Earthquakes

 

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A friend of mind sent out one of those “Do You Remember Where You Were  When….” posts on Facebook.   This one was about an earthquake :

 

M5.8 August 23, 2011 Mineral, Virginia

[ usgs.gov ]

 

On August 23, 2011 tens of millions of people along the East Coast suddenly felt the earth shaking from the largest earthquake in the eastern U.S. since the M5.8 earthquake in 1944 near Cornwall and Massena, New York.

 

The M5.8 earthquake occurred near Mineral, Virginia, and provided scientists with a rare opportunity to record, observe, and analyze data that had previously not been available for this part of the U.S. It was widely felt–from Maine to Georgia, west to Cincinnati, Cleveland, and Chicago, and southeastern Canada–over a broad area inhabited by one-third of the U.S. population. When the earth stopped shaking, more than 148,000 people reported their experience of the earthquake on the USGS Did You Feel It? (DYFI) site. The total economic losses from the earthquake were about $200-$300 million, which included millions of dollars in damage to the National Cathedral, the Armed Forces Retirement Home, and the Washington Monument in Washington D.C., as well as minor to major damage to almost 600 residential properties.

 

The earthquake occurred in what scientists refer to as the “Central Virginia Seismic Zone”, a region characterized by low-level seismicity since at least 1774. The zone extends east-west about 120km from the Fall Line to Blue Ridge and is about 100km wide in the north-south direction. Scientists who study eastern and central North America earthquakes often work from the hypothesis that modern earthquakes occur as the result of slip on pre-existing faults that were formed in earlier geologic eras and that have been reactivated under the current stress conditions. However, even though several small earthquakes are recorded each month in the Eastern U.S., there are usually not enough events to map out and associate them with a specific fault, so the hypothesis had not been well tested. For the fault that ruptured, however, geologic boundaries imaged above and below the fault do not show evidence for large displacement, which suggests that the fault may not fit the reactivation model and instead may be a relatively new fault.

 

The M5.8 earthquake initiated near the town of Mineral, Virginia, about 65 km northwest of Richmond, Virginia at a depth of about 6-8 km. The shaking was felt by approximately one-third of the U.S. population, and there were reports that it caused minor damage as far away as Charleston, South Carolina, roughly 600km from the epicenter. The shaking caused the first ever shutdown of a U.S. commercial nuclear power plant at the North Anna nuclear power facility located about 23km northeast of the epicenter. 

 

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An earthquake of the same size in the Eastern U.S. is felt more widely than one in the Western U.S. because seismic waves travel further in the colder, denser crust of the Eastern U.S. (Public domain.)

 

 

Where was I when this occurred?  Not a particularly interesting story……

 

It was after 1:00pm.  I always took a late lunch at Boxley, the company I worked for at the time.  I was sitting in the lunchroom, an area of the building where one wall was mostly all windows.  Our corporate office was right across the highway from our quarry in Blue Ridge, VA.  I was used to the blasting that regularly took place there.  Sometimes I would notice the plate-glass windows rattling a bit when that occurred.

 

I remember the sound from the windows that day.  The rattling was a little more intense than normal.  There had been no signal given right before a blast was to occur.   Something was just off…  I said to myself, “I bet that was an earthquake!”   A few others noticed something out of the ordinary and started milling around asking questions. “I bet that was an earthquake!!!”  I was right !!   

 

I called home to talk to my husband. He had taken the day off to assist the crew that was building a deck on the back of our house.   We live on Windy Gap Mountain, a little south of Roanoke.  He was totally unaware.  At an at an elevation of 2000 feet, no movement was detected.

 

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But, my “fondest” memory is of a prior earthquake here in Virginia.  That one occurred on December 9, 2003.  I had “tied the knot” with Brian and had been living in Roanoke for a little over two years at the time :

 

South of Goochland, along the James River, near Farmville, about thirty miles west of Richmond, the largest earthquake recorded in Virginia [at the time] occurred since the widespread use of modern seismic equipment in the 1970’s.  It was a shallow earthquake, three miles deep, probably the result of a rupture of the Lakeside Fault, at 3:59pm EST, and it was felt strongly over most of the State.  The quake was felt with usually long duration for a magnitude of 4.5 and a maximum intensity of VI. Many people reported a duration of shaking of up to 30 seconds. Although little or no structural damage occurred during the event, the U.S. Geological Survey reported that the trembles were felt in parts of North Carolina and Maryland.  Shaking was such that State government buildings were evacuated and inspected for damage. 

 

 

And that brings me back to where I was when this was occurring…..

 

I was at home….on the toilet !!!

 

TMI 😳😲😂😂😂😂😂 !!!

 

 

I was at home, sick, that day.  Just lying in bed, watching TV to pass the time. Nature called, and I got up to use the bathroom.  While siting there, the bypass-style mirrors in the medicine cabinet started rattling. That in itself was not too unusual.  We lived in Old Southwest, one of historical sections of the Roanoke.  Unfortunately, our house was located under one of the landing paths of the planes heading into the Roanoke airport.  But this rattling was a bit more intense than normal.  I said to myself, “that plane must be flying exceptionally low”….. but I heard no plane!!??!!   All of a sudden, the the whole house just kinda swayed back and forth one time!   I sat there, stunned for a few seconds.   I said to myself, “l must REALLY be SICK!!!”, as I made my way back to bed.  Ten minutes later, they broke in on the news with a Special Report saying there had just been an earthquake.  In a way, I was glad (it wasn’t just me) !!

 

Now THAT’S how you experience your first-ever earthquake !!!

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