Virginia Earthquake of 2011, Aug 23

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Discussion Overview

The discussion revolves around the 5.8 magnitude earthquake that occurred in Virginia on August 23, 2011. Participants share their experiences of feeling the quake across various locations, discuss its geological context, and reference historical earthquakes in the region.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested
  • Historical

Main Points Raised

  • Some participants note the earthquake's magnitude varied in reports, initially stated as 5.8, then 5.9, and later reverted to 5.8.
  • Several individuals describe their personal experiences of feeling the quake, with varying intensities and durations reported.
  • Some participants express surprise at the earthquake's occurrence, citing the relative inactivity of the Appalachian region in terms of seismic activity.
  • There are mentions of historical earthquakes in Virginia, including a significant event in 1897, and discussions about the geological history of the area.
  • Some participants report discrepancies in USGS data regarding the earthquake, indicating different sources may have reported varying details.
  • Several participants discuss the impact of the quake, including reports of shattered windows and concerns about potential damage in various locations.
  • There is a reference to other recent seismic events, including an earthquake in Colorado, which some participants connect to the discussion.

Areas of Agreement / Disagreement

Participants generally share their experiences and observations, but there is no consensus on the specifics of the earthquake's effects or the accuracy of the reports. Multiple competing views and uncertainties remain regarding the magnitude and impact of the quake.

Contextual Notes

Participants mention limitations in the available data from USGS and the potential for discrepancies in reported magnitudes and effects. There is also a lack of clarity regarding the historical context of seismic activity in Virginia.

Who May Find This Useful

This discussion may be of interest to those studying geology, seismology, or individuals curious about regional seismic activity and historical earthquakes.

Hurkyl
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5.8 in Virginia

http://www.google.com/search?client...rceid=opera&ie=utf-8&oe=utf-8&channel=suggest

According to Wikipedia, this is the strongest earthquake since a similarly sized one in 1897.


http://earthquake.usgs.gov/earthquakes/recenteqsus/Quakes/usc0005ild.php#details . (Courtesy of Astronuc)

(note: official reports of the strength have varied, started at 5.8, went up to 5.9, and I think reports are back down to 5.8)
 
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Felt it in Boston...
 


A bit of surprise, since the Appalachian chain is not terribly active.

Maine has a few small ones here and there, and the most recent "swarm" has been attributed to tectonic rebound from deformation by the Laurentide ice sheet that scoured our landscape during the last ice age.

Thanks for the heads-up. I'll be watching the news tonight to get updates.
 


I was relatively close to last years 3.6 quake -- I'm not entirely sure how this one compared in my area. I think a little less violent, but more prolonged. (and I didn't discover google's "recent earthquakes" display at that time) (also, I'm half asleep for today's)
 


Not unexpectedly, USGS sites are jammed.
 


Felt it outside of Philly - my first. Didn't realize what it was at first.

Http://www.usgs.gov

Felt like 15 sec of 1 inch, side to side oscillations at around 80hz
 


Felt it in my office in NJ! Had to evacuate. (Now I've got to check the lab. Don't think it did any damage.)
 
Wow! People felt it that far away! I wouldn't have noticed a small one, even if it could be felt here. Heavy trucks rumbling down this back road cause enough light shaking that a small quake would go unnoticed.
 
I felt in Ontario. It was so weak that I couldn't tell if my bed is really moving back and forth or I am just feeling it.
 
  • #10


russ_watters said:
Felt it outside of Philly - my first. Didn't realize what it was at first.

Http://www.usgs.gov

Felt like 15 sec of 1 inch, side to side oscillations at around 80hz

Yeah my first as well. I actually thought I was getting sick because I felt dizzy for apparently no reason. Then I realized my desk was slightly shaking.
 
  • #11
Felt in the Jersey suburbs of Phila. I lived in Japan, so I'm used to it. This is not the first one that I felt in NJ, there was one around 1971.
 
  • #12
Apparently folks in the Hudson Valley felt it. I did hear a kind of a muffled boom (P-wave probably), but no lateral motion.

This is the event - http://earthquake.usgs.gov/earthquakes/recenteqsus/Quakes/usc0005ild.php

5.9 mag, near surface (< 1 mile), but poorly constrained.
 
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  • #13
Yea felt it in NYC as well. Didn't realize what happened until I saw the aquarium water sloshing around.
 
