Tokyo: A new study is warning that the Tokyo
region has a 70 per cent chance of being hit directly by a
powerful magnitude-7 earthquake within four years.
The study by University of Tokyo seismologists bases the
estimate on an increase in earthquake activity in the Tokyo
region since last year's March 11 disaster, when a magnitude-9
quake and subsequent tsunami about 230 kilometres northeast of
the capital left nearly 20,000 people dead or missing.
The group at the university's earthquake research
institute said the number of moderate quakes in the capital
region measuring magnitude 3 or bigger surged to 343 in the
six-month period after the March quake, up from 47 in the
previous six months.
Based on a theory that the probability of bigger
earthquakes rises in proportion to an increase in smaller
quakes, the team calculated a 98 per cent likelihood of a
magnitude 6.7 to 7.2 earthquake striking Tokyo over the next
30 years.
Stated differently, "When we ask when a probability of
such a quake reaches 70 per cent, then we get a 70 per cent
chance over the next four years," said Shinichi Sakai, a
seismologist on the team.
A separate government study estimates that the chance of
a magnitude-7 quake striking Tokyo is 70 per cent over the
next 30 years.
PTI
First Published: Tuesday, January 24, 2012, 18:25