Earthquakes and Tsunamis

First off, thoughts are with anyone caught up in, or affected by,  this morning’s earthquake and the resulting tsunami near Japan.  There seems to be a fair amount of activity along the Pacific Plate Boundaries this year.  I thought i would compile a list of useful and interesting resources in and around the subject. This is very much work in progress, so if you have a link to a resource that you think would be useful to add, please leave a comment and i will add it to the post.

Japan 11th March 2011

From the USGS website:

“The 03/11/2011 earthquake (preliminary magnitude 8.9) near the east coast of Honshu, Japan, occurred as a result of thrust faulting on or near the subduction zone interface plate boundary between the Pacific and North America plates. At the latitude of this earthquake, the Pacific plate moves approximately westwards with respect to the North America plate at a velocity of 83 mm/yr. The Pacific plate thrusts underneath Japan at the Japan Trench, and dips to the west beneath Eurasia. The location, depth, and focal mechanism of the March 11 earthquake are consistent with the event having occurred as thrust faulting associated with subduction along this plate boundary. Note that some authors divide this region into several microplates that together define the relative motions between the larger Pacific, North America and Eurasia plates; these include the Okhotsk and Amur microplates that are respectively part of North America and Eurasia.”

Some links from the Earthquake that happened off the coast of Hunshu, main quake epicentre was at about 25km.

USGS details on the magnitude 8.9 quake

USGS list of recent activity in Pacific, at the time of writing there were over 20 registered aftershocks up to 7.1 magnitude oin strength.

Tsunami map

Image courtesy of NOAA (http://1.usa.gov/dJgLcF)

Another tsunami time travel map this time from surf-forecast.com

Image courtesy of www.surf-forecast.com

New Zealand -21st February 2011

Magnitude 6.3 but at relatively shallow depth (< 5km) the epicentre was very close to Christchurch and caused extensive damage.

From USGS page

“The February 21, 2011 South Island, New Zealand earthquake occurred as part of the aftershock sequence of the M 7.0 September 3, 2010 Darfield, NZ earthquake. The February 21st earthquake involved oblique-thrust faulting at the easternmost limit of previous aftershocks, and like the mainshock itself is broadly associated with regional plate boundary deformation as the Pacific and Australia plates interact in the central South Island, New Zealand.

This latest shock is significantly closer to the main population center of Christchurch, NZ, than is the September 2010 mainshock, in the vicinity of several other moderate (M 4 to 5) sized aftershocks located east of the main rupture zone of the 2010 event. There is no specific structure directly linking this event to the main fault of the 2010 mainshock, although there have been numerous aftershocks along generally east-west linear trends extending east from the end of the previous rupture. The north or north-east trends to the possible fault planes and the oblique thrust faulting mechanism as seen in the focal mechanism solution may reflect an association with similarly-trending faults previously mapped in the Port Hills region, just to the south of Christchurch.”

More inforamation can be found on the USGS information page

General

USGS site – showing the recent earthquakes

Major Earthquakes since 1900 – as listed on ShareGeo Open, check metadata for date of last update.

USGS feed – get near real-time data on earthquakes from the USGS.

Add a resource?

If you have more links to useful resources, please add them to the comments and i will add them into the main post.

About Addy Pope

Addy is a member of the GeoData team at EDINA and work on services such as GoGeo, ShareGeo and the FieldtripGB app. Addy has over 10 years experience as a geospatial analyst. Addy tweets as @go_geo
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