Featured Research

from universities, journals, and other organizations

Japan earthquake caused a displacement of about two meters

Date:
April 8, 2011
Source:
Universitat Politècnica de Catalunya
Summary:
Researchers have estimated the ground deformation suffered in the area of Sendai, Japan, as a consequence of the earthquake of March 11 and its aftershocks, based on radar observations acquired by the Envisat satellite of the European Space Agency. According to this estimate, obtained over an area of approximately 300 x 100 km around the city of Sendai, the terrain has suffered a co-seismic deformation -- permanent deformation of Earth's surface -- associated with the earthquake of up to 1.69 m.

Coseismic deformation map of the Japan earthquake (March 11, 2011) overlapped to a Google Earth image.
Credit: Image courtesy of Universitat Politècnica de Catalunya

Researchers at the Institute of Geomatics -- Research Centre of the Polytechnic University of Catalonia (UPC) and the Government of Catalonia -- have estimated the ground deformation suffered in the area of Sendai, Japan, as a consequence of the earthquake of March 11, 2011 and its aftershocks. The estimate was derived from radar observations acquired by the Envisat satellite of the European Space Agency. According to this estimate, obtained over an area of approximately 300 x 100 km around the city of Sendai, the terrain has suffered a co-seismic deformation -- permanent deformation of Earth's surface -- associated with the earthquake of up to 1.69 m.

This value refers to the line connecting the satellite and the observed area, which is tilted about 41º from the vertical. The estimated value of 1.69 m is a deformation value relative to the observed area: the absolute deformation (i.e., calculated over an area not affected by the earthquake) is surely larger and cannot be estimated with this technique.

The minimum distance from the epicentre to the study area is 100 km approximately. At these distances the vast majority of earthquakes do not cause co-seismic deformation. However, in this case, there has been considerable deformation due to the exceptional magnitude of this earthquake.

The deformation can be seen in the map shown above, where the displacements are represented in a colour scale from black (no relative motion) to red (area of maximum deformation, which is the closest to the epicentre). There is relative deformation of 1.69 m from the area that appears black to the maximum area in red.

This study conducted by the Institute of Geomatics, and led by Dr. Michele Crosetto, head of the Remote Sensing Unit, is based on a well-known satellite-based microwave remote sensing technique called differential interferometry SAR (Synthetic Aperture Radar).

What does the observed deformation entail?

As mentioned above, the estimated 1.69 m deformation refers to the line connecting the satellite and the observed area. We know from other sources, such as measures of GPS (Global Positioning System), that the horizontal displacement has been of approximately 3 m eastwards, 0.5 m northwards and the vertical displacement varies between 0.5 and 1 m. The most important of these three components is probably the subsidence as it affects land elevation above sea level. Coastal areas are likely to be the most affected: in the worst case scenario, subsidence might lead to land loss. This is a phenomenon similar to what might result from climate change, although in this case, land would be lost as a result of sea-level rise.

How were the results derived?

SAR interferometry is a remote sensing technique used to monitor surface deformations. This technique, based on the analysis of SAR satellite data, has been used in various applications such as studying the dynamics of glaciers, earthquakes, volcanoes, mining, civil works, landslides and deformations due to exploitation of aquifers.

The results of this study were obtained using SAR data from the sensor ASAR mounted on the satellite Envisat of the European Space Agency. Specifically, in this case, two SAR images acquired before (19/02/2011) and after the seismic event (03/21/2011) have been used.


Story Source:

The above story is based on materials provided by Universitat Politècnica de Catalunya. Note: Materials may be edited for content and length.


Cite This Page:

Universitat Politècnica de Catalunya. "Japan earthquake caused a displacement of about two meters." ScienceDaily. ScienceDaily, 8 April 2011. <www.sciencedaily.com/releases/2011/04/110407121640.htm>.
Universitat Politècnica de Catalunya. (2011, April 8). Japan earthquake caused a displacement of about two meters. ScienceDaily. Retrieved September 15, 2014 from www.sciencedaily.com/releases/2011/04/110407121640.htm
Universitat Politècnica de Catalunya. "Japan earthquake caused a displacement of about two meters." ScienceDaily. www.sciencedaily.com/releases/2011/04/110407121640.htm (accessed September 15, 2014).

Share This



More Earth & Climate News

Monday, September 15, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Conservationists Face Uphill PR Battle With New Shark Rules

Conservationists Face Uphill PR Battle With New Shark Rules

Newsy (Sep. 14, 2014) — New conservation measures for shark fishing face an uphill PR battle in the fight to slow shark extinction. Video provided by Newsy
Powered by NewsLook.com
Pakistan's 'killer Mountain' Fails to Draw Tourists After Attack

Pakistan's 'killer Mountain' Fails to Draw Tourists After Attack

AFP (Sep. 12, 2014) — In June 2013, 10 foreign mountaineers and their guide were murdered on Nanga Parbat, an iconic peak that stands at 8,126m tall in northern Pakisan. Duration: 02:34 Video provided by AFP
Powered by NewsLook.com
Solar Storm To Hit This Weekend, Scientists Not Worried

Solar Storm To Hit This Weekend, Scientists Not Worried

Newsy (Sep. 11, 2014) — Two solar flares which erupted in our direction this week will arrive this weekend. The resulting solar storm will be powerful but not dangerous. Video provided by Newsy
Powered by NewsLook.com
The Ozone Layer Is Recovering, But It's Not All Good News

The Ozone Layer Is Recovering, But It's Not All Good News

Newsy (Sep. 11, 2014) — The Ozone layer is recovering thickness! Hooray! But in helping its recovery, we may have also helped put more greenhouse gases out there. Hooray? Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins