When the force of the moving blocks finally overcomes the friction of the jagged edges of the fault and it unsticks, all that stored up energy is released.
The energy radiates outward from the fault in all directions in the form of seismic waves like ripples on a pond. The seismic waves shake the earth as they move through it, and when the waves reach the earth’s surface, they shake the ground and anything on it, like our houses and us!
Earthquake Facts:
- The USGS Earthquake Info Center locates about 20,000 earthquakes each year (about 50 per day).
- On average, about 60 earthquakes per year are classified as significant, with up to 19 classified as major.
- A significant earthquake is one of magnitude 6.5 or higher or one of lesser magnitude that causes casualties or considerable damage.
- Major earthquakes have a magnitude larger than 7.0
- Large earthquakes that originate from the sea bed result in tsunamis, causing huge waves to travel 500 mph (800 km/h) or more toward coasts.
- There are 2 basic types of earthquakes. A strike-slip earthquake occurs when the rock on one side of a fault slides horizontally past the other. In a dip-slip earthquake, the fault is at an angle to the surface of the earth and the movement of the rock is up or down.
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