Earthquakes trigger soil liquefaction in some places. The tremors cause the rock particles in the soil to lose their cohesion, meaning that the pore space is expanded, water can seep in and subsoil that was previously solid loses its strength. This phenomenon can occur where the soil is very waterlogged and not very compact. Therefore, sediments and loose rocks, such as those found in valleys, are particularly affected. Such soil liquefaction was, for example, observed in Switzerland after the magnitude-5.8 earthquake in Sierre in 1946.