Conditions of formation of seismogenic landslides on Sakhalin Island

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.