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XXXXPeople use The Modified Mercalli Scale to measure the intensity of earthquakes. The spread of the scale is from 1 to 12, with 1 being the lowest and 12 being the highest.

XXXXEarthquakes have been studied since the 16th century when earthquakes were first recorded. During that time the cause of earthquakes were a mystery. Sometimes people thought giant snakes lived underneath the earth's surface. The first description of an earthquake was in 1177 B.C in China. China also had several large earthquakes occur in the following thousand years . Europe recorded that it had earthquakes as early as 580 B.C. Effects of earthquakes were written in the 17th century though most were exaggerated. However, the earliest earthquake in the Americas was in the 14th century. Earthquakes can stretch. For example, one earthquake in New Madrid, Missouri, stretched all the way to Denver, Colorado, on the west and Boston, Massachusetts, to the east. An earthquake in Alaska could be felt 500,000 square miles away.

XXXXThe San Fransisco earthquake in 1906 destroyed most of the city. After the disaster was over about 250,000 people were left homeless. Everyday earthquakes occur in areas as small as the land mass of England. Most earthquakes, however, cannot be felt by humans.

XXXXStrict building codes have been implemented worldwide to strengthen buildings so that they can withstand moderate earthquakes.