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.
Where do most earthquakes occur? Earthquakes occur when the Earth's plates move and rub against or bump into each other. Quakes occur most frequently along the edges of plates, but they are also common along faults, which can be far from the edge of a plate. Faults are cracks where smaller sections of the plate move against each other.