23 August 2011
The view from two seismographs near the epicenter. The quake has been rated at 5.9 and was very shallow at 6 km. It was felt in Montgomery, Alabama and in Fredericton, New Brunswick. Will add more data on this page soon.
There are two types of earthquake waves. Body waves and surface waves. Body waves travel in the Earth and are either P waves or S waves. P waves are push-pull waves and S waves are vertical waves. On the surface another type of wave called a Rayleigh wave is similar to the action of an S wave, and it causes most of the damage. Michigan Tech Univ. has a great page showing these waves here.
Below is an animation of a Rayleigh wave from Mich. Tech. Notice how objects move in a circle as the wave passes. If you felt the quake today on the East Coast, you moved in a circle as well. The bigger the circle, the more you felt it!
Callan Bentlley at Mountain Beltway has a lot more about the quake today and being a Geologist it is right up his alley!