Japan Nuclear Safety: Nuclear operators must plan for multiple-fault quakes
http://ajw.asahi.com/article/0311disaster/fukushima/AJ201203290069
Japans Nuclear and Industrial Safety Agency (NISA) ordered nuclear power plant operators on March 28 to prepare for the possibility of earthquakes involving multiple active faults that would cause significantly bigger shocks than previously envisaged.
The Great East Japan Earthquake stunned seismologists because it overturned a previous assumption that no magnitude-9.0 class earthquake would hit the part of the Japan Trench facing the Tohoku region. The disaster saw the release of a huge amount of energy along its length involving several different segments of the trench.
NISA's order goes beyond that to raise the hypothetical possibility, not only of several earthquakes coinciding along an oceanic trench as happened in the Tohoku temblor, but of multiple quakes coinciding on apparently separate inland faults.
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NOW they plan for the worst case scenario. Great.