One of the most powerful earthquakes on record in Japan A massive earthquake with a magnitude of 9.0
A massive earthquake with a moment magnitude (M) of 9.0 struck off the Sanriku Coast.
Seismic intensities of level 6+ on the Japanese seismic scale were recorded in 37 municipalities in 4 prefectures, including Miyagi Prefecture. Tremors with seismic intensities of levels 1 to 6– on the Japanese scale were felt through almost all parts of the Japanese archipelago. A maximum seismic intensity of level 7 on the same scale was registered in the city of Kurihara in Miyagi Prefecture. This massive earthquake was one of the most powerful on record in Japan.
This earthquake is known as the 2011 off the Pacific Coast of Tohoku Earthquake, while the associated disasters are collectively referred to as the Great East Japan Earthquake.
The fourth largest earthquake in the world
This world map shows hypocenters for massive earthquakes of a magnitude of 8.5 or greater that have occurred around the world since 1900. As can be seen, major earthquakes occur in the regions that surround the Pacific Ocean. As of 2020, the 2011 off the Pacific Coast of Tohoku Earthquake was the fourth largest earthquake in the world.
254 aftershocks of magnitude 5.0 or greater in a day
A major characteristic of this earthquake is that, during the first shock, the tremors continued for a long time. The city of Sendai in Miyagi Prefecture recorded a seismic intensity level 4 or greater on the Japanese scale for nearly three minutes. In the 24 hours after the main shock, 46 aftershocks of a magnitude of 6.0 or greater, and 254 aftershocks with a magnitude of 5.0 or greater were felt. Six aftershocks of a magnitude of 7.0 or above occurred during the six months that followed.
The Oshika Peninsula of Miyagi Prefecture shifted more than five meters
It is evident that the land shifted a significant amount, eastward over a wide area of eastern Japan and downward along the Pacific coast of the Tohoku region.
The largest shift occurred on the Oshika Peninsula in Ishinomaki City, Miyagi Prefecture. The land here shifted horizontally about 5.3 meters toward the epicenter—in other words, toward the east-southeast—and also sank about 1.2 meters. The Sea of Japan-side of the country shifted horizontally about one meter, meaning that the whole of eastern Japan was stretched dramatically along its east–west axis. This is illustrative of the immense power possessed by this earthquake.
