Earthquakes can destroy bridges, buildings, and even entire cities in just a few minutes. And in certain areas, earthquakes can trigger mudslides which slide down mountain slopes and can bury houses and other buildings. Fires can also happen when the water and gas lines break.

in easy words disaster happens-- but in terms of science the plates which makes earth crust, shakes and plates shakes which means density of plates decreases in the same way as when you put your hand in sand while rotating.. high mass when gets lower density gets into ground