This map shows the location of the March 11 earthquake, as well as the foreshocks (dotted lines) and aftershocks (solid lines). The size of each circle represents the magnitude of the associated quake or shock. The map also includes land elevation data from NASA's Shuttle Radar Topography Mission and ocean bathymetry data from the British Oceanographic Data Center.
According to the U.S. Geological Survey (USGS), the earthquake occurred at a depth of 24.4 kilometers (15.2 miles) beneath the seafloor. The March 11 earthquake was preceded by a series of large foreshocks on March 9, including an M7.2 event. USGS reported that the earthquakes "occurred as a result of thrust faulting on or near the subduction zone interface plate boundary."
The March 11 quake sent tsunami waves rushing into the coast of Japan and rippling out across the entire Pacific basin. Crescent-shaped coasts and harbors, such as those near Sendai, can play a role in focusing the waves as they approach the shore. Also, since land elevation is low and flat along much of the Japanese coast, many areas are particularly vulnerable to tsunamis.
The Japan Meteorological Agency reported maximum tsunami heights of 4.1 meters at Kamaishi at 3:21 p.m. (06:21 UTC), 7.3 meters at 3:50 p.m. (06:50 UTC) at Soma, and 4.2 meters at 4:52 p.m. (07:52 UTC) at Oarai.
The U.S. Pacific Tsunami Warning Center (PTWC) reported a wave with maximum height of 2.79 meters (9.2 feet) at an observing station at Hanasaki, Hokkaido, at 3:57 p.m. local time (06:57 UTC). Other PTWC reports:
- 1.27 meters (4.2 feet) at 10:48 UTC at Midway Island
- 1.74 meters (5.7 feet) at 13:72 UTC at Kahului, Maui, Hawaii
- 1.41 meters (4.6 feet) at 14:09 UTC at Hilo, Hawaii
- 0.69 meters (2.3 feet) at 15:42 UTC in Vanuatu
- 1.88 meters (6.2 feet) at 16:54 UTC at Port San Luis, California
- 2.02 meters (6.6 feet) at 16:57 UTC at Crescent City, California
- Japan Meteorological Agency (2011, March 11). Latest Tsunami Information. Accessed March 11, 2011.
- Pacific Tsunami Warning Center (2011, March 11). Tsunami Messages for the Pacific Ocean. Accessed March 11, 2011.
- U.S. Geological Survey (2011, March 11). Magnitude 8.9 - Near The East Coast of Honshu, Japan. Accessed March 11, 2011.
Cassiopaean Session (5 October 1994 ):
Q: (L) We would also like to have more information on earth changes. Is the Japanese earthquake that just happened as you predicted last week, the last of the Japanese problem? {An entire session had been lost due to tape malfunction. It consisted in part of a prediction of an almost immediate Japanese earthquake which did occur exactly as predicted.}
A: No.
Q: (L) Can you give us more on that...
A: There will be activity about 8.9: 67 miles off Osaka coast; 9.7: central Tokyo.
Q: (L) Are all of these going to happen within this year?
A: No. Within 16 years.