EARTHQUAKE!

A very unusual earthquake struck Mineral, Virginia this afternoon at about 1:51pm EDT. I was sitting at my desk at work when it struck, and felt it here in Raleigh, North Carolina. At first we didn’t know what it was, or if it was related to nearby construction in the area, but most at the office felt it. Intense! This will be my first earthquake. Here is a link to the quake at the USGS website.

It was more like a small tremor here in Raleigh. As exciting as it sounds to witness such an unusual force of nature, what’s important is that the damages were few and far between. It was felt from South Carolina to Maine, but the extent of damages occurred at the Washington National Cathedral. In fact, some very funny internet meme’s are already circulating about the quake. Important to note here that earthquakes less than a 6.0 magnitude rarely cause damages to roads, buildings, or bridges, but if there’s any doubt, structures should be evaluated.

I worked on a few earthquake simulations at the Constructed Facilities Lab at NC State. We had a shake table to use to simulate the effects of an earthquake, similar to this one. You may hear peers or even members of the media refer to the “Richter Scale.” This is wrong! The Richter Scale was abandoned years ago because of the upper limit on it’s order of magnitude and it’s unreliability at around 600km away. MMS, a similar logarithmic scale, replaced Richter. It is similarly based on orders of magnitude, i.e. a 6.0 earthquake is 10-times as strong as a 5.0 earthquake, a 7.0 10-times as strong as a 6.0, and so on, but without the inherent problems of the older method.

Recent events such as the earthquakes in Chili, Haiti, and Japan have brought Earthquake Engineering back into the spotlight. This is a very important field and one that deserves more research funding than it receives. Very rare to have an earthquake of this magnitude in this area of the United States. If you felt it, congratulations. Now get back inside and go back to work.

Still quiet here.sas

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