The impact of the 2015 M8.3 Chile Earthquake

Wednesday’s (15 Sept) earthquake which stuck off the coast of Chile is at this time the largest earthquake of 2015 and has led to wide scale ground motion and caused a tsunami. In this post I will summarise some of the societal impacts which have already occurred, and some potential impacts which are being forecast. 

Generally, the number of recorded earthquakes exceeding M8.0 globally is in single digits (see graph below). Therefore, the probability of an earthquake measuring greater than M8.0 occuring in a particular locality could be classified as a relatively rare event (compared to many other perils facing society), even in highly seismically active areas like the coast of South America. When relatively rare events occur they can catch societies off guard and cause very large scale impacts (e.g. loss of life, high economic losses). This was the situation in 2010 when a M8.8 earthquake occurred just off the coast of Chile leading to 525 deaths and insured losses of between $4-7BN.

Recorded earthquakes 2005 – September 2015 (data from here)

Much has been made of the improvements in infrastructure resilience, early warning systems, and urban planning which have contributed to keeping the death toll much lower (12 so far) in this earthquake. This figure is at the lower end of the forecast death toll from the USGS Impact PAGER of 39% chance of between 10 – 100 deaths. Although the death toll is much lower, economic losses and social disruption are still likely to be immense.

The USGS Impact PAGER is forecasting a 50% probability of economic losses in the range of $100 – 1,000 million. The heaviest damage is being reported in Illapel (see map below) where several buildings have collapsed. Over 250,000 people are affected by power outages (Illapel and most of Coquimbo). About 1 million people were evacuated from coastal areas of Chile due to the threat from tsunami but many have now returned. The tsunami caused significant damage to port infrastructure and aquaculture (in Spanish)

Shakemap for 2015 M8.3 Chile earthquake (From USGS)

Where to next?

Affected areas will be beginning the arduous task of cleaning debris left behind by fallen buildings and tsunami debris. Experiences have shown that disaster clean-up can be extremely challenging, time consuming, and expensive activities.

Sector Baquedano Avenue of Coquimbo destroyed and flooded by the tsunami of 16 September 2015 (photo credit: Sfs90)

Follow me on twitter: @naturehazard or at The Geohazards Blog.

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