World Experiencing Cycle of Giant Quakes - A.M. Best Media Interview of Paul Thenhaus

December 28, 2011

A.M. Best Media Interviews Paul Thenhaus, Senior Geologist, EQECAT

A.M. Best Media Interviews Paul Thenhaus

Paul Thenhaus, Senior Geologist of EQECAT, was a guest on A.M. Best Media, a worldwide insurance-rating and information agency.

Watch the Paul Thenhaus interview where host John Weber addresses recent major earthquakes and if earthquakes of major intensity cluster in time around the world.

Weber asks about mega thrust earthquakes and EQECAT's recently released white paper that explores the temporal clustering of major earthquakes worldwide and their impact to the insurance and reinsurance industries.

Thenhaus explains how mega thrust earthquakes occur between the boundaries of two tectonic plates with low-angle thrust faults and large surface areas that combine to produce the largest earthquakes worldwide. He explains how shifts in Japan's tectonic plates produced the 2011 Tohoku Japan earthquake and tsunami and why quakes in the well known Ring of Fire produce some of the largest earthquakes worldwide. He explains that earthquakes on the San Andreas fault system of California occur on vertical strike slip faults with less surface area and can not produce magnitude 9.0 earthquakes.

Implications of Earthquake Clustering Research

World's Largest Earthquakes since 1900

World's Largest Earthquakes since 1900 (via USGS)

Thenhaus addresses how the white paper brings attention to a research issue suggesting an active cycle of large earthquake activity. Scientific observations indicate a record rate of large earthquakes occurrences globally beginning with the giant magnitude 9.2 1004 Sumatra earthquake and tsunami.

There is a possibility that these extremely large earthquakes may cluster temporally over time - over periods of perhaps 15 years.

EQECAT scientists saw the Tohoku, Japan earthquake (March 2011) and the 8.8 Maule, Chile earthquake (February 2010) occurring close together and noted there have been 3 large earthquakes in the past seven years. The white paper addresses these findings and possible implications.

Findings & The Insurance Industry

Weber asked,

"What does this white paper mean to the insurance industry?"

Thenhaus explains that 

"Over some time periods of a decade or two decades, we might expect higher frequencies of these large mega thrust earthquakes in a place like the circum-Pacific region."

He explains that what it means for the insurance industry is still open for discussion in terms of preparing for such a scenario of increased occurrence frequency over a decade or more compared to some long-term average rate. It's not proven that clustering does exist. There is no physical reason that can explain the global temporal clustering. However, it does appear that we are in a period of increased great and giant earthquake frequency. It might be over the occurrence of the Tohoku Japan earthquake. But then again, it might not be. 

Thenhaus concludes that it's:

"...up to discussions between both the insurance industry and modelers as to how this might be taken into account in our future models to look at the implications of these increased frequencies in terms of losses that could be bunched up over a a time period of 10 - 15 years."

Earthquake Clustering White Paper



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Global Earthquake Clustering

View EQECAT's Post Event Report - Global Earthquake Clustering

Apparent global clustering of damaging earthquakes is raising concern that our planet might experience even more catastrophic tremblors in the near future. EQECAT experts have been studying these events and have published their insights and perspectives.

Read EQECAT's expert insights into global earthquake clustering.

Japan Earthquake Digest

View EQECAT's Post Event Reports - Japan Earthquake Digest

View EQECAT's digest related to earthquakes in Japan during March 2011, including post-event reports, insights, and related CatWatch Reports, and news coverage regarding the Japan earthquake and tsunami of March 22, 2011.