Earthquakes can cause great damage. Over the past few years there have been a total of 56-80 earthquakes. It has endangered many residents and will continue to. Earthquakes are very deadly and many peoplei in San Francisco may agree. Between the fire and the earthquake no one will ever be sure which one caused the most damage. On April 18, 1906 at approximately 5:12 am a fire started in San Fransisco. A rupture along the Tomales-Portola which is also known as the San Andreas fault line caused the earthquake The city of San Francisco was located along the San Andreas Fault line. The San Andreas Fault extends 810 miles through California. About 270 miles of ground surface was ruptured in Northern California. The epicenter was located near San Francisco.The Great San Francisco Earthquake caused the ground to shift at about 4 to 5 feet per second, and the rupture traveled at about 5,900 miles per hour. The magnitude of the earthquake was estimated to be 7.8. on the Richter scale. Earthquakes happen along fault lines, the lines where tectonic plates meet. Tectonic plates are the huge rocky plates that make up the surface of the earth. Tectonic plates can move apart or collide with each becaue of pressure. This powerful movement tears apart the surface of the Earth releasing energy like shock waves which cause earthquakes. The two tectonic plates that interacted to cause the earthquake were the Pacific Plate and the North American Plate on the boundary line that is
