Magnitude 8.00 quake near Hokkaido, Japan

Last updated: 2018-03-26 17:50:56 UTC

Global view of quake


The Anza group at the University of California San Diego operates a broadband seismograph network consisting of 17 three component broadband seismograph stations centered near Anza, California (see map).

On Thursday, September 25th, 2003 at 12:50 PM (PDT) we recorded a quake (preliminary mb 8.00) located near the city of Hokkaido.

The tsunami alert for the coastal areas of Alaska has been canceled. Please see the National Weather Service Tsunami Warning Center for details.

If you felt the quake, the USGS would like to know. Please add to the USGS "Did you feel it?" page.

View the most recent map of local events near San Diego or a slightly wider regional view of events recoded by ANZA, or a map of events recoded by ANZA from around the globe.

Initial source parameters for the recent event are shown below. The epicentral distance (distance separating the epicenter and the closest station in the recording network) for Anza is 8274 km (74.42 degrees).

This map shows the mainshock (red star) and any associated aftershocks (orange stars). Anza network stations are blue triangles.

Global mecator event map

Latitude Longitude Origin time (UTC) Origin time (PDT) Depth (km) mb Author
42.1700 143.7200 9/25/03 (268) 19:50 9/25/03 (268) 12:50 80 8.00* QED
41.8300 143.5100 9/25/03 (268) 21:07 9/25/03 (268) 13:07 33 7.00* QED
41.90 143.64 9/25/03 (268) 20:10 9/25/03 (268) 13:10 33 5.50* QED
41.77 143.56 9/25/03 (268) 20:57 9/25/03 (268) 13:57 33 5.70* QED
42.2100 144.6400 9/26/03 (269) 06:26 9/25/03 (268) 23:26 10 5.60* QED
42.05 144.47 9/26/03 (269) 20:38 9/26/03 (269) 13:38 33 5.60* QED
42.44 144.39 9/29/03 (272) 02:36 9/28/03 (271) 19:36 33 6.50* QED
42.38 144.05 9/29/03 (272) 07:49 9/29/03 (272) 00:49 33 5.60* QED

* The location and magnitude determined for this event are preliminary and are subject to change upon further review of seismic data.

You may also view a plot showing

Of local interest:
We operate a broadband station on Mt. Soledad. At 13:01 (PDT) station SOL recorded the P wave from this event. Here is a view of that event as picked by our analyst. A pink "P" indicates a P wave arrival, a pink "S" indicates an S wave arrival.

3 component seismometer recordings at Soledad

View a larger image showing the waveforms recorded at Mt. Soledad.

Visit the IRIS website with additional links to seismic data for this event.

Virtual 3-D Model

You may download an interactive 3-D model by right-clicking (Windows) or CTRL-clicking (Mac) the image below and choosing "Download file to disk". The file has been compressed to ~2MB with gzip and must be expanded before use. To view the virtual model, you need to download iView 3D - a free viewer available from IVS for Windows, Mac, Linux, Sun and SGI platforms. Click here to download the viewer.

The model consists of the topography of Japan and the bathymetry of the surrounding ocean - dark purple regions are the lowest elevation, up to red regions that are the highest elevation. The model and its component parts have been accurately georeferenced. The hypocenter is plotted as a red sphere with the first two aftershocks plotted as smaller orange diamonds. Historical seismicity (from the PDE catalog) is plotted as small white points (they clearly define the subduction zone). Once the file has loaded into iView3D, navigation is accomplished by using the mouse. Click the left mouse button and drag left or right to rotate about the vertical axis. Click the left mouse button and drag up or down to rotate about the horizontal axis. Translations and scaling are both accomplished with either the middle or right mouse buttons in a two-step process.

iView3D scene image

Learn more about how to visualize seismic data.

News Links

To search the internet for more information about this event, click on the button below:

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Learn more about the Anza group (including who works here, other networks, nuclear tests in China/India/Pakistan).
Learn more about the ANZA network (includes more station information, research, etc).

URL: [Last updated: 2018-03-26 17:50:56 UTC]