An earthquake currently rated 8.9 on the logarithmic 1-10 Richter scale has hit northeast of Tokyo near Honshu, Japan.
A people finder site is located at
http://japan.person-finder.appspot.com/
The site was tracking nearly 6,000 people by 8 a.m. EST, about the time the initial tsunami wave hit Hawaii.
The Richter scale, a coarse overall estimate of the power of a quake, is a base-10 logarithmic scale, which means the energy released by a quake rated 8 is about 10 times greater than that of a 7 and 100 times greater than a 6.
Earthquake ratings can be adjusted slightly after more measurements are made.
There are other ways to measure the force of a quake and the damage depends on the kind of ground and the sort of buildings (if any) in the area.
An 8.9 earthquake is a major event that, in this instance, also generated a tsunami.
Earthquakes usually also result in aftershocks that can be extremely damaging, especially because the local infrastructure is already weakened by the initial quake.
The initial quake occurred at
Friday, March 11, 2011 at 05:46:23 UTC
Friday, March 11, 2011 at 02:46:23 PM at epicenter
http://earthquake.usgs.gov/earthquakes/eqinthenews/2011/usc0001xgp/
This quake was located 15 miles under the surface and generated a tsunami warning for the Pacific Basin.
38.322A°N, 142.369A°E
Pacific Tsunami Warning Center
Scientists say earthquakes usually occur when various sections of the earth’s crust, particularly the tectonic plates that move around and have changed the position of the continents, move either sideways or push over or under another segment.
Of course, this explanation is based on the theory that the planet is billions of years old and keeps changing. In Norse mythology quakes were blamed on Loki. In Japanese mythology the giant catfish Namazu causes them.
This is a good time to recall that normally quiet areas such as the central U.S. can still experience major earthquakes such as the massive 1811-1812 New Madrid quake.
http://earthquake.usgs.gov/regional/ceus/
Find earthquake information geared to kids at
http://earthquake.usgs.gov/learn/kids/
