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.
The Great San Francisco Earthquake of 1906. The great San Francisco earthquake struck on Wednesday, April 18, 1906 at 5:12 am, with the offshore epicenter about 3 km (2 mi) south of the city. It ruptured 477 km (296 mi) along the San Andreas Fault. People felt shaking from Oregon in the Pacific Northwest to Los Angeles and from the inland to central Nevada.