23 August 2011

An earthquake has just occurred in central Virginia that I felt here. The quake occurred at 1351 and at 1354 I was laying on my bed with my head against the wall reading when the wall started moving behind me. I looked up and the picture hanging on the wall over my chest was swinging out from the wall and the water in the fish tank on top of the chest was sloshing back and forth. It seems to me that the major component of motion was in the E-W direction. I am estimating the duration of the shaking at 15-30 seconds. Given the time it took for me to confirm what was happening and what time I looked at my watch I probably felt it at around 1352-3 EDT.

USGS graphic

USGS graphic

USGS graphic

USGS graphic

USGS graphic

USGS graphic

USGS graphic

The area appears to be very rural with the epicenter out in the woods.

iQuakeLite graphic

iQuakeLite graphic

I reported the event on the USGS Did You Feel It page and they gaded the estimated intensity here as III (weak shaking, no damage).

I wonder if my MacBook Pro running the Quake-Catcher Network program in BOINC reported it.

Notify NYC ✆ swnalert@sendwordnow.com to Charlie
14:34 (16 minutes ago)

Alert issued 8/23/11 at 2:25 PM. The USGS is reporting a 5.8 magnitude earthquake near Virginia that has caused shocks in the New York City area. In the event of an emergency please call 9-1-1.

The sender provided the following contact information.
    Sender's Name: Notify NYC
    Sender's Email: notifynyc@oem.nyc.gov
    Sender's Contact Phone: 212-639-9675

Notify NYC ✆ swnalert@sendwordnow.com to Charlie
15:03 (1 hour ago)

Notification issued 8/23/11 at 3:00 PM. There are no reports of major structural damage, injuries, transportation, or utility service disruptions affecting New York City at this time. For the latest MTA information visit: http://www.mta.info.

The sender provided the following contact information.
    Sender's Name: Notify NYC
    Sender's Email: notifynyc@oem.nyc.gov
    Sender's Contact Phone: 212-639-9675

I checked into the network of cooperating siesmic stations on the eastern seaboard and managed to eventually get pictures of their recordings of the event.

USGS graphic

Orono, ME
University of Maine

Boston College graphic

Boston College

Boston College graphic

Smithfield, RI
Bryant University

Boston College graphic

New Haven, CT
Yale University

Boston College graphic

Westfield, CT

Boston College graphic

Binghamton, NY

Boston College graphic

Palisades, NY
Columbia University

Lamont-Doherty Earth Observatory graphic

Towson, MD

MD Geologic Survey graphic

Blacksburg, VA
Virginia Tech

VA Tech graphic

Columbia has a seismograph in Central Park so I was able to determine that I likely felt the shaking at 1352-3 EDT. I got information from it for both N-S and E-W shaking and it appears that the N-S component was stronger although I did not sense it at all.

Lamont-Doherty Earth Observatory graphic

Lamont-Doherty Earth Observatory graphic

Lamont-Doherty Earth Observatory graphic

USGS has compiled a tectonic summary explaining what actually happened.

USGS graphic

This quake occurred in a known seismically active region but this is the largest event to have occurred since the advent of reliable seismometers and larger than the estimate for the largest event since the 18th century.

The FEMA HazUS program produced the following impact probability assessmens.

This map from one of my many iPad earthquake programs shows the earthquakes that have occurred in New England since over the past year or so.

I also found while doing all this research, that Hurricane Irene is forecast to be up here on Sunday night. Currently Irene is a Category 1 hurricane but it is predicted to intensify into a major (Category 3-5) hurricane Wednesday night or Thursday.

NOAA graphic