A government panel has said that it now thinks a huge earthquake will occur along the Nankai Trough with a probability of 60% to 94.5% or higher within the next 30 years.
In a report issued Friday, the Earthquake Research Committee widened the probability range for a magnitude 8 to 9 earthquake occurring off the country¡¯s Pacific coast from ¡°around 80%¡± it had previously announced. The change was due to unreliabilities in the past ground uplift data from Muroto Port in Kochi Prefecture and nonconstant plate strain accumulation.
¡°An actual earthquake is an unpredictable natural phenomenon,¡± said Naoshi Hirata, honorary professor at the University of Tokyo and head of the panel. ¡°We can¡¯t clearly say when it will happen. It may be more than 30 years away but may come within a year.¡±
Megaquakes have occurred along the Nankai Trough once every 90 to 150 years. The last one, with an estimated magnitude of 8, happened in 1946.
The long-term earthquake risk assessment report also showed a separately calculated 20-50% probability range.
Although it cannot be scientifically determined which assessment is superior, the panel said, ¡°the higher chances of a Nankai Trough quake should be highlighted¡± to raise local residents¡¯ awareness of an imminent disaster.
In March, the government said in its new estimate that if a magnitude 9 earthquake occurs along the trough, up to around 298,000 people would die and the country¡¯s economic loss would amount to ?292 trillion.
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