Discovery from Tragedy: Taking Lessons from Japan’s Earthquake
The devastating earthquake in Japan which has been officially named the N Honshu earthquake may hold some valuable geologic information that can help anticipate similar earthquakes around the world. According to a press release from the Woods Hole Oceanographic Institution (WHOI) on March 11, 2011, the 8.9 magnitude earthquake that hit Japan holds especially relevant information pertaining to the west coast of the US and Canada.
According to Jeff McGuire, a geophysicist with WHOI, the N Honshu quake occurred on a subduction zone where the Pacific plate plunges under the Japanese islands. This subduction zone is the origin of the many tsunamis and quakes that frequently strike the islands. Mr. McGuire states that a similar subduction zone exists off the shores of the north-western coast of the United States and Canada covering the area including Northern California, Oregon, Washington and Vancouver Island. Evidence indicates that this subduction zone caused earthquakes of comparable magnitude in the past including the last one in the year 1700. According to Mr. McGuire, earthquakes of this magnitude repeat every 250 – 500 years.
According to Mr. McGuire, a small percentage of earthquakes trigger a larger one and these are called “foreshocks”. The foreshock phenomenon has been studied extensively by the WHOI. Senior Scientist Jian Lin was on a research cruise in the Southern Ocean when a 7.2 magnitude foreshock occurred on March 9, 2011 only 40 kilometers away from the epicenter of the March 11 quake. Extensive research is ongoing in both the Southern Ocean and off the Pacific Northwestern Coast of the US and Canada.