Earthquakes in Australia - Expect a big one

Normal view (turn off text only mode)
You are here:

NATHAN Risk Suite - Munich Re

Earthquakes in Australia – Expect a Big One

Earthquakes in Australia are infrequent and mostly moderate in size. At first glance, this appears to be a much more comfortable situation than in New Zealand, Japan or the United States. However, on closer examination the picture looks different: earthquakes in Australia could cause insured losses in the same order of magnitude as in the highest-exposed regions worldwide.

Australia is not known to be an earthquake hotspot – but neither was Christchurch in New Zealand. As it turned out, in Christchurch in 2010/2011 an unexpected series of severe earthquakes with a magnitude of up to 7.1 surprised even the experts and destroyed large parts of the city – it was one of the most expensive insured natural catastrophes in history.

Liquefaction - what happened in Christchurch?

In the period between the first earthquake on 4 Sept 2010 and late 2012 the Canterbury region and the city of Christchurch experienced strong earthquakes. Because of the soft soil in the region liquefaction effects had a tremendous impact on damages.

Since Australia is not located at the margins of the tectonic plates, where 90% of the world’s seismicity occurs, many Australians are not aware that earthquakes are is a peril  we need to worry about – but maybe we should.

The Australian continent experiences small earthquakes all the time because the Indo-Australian tectonic plate is being pushed north and thus collides with other plates. This leads to a build-up of mainly compressive stresses that are released in shallow earthquakes.

Earthquakes can also occur anywhere in Australia

Although earthquakes can occur anywhere in Australia, this seismicity is spatially heterogeneous; some regions have significantly increased seismic activity. Statistical analyses on recorded earthquakes show that events with a magnitude similar to or higher than that in Newcastle in 1989 (magnitude 5.6) can be expected every two years, with a magnitude of 6.0 or more every five years on average. Fortunately most of them happen in not unpopulated or sparsely populated regions.

Our models show that regions of elevated seismicity are in close proximity to most of the major conurbations (Perth, Adelaide, Melbourne and Sydney). For each individual area, the seismicity is too low for a robust statistical analysis of the probability of a severe event right underneath a city or the maximum size of such an event.

What we do know is that each of the cities has the potential to be hit by earthquakes bigger than a magnitude of 6. Earthquakes like those in Christchurch should not come as a surprise and are very realistic scenarios. Many buildings in Australia will not survive such strong ground motions.

It is only a matter of time an in Australia an  earthquake will hit one of the bigger cities. The only questions that remain are: when and how severe? The financial impact might be tremendous. Read on.

Dr. Astrid Zwick und Stefan Lämmle, Munich Re.

Natural hazards in Australia and New Zealand

Floods, cyclones, hailstorms, bushfires, earthquakes and volcanic eruptions – get a detailed overview of the science of natural hazards in Australia and their financial impacts.

Download

Risk factors

NATHAN Risk Suite - Munich Re

Climate change, natural climate variability, natcat and resilience – find out about the relevant risk factors.

Understanding risk

NATHAN Risk Suite - Munich Re

Risk is the product of (the probability of) a hazard and its adverse consequences. See how it affects your business.

Contact


Main Navigation
Service Men
Accessibility

Note


This publication is available exclusively to Munich Re clients. Please contact your Client Manager.