There are generally two types of hay bales. With quite different weights. The most common ones that people buy at feed stores or the farmer, and can be moved by one person, are the type you may have bucked into the barn for your uncle who had a farm when you were a teenager. They are around 3-4 feet long by 24x18 inches square.
How Earthquakes Happen. An aerial view of the San Andreas fault in the Carrizo Plain, Central California. An earthquake is the vibration, sometimes violent, of the Earth's surface that follows a release of energy in the Earth's crust. This energy can be generated by a sudden dislocation of segments of the crust, by a volcanic eruption, or event by manmade explosions.
Colocation in San Diego, Phoenix Earthquakes Are RARE in San Diego! California in general has a reputation for earthquakes, especially Los Angeles and San Francisco. This is because these cities sit on or near the San Andreas Fault which is the source of most seismic activity in California. As discussed more thoroughly below, however, the city of San Diego does not lie near the San Andres Fault and as a result has much lower seismic activity.