the Moment magnitude scale, but the Japan Meteorological Agency called it a magnitude 6.9 earthquake. The slippage in the seabed subduction zone was located about east-northeast of Tokyo about below the surface of the Pacific Ocean. The Japan Meteorological Agency issued a tsunami warning almost immediately; and warnings were also issued for the northwest coast of the United States 2011 Tōhoku earthquake and tsunami. In March 2011, the largest earthquake ever recorded in Japan struck off the Sanriku coast, setting off a tsunami. The 9.0-magnitude quake near Tohoku was comparable in scale to undersea seismic events near Indonesia in 2004 (3rd largest on record) and near Chile in 2010 (6th largest). It caused 15,889 deaths, 6,152 injured, and 2,609 people missing across twenty prefectures, with an estimated $235 billion in property damage. Three of the most powerful earthquakes ever recorded worldwide, including the 2011 Tōhoku quake, appear to be clustered in a 6.2-year span between 2004 and 2011; however, experts construe this as a statistical anomaly or random chance. The phenomenon of comparably large quakes that happen on the same or neighbouring faults within months of each other—for example, the Miyagi quakes in 2003—can be explained by a sound geological mechanism. This does not fully demonstrate a relationship between events separated by longer periods and greater distances. Seismic mechanisms Earthquakes occur where the Pacific Plate meets the plate beneath northern Honshu in a subduction zone. The Pacific plate, which moves at a rate of per year, dips under Honshu's underlying plate releasing large amounts of energy. This motion pulls the upper plate down until the stress builds up enough to cause a seismic event. Quakes of large magnitudes in the Sanriku region can have a rupture length of hundreds of kilometers; and this generally requires a long, relatively straight fault surface. However, the plate boundary and subduction zone in this area is not very straight. The "epicentral region" of an earthquake is defined as an elliptical area which encompasses the location of highest felt intensity of an earthquake. This term is used for identifying the likely epicenter for earthquakes and tsunami in the history of the Sanriku coat. The hypocentral region of Sanriku coastal earthquakes can occur in locations extending from offshore Aomori Prefecture to offshore Ibaraki Prefecture. See also Sanriku earthquake (Sanriku tsunami) Seismicity in Japan 2011 Tohoku earthquake 1585 Aleutian Islands earthquake – a distant tsunami which is