Conditions of landslides’s occurrence can be characterized.
It is different from the ones of collapse or the like.
In case of landslide, the lump of lands literally slides down the slope from the boundary as known as sliding surface
As I wrote last time, landslides occur when the sliding force pulling the soil mass in the direction of inclination exceeds the resistance of it.
And the main factor that creates this situation is the increase in water volume in the soil and groundwater volume due to rainfall and snowfall, and seismic ground motion often triggers it.
Then, where is a landslide likely to occur?
As you can see from the fact that rain is the main cause of landslides,
where rainwater easily penetrates are the alarming points.
One of a point you can see at a glance is slopes have muddy soil due to ground water. And the slope under the area spreaded out gradually upwards, where rainwater gathers in one place along the inclination.
The area that causes landslides is a narrow part of the mountain, but in order to find it before its occurrence, it is necessary to look over a wide range.