Pacific Northwest Faces Tsunami Risk

摘要

For the U.S., the clear danger from a tsunami lies just offshore in the Pacific seabed where the Cascadia Subduction Zone shows up as a fault stretching about 800 miles, from Vancouver Island to Punta Gorda, Calif. Seismologists say it has the potential to do almost exactly what happened on March 11 off Japan's northeastern coast: generate a giant earthquake and tsunami that would hit the coast in minutes. Subduction-zone faults can abruptly shift seabed elevation, which spawns a tsunami. Long faults that break all at once-such as the 1,600-kilometer-long fault that caused the Indonesian tsunami in December 2004-pose the greatest risk.