Conditions of formation of seismogenic landslides on Sakhalin Island

Nikolay Kazakov,Sergey Kudryavtsev,S Kudryavtsev,C Yoo,A Zhussupbekov

doi:10.1051/matecconf/201926504012

Abstract

There is no direct connection between landslide and seismic processes. The increase in humidity of rocks during a long period of high humidity (6-7 years) with a large amount of precipitation causes an increase in the humidity of rocks in landslides to the upper limits of plasticity (or fluidity) of soils, which leads to a decrease in their stability and activation of landslide processes. The consequence of reducing the stability of landslide arrays is to increase the probability of activation of landslide processes under seismic effects on landslide arrays. Strong hydration of rocks during the previous cycle of high humidity is maintained for at least 2 years. Therefore, in the first 2 years after the beginning of the low humidity cycle, the conditions for the activation of landslide processes in an earthquake remain. Similarly, in the first 2 years after the beginning of the high-water cycle, the rocks of landslide massifs are still not sufficiently moistened, and the probability of landslides formation in earthquakes is low. Long-term forecast of seismogenic landslides can be made as a forecast of periods of increased risk of landslides based on the account of the cycles of moisture (increase in precipitation) and physical and mechanical characteristics of rocks of landslides.

Highlights

Sakhalin Island is one of those regions of Russia where landslide hazard for the population are very high
The increased moisture of rocks during the long-term period of increased moisture with a large amount of precipitation causes an increase in the humidity of rocks in the landslide massifs to the upper limits of plasticity of soils, which leads to a decrease in their stability and activation of landslide processes
The consequence of reducing the stability of landslide arrays is to increase the probability of activation of landslide processes under seismic effects on landslide arrays

Summary

Introduction

Sakhalin Island is one of those regions of Russia where landslide hazard for the population are very high. The high intensity of landslide processes is due to the relief of Sakhalin Island (young mountains with steep slopes), the geological structure of the territory (unstable rocks – siltstones, sandstone and mudstones – are destroyed and involved in landslides) and a large amount of precipitation. The relief of Sakhalin Island forces to place settlements, economic and industrial facilities, highways and other infrastructure in landslide-prone areas: in the bottoms of narrow mountain valleys and on the surface of low sea terraces under the slopes of high abrasion-denudation terraces. The territory of the Sakhalin Island earthquake. The cases of landslides during earthquakes was describes, but the issue of the conditions of formation of seismogenic landslides is not investigated.

Landslides on Sakhalin Island

Landslide process Mode

Categories of landslide danger

Damage from landslide processes on Sakhalin Island

Forecast of seismic activation of landslide processes on Sakhalin Island

Discussion and conclusions