Tremor Sequence Of Chilean Coast

A 7.1 magnitude tremor has just been reported some 30km off the coast of Valparaiso, Chile.  The quake was broadly felt in the capital of Santiago, which is 100km inland from the coastal city.  Severe damage has yet to be reported.  Chilean authorities initially ordered a preventative evacuation of the coastal area near Valparaiso, around 60 miles west of Santiago, in case of a tsunami, but cancelled it shortly afterward.  This tremor closely follows an abnormal sequence that registered eight magnitude 5 earthquakes followed by 6 “aftershock” tremors measuring between 5.0 and 6.0 in magnitude.  In terms of magnitude and frequency, this sequence is unique since aftershock tremors are generally much weaker than the initial quake.  Seismic activity is expected to gradually increase of the Nazca plate continues to subduct under the deformed and faulted South American plate.  

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