Japan’s long-anticipated “big one” earthquake could result in nearly 300,000 deaths, 12.3 million evacuees, and $1.8 trillion in economic damage, according to a new government report.
The report, Japan’s first update in a decade, outlines a worst-case scenario involving a magnitude 9 earthquake along the 900km-long Nankai Trough, where tectonic plates intersect.
Disaster planners predict the quake and resulting tsunami would devastate much of Japan’s Pacific coastline west of Tokyo, causing widespread destruction.
A megaquake of this scale, comparable to the 2011 magnitude 9.0 disaster, would trigger massive building collapses, tsunamis, and fires.
The highest casualties and damage would occur if the quake struck on a winter evening, when people are concentrated in public transport hubs or in wooden homes vulnerable to fires.
Under these conditions, the death toll could reach 298,000, with total economic losses amounting to ¥270 trillion ($1.8 trillion), nearly half of Japan’s annual GDP.
Tsunamis are projected to be the biggest cause of fatalities, accounting for three times as many deaths as the quake and building collapses combined.
While the worst-case death toll has dropped from 330,000 in a previous estimate, better building standards and early warning systems are credited for the decline.
However, the forecasted economic damage has increased by 26% due to inflation and improved data analysis of tsunami and flood impact.
Japan, one of the world’s most seismically active regions, faces constant threats of large earthquakes, particularly in its densely populated coastal cities.
A new earthquake warning system, installed in 2017, was triggered last August by a non-destructive 7.1-magnitude quake, raising public concern.
Experts estimate an 80% chance of a magnitude 8-9 earthquake striking the Nankai Trough within the next 30 years, slightly higher than previous predictions.
More than 20 of Japan’s 47 prefectures, including Tokyo and Osaka, would be directly affected, with Shizuoka Prefecture expected to suffer the highest casualties, potentially exceeding 100,000 deaths.
