Geological evidence for past earthquakes in Tokyo region

January 31, 2012

In 1923, a magnitude 7.9 earthquake devastated the Tokyo area, resulting in more than 100,000 deaths. About 200 years earlier, in 1703, a magnitude 8.2 earthquake struck the same region, causing more than 10,000 deaths.

These earthquakes, which occurred just south of the area hit by the March 2011 , were produced by slips on the boundary between the subducting Philippine Sea plate and the overlying plate.

To estimate the average recurrence time between earthquakes in this region, and thus learn more about , scientists need to know when earthquakes occurred before 1703. There are few historical documents describing earlier earthquakes, though some records indicate that earthquakes occurred in 1293 and 1433.

To learn more about past earthquakes, Shimazaki et al. analyzed cores about 2 meters (6.6 feet) long from eight tidal flat sites on the Miura Peninsula in Japan. Their cores contained layers of shell-filled gravel that the researchers infer were deposited by tsunamis associated with the 1703 and 1923 earthquakes, as well as a third layer of tsunami-deposited material. The authors used dating to date the third event to sometime between 1060 C.E. and 1400 C.E. That is consistent with a large earthquake having occurred in 1293. If so, that indicates that the recurrence interval of these earthquakes varies from about 200 to about 400 years. The study could help scientists assess the earthquake and tsunami hazard in the Tokyo area.

Explore further: 1755, 2007 European earthquakes compared

More information: Geological Evidence of Recurrent Great Kanto Earthquakes at the Miura Peninsula, Japan, K. Shimazaki and H. Y. Kim, Journal of Geophysical Research-Solid Earth, doi:10.1029/2011JB008639 , 2011

Related Stories

1755, 2007 European earthquakes compared

July 2, 2007

An Italian-led team of seismologists has conducted a study comparing a 2007 earthquake off southwestern Portugal with a similar 1755 earthquake.

Ill. earthquake a wake-up call

April 20, 2008

A U.S. seismologist said the earthquake that jolted the Midwest Friday is a reminder of the risks seismic events pose outside familiar quake areas.

GPS data reveals more on mega-thrust earthquakes

April 29, 2011

(PhysOrg.com) -- New GPS data of the 2010 earthquake that devastated parts of Chile and killed over 500 people is revealing new clues about large earthquakes such as the quake in Chile and the magnitude 9.0 earthquake that ...

Relationship between two recent New Zealand earthquakes

September 26, 2011

The relationship between two earthquakes that took place near Christchurch, New Zealand, in September 2010 and February 2011 is examined in a paper published in Scientific Reports. The findings suggest that the first earthquake ...

Japan and New Zealand were hit hardest by earthquakes in 2011

January 19, 2012

Last year, earthquakes and their consequences, such as tsunamis, landslides, and ground settlements, caused a damage of 365 billion US dollars. Hence, 2011 was the year with the so far highest economic losses due to earthquakes. ...

Recommended for you

Clues from ancient Maya reveal lasting impact on environment

September 3, 2015

Evidence from the tropical lowlands of Central America reveals how Maya activity more than 2,000 years ago not only contributed to the decline of their environment but continues to influence today's environmental conditions, ...

Climate ups odds of 'grey swan' superstorms

August 31, 2015

Climate change will boost the odds up to 14-fold for extremely rare, hard-to-predict tropical cyclones for parts of Australia, the United States and Dubai by 2100, researchers said Monday.

1 comment

Adjust slider to filter visible comments by rank

Display comments: newest first

rwinners
not rated yet Jan 31, 2012
Talk about a science being in it's infancy... Look at Google Earth. One can see the interactions of plate tectonics. I seriously doubt that this has changed in millenia... er.. how does one express ... oh.. thousands of millenia.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.