Earthquake!

Today I experienced my second earthquake. Both of them occurred near my home town of Richmond, VA. Both times I thought it was a train at first.



This one was quite a bit stronger than the first, though. I was actually frightened by the intensity and the duration of this one. The house was noticably shaking and it lasted for nearly a minute.



My house is only about 75 miles from the epicenter. I saw reports on twitter of the quake being felt as far North as Toronto, as far West as Cincinnati, and as far South as Atlanta. I also saw reports of people in Manhattan reading about the quake on twitter moments before feeling it themselves.



It was a very surreal experience all around. Check out the USGS event page for more info on the earthquake.



Below is a video of the tremor as it passed vertical displacement detectors arrayed across the country.





From Phil Plait:




These are very sensitive instruments; note the scale on the lower graph showing the motion is only about 40 microns top-to-bottom! That’s less than the thickness of a human hair.




(via Bad Astronomy)