1. What cause earthquaks to happen.

2. City Earthquake, September 19, 1985

3. Imperial Fault trace 1 kilometer south of County Highway S-80 (11.3 kilometers northwest of the southeast end of the fault). Echelon fissures (vertically oriented) trend N. 20-50 degrees W. The fault trace trends between N. 30-40 degrees W. Compressional features (dark horizontal bands) join the ends of the separate echelon fractures. The distance between the manmade berms (wide dark diagonal bands) is about 9.1 meters. The maximum width of the obviously deformed zone is about 0.6 meter. View is south.

4. Causes of earthquakes If seen broadly we can say that earthquakes are caused due to two major reasons. The first reason is the eruption of volcanoes, which are sudden, and as is known volcanoes are seat of inner disturbance and can effect the plates which is the second cause of earthquakes. Earthquakes are caused due to disturbance in the movement of plates, which again can be caused due to various reasons like under crust waves or cracks in the plates.

5. State Highway 86 bridge over the New River at site 32 west of Brawley. The abutment fill settled about 0.15 meter, and both ends of the bridge and riverbanks slumped about 0.1 meter toward the stream. Ground displacements caused the bridge decks to rotate about 0.3 degree counterclockwise in a horizontal plane, but did not seriously damage the structure.

6. Earthquakes usually occur in places where two plates meet, called faults. Earthquakes are mostly generated deep within the earth's crust, when the pressure between two plates is too great for them to be held in place. The underground rocks then snap, sending shock waves out in all directions. These are called seismic waves. The underground origin of an earthquake is called the focus. The point at which an earthquake originates on the surface is called the epicentre.faults seismic wavesfocusepicentre Earthquakes cannot be predicted although areas most at risk can be identified. The buildings in these areas then can be modified to withstand earthquake shocks. For example, buildings constructed near the San Andreas fault in San Fransisco, have to meet extremely strict building regulations. Storm-stained skies hover over the remains of a mobile home demolished by a passing tornado. Tornadoes kill about 60 people in the U.S. every year and cause billions of dollars of property damage. Damaged Mobile Home