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• Earthquakes• Monitoring Planet Earth• Earth’s Interior• Earth Processes

Science Educationand Public Outreach Through Seismology

Virginia EarthquakeRecorded at Weston Observatory

August 23, 2011

Magnitude 5.8 VIRGINIATuesday, August 23, 2011 at 17:51:04 UTC

There were no reported deaths, and scattered reports of minor injuries.

Air and train traffic was disrupted across the Northeast and mid-Atlantic.

Two nuclear plants in Virginia were immediately taken offline after the earthquake.

An earthquake in central Virginia was felt across much of the East Coast on Tuesday, causing light damage and forcing hundreds of thousands of people to evacuate buildings in New York, Washington and other cities.

Image courtesy of the US Geological Survey

VirginiaMagnitude 5.8

August 23, 2011

CaliforniaMagnitude 6.0

September 28, 2004

Adapted from Horton (2012)

(Data from U.S. Geological Survey, “Did you feel it?” website)

Where people reported feeling the effects of the Virginia earthquake (green) compared

with where a magnitude 6 earthquake in California was reported as being felt (blue).

But, then there are these “troublesome” (not always so little) earthquakes in the middle of the plates...

“Intraplate” Earthquakes

Plate TectonicsExplains MostEarthquakes

Boston College Educational Seismology Project:

Science Education Through Seismology

Hollis Center, MaineMagnitude 4.0

October 16, 2012

Boston College Educational Seismology Project

Weston ObservatoryGleason Public Library

Carlisle, MA

16 sec

16 sec

IPL

IPLGPL

BCDALK

Hollis Center, MaineMagnitude 4.0

October 16, 2012

Ipswich Public Library (IPL)

Gleason Public Library (GPL)

Boston College (BCD)

Alan’s Basement (ALK)

20 sec

Hollis Center, Maine: Magnitude 4.0, October 16, 2012

Magnitude 9.0Near East Coast of Honshu, Japan

Magnitude 6.5 – Bali Sea

Magnitude 6.5 - Japan Aftershock

Recorded at Weston Observatory

Magnitude 9.0 NEAR THE EAST COAST OF HONSHU, JAPANFriday, March 11, 2011 at 05:46:23 UTC

Japan was struck by a magnitude 9.0 earthquake off its northeastern coast on March 11, 2011: Largest earthquake ever recorded in Japan and the 4th largest earthquake ever recorded in the world.

. USGS

Part of houses swallowed by

tsunami burn in Sendai, Miyagi

Prefecture (state) after Japan was

struck by a strong earthquake off its

northeastern coast Friday, March 11,

2011.

New York Times

In downtown Tokyo, large buildings shook violently and there was severe flooding due to a tsunami generated by the earthquake.

Japan's worst previous quake was in 1923

in Kanto, a magnitude 8.3 quake that killed

143,000 people.

~16,000 fatalities

DateThe black squiggly lines represent ground motion.

Each line is one hour.

Seismic waves from magnitude 7.1 earthquake - Vanuatu (South Pacific).

TIME - MILITARY TIME IN GREENWICH, ENGLAND – GREENWICH MEAN TIME (GMT)OUR CLOCK IS BEHIND 5 HOURS IN WINTER (EST) AND IS BEHIND 4 HOURS IN SUMMER (DST).

minutes

Background noise caused by offshore waves, people walking by, ventilator fans, etc……. not earthquake waves.

The present hour is the last line on the screen.Present time

Costa RicaMagnitude 7.6

September 5, 2012

Boston College Educational Seismology Project

Devlin Hall, Boston College Gleason Public LibraryCarlisle, MA

Hurricane Sandy Recorded by Seismograph at Devlin Hall, Boston College

October 28 October 29 October 30

October 31 November 1

Sandy enters Boston area

Sandy leaves Boston area

Queen Charlotte Islands Earthquake, Magnitude 7.7

Magnitude 6.3Aftershock

Hurricane Sandyin Boston Area

A fault about the size of New England moved about 40 ft during about 2 min.

03/11/11-04/14/11, M≥6 (Aftershocks)

+ 1973-1999, M≥5 (Background Seismicity)03/11/11, M=9.0 (Main Shock)

Fault Plane

Fault Plane of Japan Earthquake Plotted on Map of New England

Japan Mega-Quake

A fault about the size of Boston moved about 1 ft during a few seconds.

August 23, 2011 - Magnitude 5.8 Earthquake in Virginia

Gleason Public LibraryCarlisle, MA

Magnitude 7.0 Earthquake in Haiti - January 12, 2010

Photos from: CNN.com and MSN.com

~316,000 fatalities

Magnitude 7.0 Earthquake in HaitiRecorded at Weston Observatory

January 12, 2010