By Erin Wayman
Some geologic faults suffer from a Jekyll-and-Hyde personality: Sections considered resistant to powerful earthquakes can sometimes produce enormous temblors. New research shows how a quake on one fault segment can weaken a neighboring section, allowing a once-steady segment to suddenly slip.
The findings could explain why Japan saw the devastating March 2011 Tohoku quake on the fault segment it did. Seismic hazards in many other fault zones may also need to be reassessed, scientists report online January 9 in Nature.
“For Tohoku, it’s a fairly convincing scenario,” says Kelin Wang, a geophysicist at the Geological Survey of Canada in Sidney, British Columbia. “But it’s not the only scenario.”