The earthquake and tsunami which hit the Tohoku region of Japan last March has “changed conventional wisdom” about the probability of devastating earthquakes affecting some areas of the country.

In a newly released paper, Understanding earthquake risk in Japan following the Tohoku-Oki Earthquake, catastrophe modelling firm AIR Worldwide says that there is now a “widespread sense of urgency in re-examining the seismicity of regions neighbouring the Tohoku rupture”.

The paper says that “conventional wisdom” about quake risk in Japan had “maintained that it was not possible for such an event to occur in that segment of the Japan Trench”.

AIR Worldwide will release an updated earthquake model for Japan in mid-2013 which it says will include a “comprehensive set of enhancements”, including updated rupture probabilities and, for the first time, the impact of tsunami and liquefaction on all lines of business.

But the modeller says early indications from the quake experience have resulted in probable insured losses from earthquake in Japan increasing by an average of 15% for return periods between one and 30 years, and by about 2% for return periods between 100 and 250 years.