Could an Earthquake Hit the Lehigh Valley?
After the recent earthquake in Maine, what are the chances one could hit the Lehigh Valley?
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As far as natural disasters go, earthquakes tend to be far from the minds of Lehigh Valley residents. That is, of course, until a recent 4.0 magnitude earthquake in Maine brought the possibility closer to home.
That earthquake, as well as the one last year in Virginia, have several Lehigh Valley residents questioning whether an earthquake of similar magnitude could possible hit the Lehigh Valley.
So, could the Lehigh Valley experience an earthquake?
It's not very likely, says Dr. Larry Malinconico, associate professor of Geology and Geophysics at Lafayette College in Easton.
"The fact of the matter is that earthquakes tend to occur at active tectonic margins," said Malinconico. "The recent earthquake occurred on old faults that are reactivated for some reason, but it's rare."
While the Lehigh Valley does have some old fault lines, Malinconico says any activity along these lines would be extremely rare. "These local fault lines are from hundreds of millions of years ago. Any activity along these lines are fairly scattered."
That's not to say that the Lehigh Valley has been immune to earthquakes throughout history. The U.S. Geological Survey reports a few small to midsize earthquakes in our area, the last one of moderate magnitude hitting Sept 14, 1961.
As far as natural disasters go, Malinconico says that earthquakes should be near the bottom of our list.
"The biggest [natural disaster concerns for the valley] is flooding," he said, citing the recent flooding from Hurricane Irene as an example. "Earthquakes are nothing to worry about from a short-term or long-term perspective."
Rich Cranium
7:41 am on Friday, October 19, 2012
Pretty sure this happened already didn't it? I seem to recall an earthquake last year. So I would say that it is possible, likely? Probably not, but not impossible
Elizabeth Rich
10:36 am on Friday, October 19, 2012
Hi @Rich,
Thanks for writing in! The earthquake last year was in Virginia, we've included a link to our story from last year in this article.
Jennifer Rodgers
7:48 am on Friday, October 19, 2012
I remember that! But if I'm remembering correctly, its epicenter was in VA and we felt it here! I actually thought my kids were shaking the house and ran upstairs to find out what they were doing!
ted.dobracki
9:47 am on Friday, October 19, 2012
There was an earthquake in VA last summer that was felt in most of PA. I recall exactly where I was. We were driving along US 6 in northern PA on our way to the Grand Canyon of PA and heard a radio report about the quake. Of course, in the car, we hadn't felt it. But after walking around the park, and nobody seemed to be abuzz about the quake, we asked the young lady in the gift shop. She said she did feel something and was trying to find out more about what happened online.
Frank
11:42 am on Friday, October 19, 2012
We felt it here in SWT. Our sliding door windows were crackling.
Jay Impink
12:30 pm on Friday, October 19, 2012
Can an EQ "occur" in the Lehigh Valley? I would have to concur with Dr. Malinconio no "active" fault lines. BTW, I have a Earth/Space Geology BS plus 35 years teaching experience. But, you should
never say never. The comments all relate to activity centered elsewhere. If, an EQ were to be centered here in the LV, it would be a memorable event. Save your money from EQ insurance and invest in sinkhole insurance.
Heather Depew
2:46 pm on Friday, October 19, 2012
Absolutely in regards to sinkhole insurance. @Jay Impink: Let me ask your opinion, I am doing a paper for an environmental issues class. I want to do it on why sinkholes have been forming all over the Lehigh Valley. Do you know possible reasons?
Frank
4:57 pm on Friday, October 19, 2012
Heather, I can tell you the reasons. It's because of the high amount of limestone we have in our soil here. That, along with old pipes running through the ground. These are the main reason for the sinkholes.
tamarya
7:30 pm on Friday, October 19, 2012
If we have an EQ centered in the L.V we won't need the insurance our house would just collapse on us since it is a mobile home, because there probably is no way I am getting out before it falls apart on me.
Heather Depew
2:49 pm on Friday, October 19, 2012
There is a fault line that goes under Lehigh University. In the last 1990's there was an earthquake but it was a 1 on the Richter scale. If the earthquakes that occurred in Maine and Virginia are due to fault lines becoming reactivated, couldn't that happen right here as well?? I think it could be a possibility.
Jay Impink
3:58 pm on Friday, October 19, 2012
Heather, the Lehigh Valley is underlain by limesstone which can be dissolved by groundwater. This explains the occurrance of caves in the area (lost river, crystal). Belive me, there are plenty more down there. Usually, the overlaying rock is
bouyed up by the relatively high water table but occasionally the water table drops and these underground caverns collapse and we see a sinkhole at the surface. Just look at farm fields and you
can see depressions, these are sometime called ghost lakes they are the visual clues to a collapse below. Groundwater is all so important. When the Friedensville zinc mine was operating, they pumped so much water many sinkholes formed in.the in the surrounding valley. When they stopped in the early 80's the subsidence also did. I can say more.
Heather Depew
4:33 pm on Friday, October 19, 2012
Ah, the mines pumping water....were they pumping actual aquifers? Thank you so much for your knowledge. I wanted to do something on the local area for my research paper, so I am glad that you have shared this with me.
Jay Impink
5:39 pm on Friday, October 19, 2012
I'm not so sure about the aquifers, but the vertical shaft went down over 2000 ft. I was down there on the early 70's. Creepy place with huge pumps running ankle deep water on the floor. Remember, we were nearly 2000 feet below the water table. This is not directly transferrable to other parts of the valley, but if water table goes down, so does the land. Remember Heather, most if not all of the urban sinkholes are the result of failure of waterpipes.
Jay Impink
5:43 pm on Friday, October 19, 2012
BTW Heather, after 2 years of retirement it feels good to disseminate some information. I should be thanking you.
Heather Depew
11:50 am on Saturday, October 20, 2012
You're welcome!!! Any time!
93GEO-Metro
6:36 pm on Friday, October 19, 2012
But after living here in Nazareth all my young life, whenever the cement mills would blast on the "Main Line" our whole house would shake and we did experience several cracked windows because of it. So when we felt the recent tremors, I thought one of the mills were blasting again and it was no big deal for me.
Yertle1
11:04 pm on Friday, October 19, 2012
There was a quake in the LV in 1961
Yertle1
5:38 pm on Saturday, October 20, 2012
In reference to the Friedensville mine water, decades ago Dr Trembley, a biology professor wrote weekly articles in the Morning Call
When the mines stopped pumping the threat of the water rising unprohibited was a concern.
His thoughts were that the water could possibly rise to area's that were now largely inhabited. There is no record of the land area prior to the zinc mine operation. If the water would return to its centuries old locations, he said people could wake up to find there house (and them) in the middle of a pond or stream.
He also said it could be a surprise along the new (at the time not completed) I-78.
Luckily the township is now pumping and using the water and it is in check.