A Landslide is a type of mass movement that occurs when a thin block of soil, rock, and debris separates from the underlying bedrock.
Actually, this thin block of soil and rocks were held by Tree's roots so it do not separated from the bedrock. Now days, more and more trees were cutted down for modern development, and more landslides happen because of this.
Mostly its the tectonic plates that shift under us that causes earthquakes, how they shift changes the damage the earthquake can cause so tectonic plates unless u want the mythological one which is some earth god scratching his back
Answer:
A cannot be accurately measured