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.
Earthquakes occur most frequently around the edges of tectonic plates, especially where two plates are either colliding or sliding past one another. The most active earthquake zones in the world are in areas around the edges of the Pacific oceanic plate, such as California, Indonesia, Japan and New Zealand.