FEBRUARY 28, 2001 NISQUALLY EARTHQUAKE

Time of Occurrence (GMT): Wednesday February 28, 2001 at 18:54:32.78 Z
Time of Occurrence (PST): Wednesday February 28, 2001 at 10:54:32.78 AM

Depth (km) 52.40
Magnitude (Mw) 6.8 - Moment magnitude from the USGS National Earthquake Information Center.

Location 47.1525N 122.7197W

    17.6 km  NE of Olympia, WA
    23.7 km WSW of Tacoma, WA
    57.5 km SSW of Seattle, WA

Name of data file: 01022818543p

SHAKING INTENSITIES

Shake Map: Instrumental Measurements of Shaking Intensity
Community Internet Intensity Map: Human Reports of Experienced Shaking Intensity - By Zip Code
Peak Ground Acceleration Map: Preliminary map showing peak accelerations on mapped stations.

EARTHQUAKE REPORTS

Nisqually Earthquake Information Clearinghouse - Damage and Economic Loss Reports, Photo Galleries, Geotechnical Information, Engineering Reports
Natural Hazards Observer, May, 2001 - The Impact of Project Impact on the Nisqually Earthquake
Aftershocks of Nisqually earthquake
Nisqually links and Graphics from the USGS
Ground Deformation Map: - Preliminary locations of liquefaction and landslide sites.
Eyewitness account from Harbor Island - From Bob Norris, USGS

REPORT YOUR EXPERIENCE

Did you feel it? -- Fill out the Earthquake Felt Form here.
Did you see ground failures? Report landslides, sand boils, and ground cracks here.

MORE INFORMATION ON:

General

Deep Quakes In Cascadia - Basic Background on this type of earthquake

Cross Section showing Deep and Shallow suites of quakes, plus focal mechanisms in side view for 1949,1965, and 2001

Landslides General Info from the USGS

There is no Earthquake Prediction But there is The Charlatan Game

Technical

Preliminary Time History Accelerograms - ASCII FILES FOR ENGINEERS From the PNSN
Strong Motion Data - From the USGS NSMP (National Strong Motion Program)
Strong Motion Data - From the USGS Earthquake Hazards Program
Strong-motion Amplification Maps of the Tumwater and Lacey Quadrangles From the Washington Dept. of Natural Resources
GPS Geodetic Observations - From Rensselaer Polytechnic Institute
Time-Source Functions: From University of Tokyo and The University of Michigan

Special Pages from other organizations

Special Page from IRIS Incorporated Research Institutes for Seismology
EERI SPECIAL EARTHQUAKE REPORT - February 28, 2001
Pacific Northwest Geodetic Array Click on Link for Nisqually Earthquake - GPS modeling of what surface deformation is likely to result from this type of rupture
Comparison of Nisqually Earthquake to Jan. 17, 1994 Northridge earthquake from the Southern California Earthquake Center

More Links - Sand Rose, Thunderbird and Whale, Media Links

Detailed Information and Graphics about the Earthquake

Our data base of earthquake hypocenters contains information from the 19th century to the present. Included are:

A map of the Pacific Northwest showing the location of the earthquake (in red) plus prior earthquakes M > 3.5. Shallow events are black. Events deeper than 35 km are green.
A map showing a closer view of the earthquake and prior historical earthquakes with magnitude 3.5 or greater. Shallow events are black. Events deeper than 35 km are green.
A list of 10 big earthquakes preceding the mainshock that are closest to it and have a magnitude greater than 3.5. These are the most significant historical earthquakes in the vicinity of the mainshock (see the closer view map above).
A map showing the location of the earthquake relative to cities.
A map showing the location of the earthquake relative to the nearest seismograph stations that recorded it.
A detailed list of all earthquakes (M > 1.0) that occurred in the vicinity of the special earthquake in the previous two years. For the locations of these events see the next map.
A map of all earthquakes (M > 1.0) that occurred in the two years prior to the special earthquake. Detailed area shown is just few kilometers around the mainshock.
A List of the nearest 20 strong motion sites

Earthquake Mechanism

If sufficient P-wave first motion data are available, a fault plane determination for the earthquake will be available in the form of

A diagram of the fault plane solution(s). In some cases more than one solution may fit the data.
A table describing the fault plane solution(s) summarizing the characteristics of possible fault planes ("A" and "B") that are consistent with the recorded first-motion data.

Moment-tensor focal solutions from Oregon State University

Interactive view mechanism and smaller earthquakes with 3-D viewer. Similar to Figure 1 in SRL article: "Preliminary report on the Mw=6.8 Nisqually, Washington earthquake of 28 February 2001", SRL, V 72, May/June 2001.

LiveGraphics3D view of Nisqually earthquake focal mechanism

Preliminary Strong Motion Information

Strong-motion information from digital accelerographs.
Data files showing ground acceleration versus time from our ftp site (be sure to read the file called "readme" there).

This is file /SEIS/EQ_Special/WEBDIR_01022818543p/welcome.html last modified 10/8/02