8.2M Earthquake Rocks Chile, Tsunami Warning Issued; History of Quakes in LA Coast

An earthquake measuring 8.2 magnitude hit off Chile triggering a tsunami warning for the entire Latin America’s Pacific coast, the US Geological Survey said.

USGS said the quake, though very shallow with 10km depth below the seabed, the sub-tectonic movement may cause tsunami along the coast 86km (56 miles) north-west of the mining area of Iquique.

Similar earthquake measuring 8.8 hit off Bio-Bio shore on February 27, 2010 killing more than 547 people. Chile is also placed along the Pacific Ring of Fire, that witnesses frequent tectonic movement causing earthquakes.

Seismotectonics of South America:

The South American arc extends over 7,000 km, from the southern Chile to the Panama fracture zone.
It marks the plate boundary between the subducting Nazca plate and the South America plate, and the subduction process beneath is responsible for the uplift of the Andes Mountains, and for the active volcanic chain present along the deformation front.

Relative to a fixed South America plate, the Nazca plate moves north of eastwards at a rate varying from approximately 80 mm/yr in the south to approximately 65 mm/yr in the north causing complex changes in the geologic processes.

Most of the in the region are constrained to shallow depths of 0 to 70 km resulting from both crustal and interplate deformation, says USGS.

Since 1900, numerous magnitude 8 or larger earthquakes have occurred in the region, followed by devastating tsunamis, including the 1960 M9.5 earthquake in southern Chile, the largest instrumentally recorded earthquake in the world.

Other notable shallow tsunami-generating earthquakes include the 1906 M8.5 earthquake near Esmeraldas, Ecuador, the 1922 M8.5 earthquake near Coquimbo, Chile, the 2001 M8.4 Arequipa, Peru earthquake, the 2007 M8.0 earthquake near Pisco, Peru, and the 2010 M8.8 Maule, Chile earthquake located just north of the 1960 event.

Most of these earthquakes occur adjacent to the coastline between Peru and Chile, including the recent large intermediate-depth earthquake — the 2005 M7.8 Tarapaca, Chile earthquake.

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