A HUGE earthquake is predicted for Chile, after a major tremor earlier this year failed to relieve seismic stresses that have been building for 140 years.
The magnitude 8.2 Iquique quake on 1 April killed six. Now two separate analyses say worse is to come.
鈥淓ven though a very large quake has already happened this year, the hazard has not vanished,鈥 says of the US Geological Survey in Golden, Colorado. 鈥淭he issue now is communicating that,鈥 he says, 鈥渁s the tendency would be for people to think the quake has passed.鈥
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The risk zone stretches for 500 kilometres along much of Chile鈥檚 coastline, where the Nazca tectonic plate in the Pacific burrows eastwards beneath the South American plate.
Strain has been building up since the last megaquake, . But Hayes鈥檚 analysis suggests the April quake did not release the tension along at least two-thirds of this part of the plate boundary. The 200 kilometres south of Iquique is at most risk (). 鈥淓nough stress has been stored since 1877 to cause a quake of 8.5, so it means the hazard remains high,鈥 says Hayes.
鈥淓nough stress has been stored to cause a quake of magnitude 8.5, so the hazard remains high鈥
It could be as large as magnitude 8.9, forecasts Bernd Schurr of the German Research Centre for Geosciences in Potsdam, Germany ().
鈥淲e really don鈥檛 know how exactly that missing strain will ultimately be released,鈥 says of the University of California, Santa Cruz. 鈥淚t could be in smaller earthquakes, slow slip events, or in a much larger one.鈥
Fortunately Chile has good systems for responding to earthquakes, says of the University of Chile in Santiago, a co-author on both papers. It holds major evacuation drills involving thousands of people. In coastal regions, evacuation sirens warn of impending tsunamis, and alerts are sent to cellphones and through Twitter.
This article appeared in print under the headline 鈥淐hile is facing yet another megaquake鈥
