About 67 destructive or powerful earthquakes occurred in 1985. The strongest earthquake occurred on September 19, in Mexico City. The earthquake reached a magnitude 7.9, according to the United States Geological Survey. The Mexico earthquake caused between 3 and 4 billion U.S. dollars of damage, and was felt by almost 20 million people; at least 9,500 people were killed, and about 30,000 were injured.