLIP program by Maslow-Berer and Shakhutnyants methods. By using the limit equilibrium theory, the mechanism of “unloading the accumulated tension” in the slope massive during an earthquake is described.