The Sendai Earthquake epicenter of the earthquake late afternoon at around 2:46 P.M. at the Pacific Ocean by the undersea Trench of Japan about 80 miles (129 km) from Sendai, Japan was strong and surprised most because the plate boundary was not linear. The cause for this strong earthquake from my memories in earth science school is a deep subduction zone earthquake. There are large strain on the rocks along, where the Pacific Plate subducted underneath Okhotsk Plate where Japan is on at the accreationary wedge. There is strain in rocks at this region, because several plates boundaries are near Northern Japan islands. These plates are the Eurasia, Pacific, Okhotsk, and the debate able Amurian or China Plate. The Japan trench is an undersea geomorphology feature from the Pacific Plate subducting underneath Japan and Okhotsk Plate. Northern Japan is on the Okhotsk Plate.
http://www.jma.go.jp/en/quake/20110311145338384-111446.htmlhttp://en.wikipedia.org/wiki/File:Okhotsk_Plate_map_en.pnghttp://en.wikipedia.org/wiki/Amurian_PlateThe Pacific Northwest in the U.S.A. like Portland and Seattle areas are in hazard of this type of strong earthquake by the Juan de Fuca Plate subducted underneath the North America Plate. California's earthquakes are different, linear strike slip, right lateral fault with horizontal northwest trending motion about a cm per year. California has a part that does not belong to the North American Plate, that is Santa Cruz. Geologically, that part of California is not part of the state. Politically and economically Santa Cruz is part of California. Socially, it is not. Look at the banners that I seen years ago, "President Bush's Policies are Terrorist." There are sofas outside for people to sit and fall in love. Stockton is more conservative. We named an elementary school after, George W. Bush, Jr. The one who got shoes thrown at him.
Tsunami has arrived in California around 7:45 A.M. Not much damage according to the news, a few boats smashed against the docks.
http://www.jma.go.jp/en/quake/ Subduction zone earthquakes are the strongests and the energy radiated out to the Western Pacific Ocean side with tsunamis.
Lawsen