The U.S. Geological Survey reports that, as of 2014, Alaska accounts for about half of all earthquakes registered in the United States. The USGS also indicates that many smaller magnitude earthquakes go unreported in the state. California has the second-most reported earthquakes among U.S. states.
Hawaii is the third-most prominent earthquake state and Nevada is fourth. However, the USGS site reports that these states are in a virtual dead heat on the number of quakes with a 5.0 or greater magnitude. Other states listed in the top 10 include Washington, Idaho, Wyoming, Montana, Utah and Oregon. The rankings include any quakes reported in any region within a state.Learn More
An earthquake occurs when the movement and breaking of rock masses happen on pre-existing faults. Once an earthquake hits, energy is created through seismic waves that travel through the Earth's crust.Full Answer >
The Chinese seismograph was an instrument developed in 132 A.D. by the Chinese philosopher Chang Hêng to detect earthquakes and determine the direction from which they came. It was a brass instrument decorated with eight dragons, each holding a copper ball. On the base were eight frogs, each with their mouth open, to catch the ball when it drops.Full Answer >
A reverse fault is a type of dip-slip fault that is formed by compression between two sections of rock. It differs from a normal fault, one that is formed by the stretching of the rock, in that the hanging wall is pushed over the footwall.Full Answer >
Approximately 1,500 earthquakes are recorded in Japan every year. The magnitude of each earthquake varies, and larger earthquakes between 4 and 7 on the Richter scale regularly occur. Records from the early 1990s indicate that there are 40 active volcanoes in Japan, which is 10 percent of the world total.Full Answer >