Wednesday 16 October 2013

Magnitude 7.1 Earthquake on Bohol Island, the Philippines.

The United States Geological Survey recorded a Magnitude 7.1 Earthquake at a depth of 20 km on Bohol Island in the Philippines slightly after 8.10 am on Tuesday 15 October 2013. Earthquakes of this size in populated areas are extremely dangerous, and this one is known to have caused at leas 93 casualties (69 on Bohol and the remainder on neighbouring Cebu and Siquijor Islands) and well as causing the total or partial collapse of a large number of buildings, including homes, churches and commercial properties. Since the initial event there have been dozens of aftershocks, many exceeding Magnitude 5.0, contributing to the problems caused by the initial quake.

Damage to buildings in Cebu City on Cebu Island. AFP.

The geology of the central Philippines is Complex. The west of Mindanao Island is located on the Banda (or Sunda) Microplate, and the east on the Philippine Plate, which is being subducted beneath the Sunda (or Banda) Microplate along the central part of the island. Immediately to the east of the Island the Pacific Plate is being subducted along the Philippine Trench. The subducting Philippine Plate passes under the islands if Bohol and Cebu as it sinks into the Earth. This is not a smooth process, an the plates constantly stick together then break apart again as the pressure builds up, resulting in Earthquakes.

The approximate location of the 15 October 2013 Bohol Island Earthquake. Google Maps.

Follow Sciency Thoughts on Facebook.