At the time of the 2011 Tohoku earthquake, the
tsunami warning issued in 3 minutes of the
earthquake saved many lives yet resulted in 18,500
casualties. The long-term earthquake forecast made
before 2011 estimated the 30 year probability of 99
% in the source region with smaller (M~ 8) size.
The source of the 2011 earthquake was modeled as
a combination of the 1896 “tsunami earthquake” and
the 869 Jogan earthquake.