January 31, 2011

Study Suggests Another Major Quake Could Hit Chile

The region of Chile that was rocked by an earthquake last February could be at risk for a larger series of tremors, according to a new study published online by the journal Nature Geoscience on Sunday.

The 2010 earthquake, which hit the Maule region of the South American country on February 27, "was not unexpected," according to researchers from Italy's National Institute of Geophysics and Vulcanology. "A clearly identified seismic gap existed in an area where tectonic loading has been accumulating since the great 1835 earthquake."

By comparing the most recent earthquake to previous seismic events in the region, they determined that the seismic gap "was only partially filled" by the tremors and that "a zone of high preseismic locking remains unbroken, inconsistent with the assumption that distributions of seismic rupture might be correlated with preseismic locking."

"Moreover, we conclude that increased stress on the unbroken patch may in turn have increased the probability of another major to great earthquake there in the near future," lead author Stefano Lorito and colleagues wrote in the Nature Geoscience paper.

Lorito told AFP via email that the area to the north and east of the city of Conception--"a zone quite close to the epicenter of the Maule 2010 event"--could experience an earthquake with a magnitude of "seven to eight" sometime in the foreseeable future.

According to the news agency, the fault analyzed by Lorito and colleagues has been responsible for six earthquakes since 1835, including the most powerful quake ever measured, a 9.5 magnitude event that is believed that have been responsible for as many as 6,000 deaths in 1960.

The 2010 earthquake reportedly lasted as much as three minutes and was felt in six different regions throughout Chile, affecting four-fifths of the country's populace. The event resulted in 521 fatalities and between $4 and $7 billion dollars in damage, while also causing blackouts that impacted more than 90% of the country and led to tsunamis that affected areas as far away as California and Japan.


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