  • #14
Astronuc said:
Apparently folks in the Hudson Valley felt it. I did hear a kind of a muffled boom (P-wave probably), but no lateral motion.

This is the event - http://earthquake.usgs.gov/earthquakes/recenteqsus/Quakes/usc0005ild.php

5.9 mag, near surface (< 1 mile), but poorly constrained.
I wouldn't have noticed a "boom" either, since we are under the flight-path for military aircraft headed for Europe and the ME. When there are large troop-movements and/or lots of equipment being deployed in a hurry, there is a lot of rumbling overhead. Commercial aircraft are pretty quiet - military aircraft? Not so much.

When I was a kid, sonic booms were quite commonplace here. SAC had lots of fighters to escort their jet bombers, and their old re-built tankers (generally B-28s) and when those fighters had tanked up, they'd often put on a show for us kids getting back to escorting the bombers. Boom! Life anywhere near the old Dow AFB meant that your skies were constantly streaked with contrails.
 
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  • #15
Astronuc said:
Apparently folks in the Hudson Valley felt it. I did hear a kind of a muffled boom (P-wave probably), but no lateral motion.

This is the event - http://earthquake.usgs.gov/earthquakes/recenteqsus/Quakes/usc0005ild.php

5.9 mag, near surface (< 1 mile), but poorly constrained.

That link puts the depth at 1 km, +/- 7.4 km...:biggrin:
 
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  • #16
Didn't feel anything here in upstate South Carolina. I was in lab with students sitting quietly taking a quiz. Someone would have spoken up if they had felt something.

I see a report on cnn.com that someone in Raleigh NC felt a "small tremor." It must have petered out before it got here.
 
  • #17
We felt it hard here in Southern Virginia. I had a split second of vertigo before I felt the shaking.

Preliminary reports are there is no damage here at NASA - still waiting to hear from JLab.

News says there were shattered windows at UVA.

Only issues I have heard about are friends in Northern Virginia having issues with cell service.
 
  • #18
Odd, the USGS has another report apparently for the same quake, but with different data

http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/se082311a.html
http://earthquake.usgs.gov/earthquakes/eqinthenews/2011/usc0005ild/
 
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  • #19
Hurkyl said:
Odd, the USGS has another report apparently for the same quake, but with different data

http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/se082311a.html
http://earthquake.usgs.gov/earthquakes/eqinthenews/2011/usc0005ild/
It seems the discrepancy is the source reporting the event.

For the geeks that just have to know the history of earthquakes in Virginia.

http://www.virginiaplaces.org/geology/quake.html

The last "big one" in Virginia (about a 5.8 on the Richter scale) was on May 31, 1897, in Pearisburg, the county seat of Giles County. The judge in the courthouse adjourned a trial, jumped over the railing, and fled outside with everyone else as the courthouse rattled, brick walls cracked, and chimneys fell over. It was Virginia's most powerful recorded earthquake - but our recorded memory extend back only a few centuries, and the geologic history of the state extends back hundreds of millions of years. In 1959, Giles County was shaken again by a 3.8 temblor. More recently, windows were broken in a Veterans Day, 1975 earthquake in Blacksburg.
 
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  • #20
Not meaning to hijack from Virginia but there was a http://www.nytimes.com/2011/08/24/us/24earthquake.html" last night.
 
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  • #21
Hurkyl said:
Odd, the USGS has another report apparently for the same quake, but with different data

http://earthquake.usgs.gov/earthquakes/recenteqsww/Quakes/se082311a.html
http://earthquake.usgs.gov/earthquakes/eqinthenews/2011/usc0005ild/

First link: se082311a.html
Source Southeast U.S. Seismic Network
Event ID se082311a

Second link: usc0005ild
Source Magnitude: USGS NEIC (WDCS-D)
Location: USGS NEIC (WDCS-D)

They have to reconcile the two sets of data/recordings.
 
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  • #24
Why do I feel rickrolled?
 
  • #26
lisab said:
:smile:

How tragic!

:confused: You think the person could have handed it to someone who could have enjoyed an it while they ran for the hills... alone... :smile: :smile:
 
  • #30
Evo said:
Holy Moly!@!

That's going to cost upwards of a million dollars to repair that.

Definitely going to have to figure out how to re-engineer that whole structure.
 

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