Potential dangers of strike–slip faults reexamined

Nature : Big, dangerous earthquakes can indeed occur along the Queen Charlotte fault off the coast of British Columbia, Canada. The magnitude-7.7 quake that struck in October 2012 has caused seismologists to rethink the danger posed by such strike–slip faults. Because the plate motion of such faults tends to be horizontal rather than vertical, less water is displaced and therefore there is less danger of a tsunami. However, in last year’s event, a rupture in the seafloor perpendicular to the Queen Charlotte fault resulted in the second largest earthquake ever recorded in Canada and caused sufficient seafloor uplift that tsunami warnings were issued as far away as Hawaii. Seismologist Thorne Lay of the University of California, Santa Cruz, and colleagues explore the thrust geometry involved in their paper published in Earth and Planetary Science Letters.