Earthquake Trumps Hurricane
With all due respect to Hurricane Irene, Tuesday’s 5.8 magnitude earthquake in Central Virginia is the big ‘SCIENCE’ story in the USA for a day at least.
Now I know Richter Scale numbers are hard to translate. After all, how can a 5.8 quake be 10 times stronger than a 4.8 and 100 times more potent than a 3.8 and yes 1,000 times more powerful than a 2.8? It takes a mathematician to describe that logarithmic measure.
Suffice it to say, that the Harts, Lincoln County WV 2.3 tremor of September 14, 2010 was some 5,000 times tamer than Monday’s true earthquake.
Dr. Bill Niemann, Marshall Geology chair, tells me the shallow nature of the Mineral, Virginia quake played a big role in our region feeling effects. The quake occurred at a depth of only 3.5 to 4 miles underground. That is shallow by earthquake standards. That means more energy can be pushed up to the surface of the earth for longer distances.
Now since the subsurface is made up of hard bedrock, Dr. Niemann says more energy will be “conducted” along the path of motion of the quake.
That’s a fancy way to say this quake had more bang for its buck when it came to energy transfer farther away from the epicenter to distant areas.
So suffice it to say this 5.8 quake, the strongest in Virginia since the late 1800s, was no wimp.
For comparison, here are the magnitudes of some recent notorious earthquakes.
Haiti, 2010, 6.0
Seattle, 1998, 6.8
LA, January 1994, 6.7
San Fran-Oakland World Series 1989, 7.1
In effect, the Mineral quake was roughly as strong as the Seattle quake of 1998, but 10 times less strong (weaker) than these notorious earthquakes.