Each year there are on average about 100 earthquakes of magnitude 6 or greater, and 20 earthquakes of magnitude 7 or greater. This comes to about 1 potentially damaging earthquake every 3 days, and 1 severe earthquake every 3 weeks. Government Hill School in Anchorage, Alaska, collapsed due to soil failure during the quake of 1964. The Main Earthquake Hazards Ground shaking results directly from an earthquake. It is the most common danger and can cause many other secondary effects which are listed below.
Objects can fall from shelves, ceilings, building, etc.
Fires are caused by disruption of electric, gas, or oil lines which can rupture from the ground shaking. Due to the ground shaking, avalanches cause snow to behave like a liquid and slide down a mountain. Avalanches can bury mountain side homes and destroy forests. Land slides involve dry soil, and mud slides are caused by a water and soil mixture. When the dam breaks the water escapes, flooding the surrounding area.