[IGSMAIL-6357] Magnitude 8.8 earthquake offshore of Japan
Jeff Freymueller
jeff.freymueller at gi.alaska.edu
Thu Mar 10 23:45:30 PST 2011
A very large earthquake (M8.8) struck northern Japan about 2 hours
ago. Details below from the USGS. This is similar in size to the 2010
Maule earthquake in Chile. Based on the aftershock locations showing
today, it appears to have involved a roughly 500 km long rupture,
extending as far south as Tokyo. Check the news for details of damage,
tsunami, etc. I don't have any information from Japan yet, although I
have emailed some friends there.
It is likely that this earthquake has caused a significant
displacement of every GPS site in northern and central Japan, plus
Korea and parts of northern China. As with the Maule earthquake, it is
likely that measurable displacements extend as far as several hundred
km to perhaps more than 1000 km from the rupture zone.
Several IGS08 core sites were certainly or possibly displaced, and
other sites used by the IGS (such as Usuda and DAEJ) are likely to
have been displaced.
TSKB definitely, decimeters to meters
BJFS maybe mm-cm?
KHAJ maybe mm-cm?
TNML maybe mm-cm?
Non-linear motion with time will almost certainly follow for several
years or more for sites affected by the earthquake.
IGS centers should look very carefully at solutions and coordinate
estimates for all sites within a sufficient radius around the
earthquake rupture before releasing orbit or solution products.
Within a day or so, preliminary slip models from the USGS and other
sources should be available, based on seismic recordings. For the
Maule earthquake, these models predicted displacements fairly
accurately in the far field (hundreds of km from the rupture),
although they did not work so well for near field. I suspect
performance will be similar in this case.
Jeff
Begin forwarded message:
> From: ens at usgs.gov (USGS ENS)
> Date: March 10, 2011 9:28:35 PM AKST
> To: jeff at kiska.giseis.alaska.edu
> Subject: 2011-03-11 05:46:23 UPDATED: (M 8.8) NEAR EAST COAST OF
> HONSHU, JAPAN 38.3 142.4 (dc9d)
> Reply-To: <ens at usgs.gov>
>
> == PRELIMINARY EARTHQUAKE REPORT ==
>
> ***This event has been revised.
>
>
> Region: NEAR EAST COAST OF HONSHU, JAPAN
> Geographic coordinates: 38.322N, 142.369E
> Magnitude: 8.8 M
> Depth: 24 km
> Universal Time (UTC): 11 Mar 2011 05:46:23
> Time near the Epicenter: 11 Mar 2011 14:46:23
> Local standard time in your area: 11 Mar 2011 05:46:23
>
> Location with respect to nearby cities:
> 130 km (81 miles) E (86 degrees) of Sendai, Honshu, Japan
> 179 km (111 miles) ENE (68 degrees) of Fukushima, Honshu, Japan
> 188 km (117 miles) SE (145 degrees) of Morioka, Honshu, Japan
> 376 km (234 miles) NE (37 degrees) of TOKYO, Japan
>
>
> ADDITIONAL EARTHQUAKE PARAMETERS
> ________________________________
> event ID : US c0001xgp
>
> This event has been reviewed by a seismologist at NEIC
> For subsequent updates, maps, and technical information, see:
> http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/usc0001xgp.php
> or
> http://earthquake.usgs.gov/
>
> National Earthquake Information Center
> U.S. Geological Survey
> http://neic.usgs.gov/
>
>
> DISCLAIMER: https://sslearthquake.usgs.gov/ens/help.html?
> page=help#disclaimer
>
>
> This email was sent to jeff at giseis.alaska.edu
>
> You requested mail for events between -90.0/90.0 latitude and
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Dr. Jeffrey T. Freymueller Office: 907-474-7286
Geophysical Institute Fax: 907-474-7290
University of Alaska, Fairbanks Home: 907-479-3550
PO Box 757320 Cell: 907-378-7556
Fairbanks, AK 99775-7320 email: jeff.freymueller at gi.alaska.edu
URL: http://www.gps.alaska.edu/jeff/jeff.html
Download Alaska GPS data: ftp://gps.alaska.edu/pub/gpsdata/
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