VT earthquake experts answer questions in Louisa County

LOUISA, VA (WWBT) - "Everywhere we go, we'll say well, so what happened at your house?" said Mary Frances Hoh, a Louisa County resident.

They're the rumbles everyone in Louisa County still talks about and the reason many in Louisa County say they're still living on edge. After more than 30 aftershocks, they're worried about what might come next.

Earthquake experts were in Louisa Tuesday evening, answering questions about aftershocks and the possibility of another earthquake. The Virginia Tech professors travel all over the world surveying earthquake damage and they got a first-hand look at the damage in Louisa.

"We wanted to hear what he had to say about the chances of another earthquake," said Joan Leckie.

"I would think that the earth would actually open up and swallow people and that didn't happen, but all that shaking was pretty scary," added Hoh, who remembers the scene from many childhood movies.

Randy Holliday teaches Earth Science for high schoolers in Louisa County. He has some background with geology, but is still eager to hear from the experts.

"Some reassurance that we can all kind of stop holding our breath and wondering when the next one's going to happen," he said.

Earthquake experts at Virginia Tech say the number and size of the aftershocks is promising.

"The aftershocks seem to be dying down so we don't see a rise in aftershocks," said Russell Green, a Virginia Tech earthquake expert. "That gives you some comfort that it's not triggering another earthquake, that the stress didn't move from one fault to another fault and we'll have another earthquake occur."

But, Russell adds, that doesn't mean there won't be another one at some point,"Yes, it will happen again. It's just a matter of when it's going to occur. Is it going to be 100 years, 200 years, 10 years?"

Experts say they can't actually predict when an earthquake will hit. It's just not scientifically possible,  so what they do is assess the damage after an earthquake and then work to make affected buildings stronger so the damage won't happen again.

There are many things you can do to reduce the structural vulnerability of your home.  Consider the process like "baby proofing" your home. Make sure your contents are secured in your cabinets. Pay special attention to your water heater. Also, make sure your gas line has flexible connections. Often, after earthquakes it's important to turn off your gas line.

If you had problems with your chimney, talk to your contractor. You can tie it to the roof with steel bracing and tie it to the rafters. If you get a new chimney, consider using concrete backup inside the chimney and tie it to the roof and floor joints.

You can also use steel bolts to tie your house to the foundation.

Another hot topic among participants was nuclear reactors near the epicenter. The experts from Virginia Tech went to part of the scene. It wasn't the most sensitive part of the reactor, but the area around it.

They say the part of the reactor they visited seemed structurally sound. They also added that the "safe area" they visited was built to a lesser standard than the more sensitive area that they didn't visit. Deductively, he believes that the sensitive area is probably safe too.

Russell tells us that nuclear reactors are held to the highest level of structural scrutiny for seismic activity.

Other Lessons Learned:

Our area fared very well considering the size of the earthquake. Damage was minimal and no one was seriously hurt. Russell attributes this to two things. He says buildings in the area aren't that old, and the population isn't that dense.

The largest earthquake ever was a 9.5 in Chile. The earthquake in Louisa was a magnitude 5.8. That's the second largest Virginia earthquake in history. The largest was in Giles County in 1879, with a 5.9 magnitude.

Virginia's earthquake was not near a plate boundary. Central Virginia does have seismic activity.

Intensity of an earthquake is measured by the structural damage and human response.

Magnitude is measured by the energy released. On the East cost we use the Moment Magnitude Scale versus the commonly known Richter scale.

There have been 175 earthquakes in the Central Virginia Seismic Zone in the last 235 years. That's an average of one every 16 months.

On the East coast, especially our area of Virginia, damage can be felt more easily because the rock is more dense, so the vibrations travel better.  Soil conditions can also impact intensity. That explains why DC saw so much damage. They have thicker soil there.

The largest aftershock is usually 1 magnitude less than the earthquake. So, Russell says he thinks we already saw the biggest aftershock, as they tend to decay with time as the aftershocks release stress on the fault. That doesn't mean a bigger one can't happen. Remember, earthquakes aren't predictable.

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