A study by global reinsurance broker Guy Carpenter challenges accepted views on seismic risk.
The market’s understanding of seismic risk changed after the Tohoku rupture of 2011. The seismic event was significantly more powerful than anything that was thought possible by scientists. Following the event there was increased publicity surrounding the Tokyo Fragment theory and discussion around the potentially increased probability of earthquakes near Tokyo.
Guy Carpenter is sponsoring a review of the available research literature by professor Paul Somerville of Risk Frontiers to bring objective balance to the discussion surrounding Japan earthquake risk following the 2011 rupture.
James Nash, CEO for the Asia Pacific region at Guy Carpenter, said: “The integration of scientific research in a balanced way is critical to our understanding of risk and the risk management decisions faced by insurance companies as they evaluate the risk and reward trade off.”
While there is general agreement among scientists that stress increases near Tokyo have occurred, preliminary research suggests that there are divergent theories regarding how this increase in stress influences earthquake risk in Tokyo.
Computations performed by Toda and Stein of the US Geological Survey suggest long-term increases in risk by a factor of x2.5. Uchida and Matsuzawa of the Research Center for Prediction of Earthquakes and Volcanic Eruptions contest this view. They suggest that the stress increase caused by the Tohoku earthquake is being released aseismically, and thus does not increase long-term risk near Tokyo.
