Earthquake on the East Coast

Best quote of the day I saw so far on Facebook:  California is in such economic distress, now they've decided to outsource their earthquakes.

Anyway, the tremor today registered at a 5.8 magnitude with the epicenter about 38 miles northwest of Richmond, VA, in the town of Mineral.  An aftershock felt a couple hours ago registered at 4.2.  All signs so far point to this earthquake being unlike any other we have had in this part of the country, and there have not been many.  Unlike California, which is along a major fault system (the San Andreas Fault which separates two major tectonic plates), the Eastern US is generally in the middle of the North American Plate.  The closest major fault zones would be thousands of miles away in any direction

However, the underlying reason why we have faults in the first place is ultimately the reason why we had an earthquake here.  About 20-30 miles beneath the surface, the crust of the earth gives way to the mantle, a region of very hot matter, melted into a semifluid state.  This matter is heated by the extremely hot core.  Think about how weather works.  The whole reason we have weather is because of the rising and falling of heated matter.  In the case of weather, the matter is water.  In the case of plate tectonics, the matter is magma.  Now, we don't actually see this magma (there are not any volcanos around here), but the matter is rotating due to the rising and falling.  It's called convection.  Heat causes matter to rotate.  Over the course of millions of years, the direction of this rotation has been fairly constant, but who are we to guess if it stays that way.  There is no rhyme or reason to how matter moves within the mantle.  That direction can change without notice or warning.  As direction of the convection change, new faults can form. 

Somewhere along the east coast is a fault line, a relatively new fault line.  The crust has cracked into two pieces.  When the pieces get stuck together, they don't move, but they can only handle so much.  Consider a rubber band.  You can only stretch a rubber band so much until you supply enough force to it to cause it to snap.  This is exactly how an earthquake starts.  Once that energy is released, the quake stops, but it could release even more energy later in the form of aftershocks.  This earthquake registered 5.8, that's California territory folks.  That tells me that there was a lot of energy trapped at that focus point in Virginia.  Who knows where else there is energy building?

The East Coast is not known for earthquakes because we are not located on a major fault line.  All the earthquakes we have had in our history that I can remember have been very weak if even noticable.  We are not in any danger I feel for a Loma Prieta type event that can topple buildings.  The faults over here are not nearly large enough.  Nevertheless, geologists are going to study this one for a while to determine if they can figure out where this fault is, how long it is, and how what is the likelihood of another earthquake event in the near future.

In other natural disaster news, talk about a 1-2 punch.  We get an earthqake today...and a hurricane tomorrow...well, early next week.  Irene is churning out in the Atlantic, and while there is a very good chance this thing will stray off to the east, it bears close monitoring.  We are just now getting to the peak of hurricane season, and if you look at the National Hurricane Center's website, there are two areas of interest just off the west coast of Africa, the area of the Atlantic where big hurricanes like to form this time of year.