The seismicity of the Sanriku coast identifies and describes the seismic activity of an area of Japan. Seismicity refers to the frequency, type and size of earthquakes experienced over a period of time. The is a descriptive term referring to the coastal areas of the former provinces of Rikuō in Aomori, Rikuchū in Aomori, and Rikuzen in Miyagi. The irregular ria coastline and its many bays tend to amplify the destructiveness of tsunami waves which reach the shores of Sanriku, as demonstrated in the damage caused by the 2011 Tōhoku earthquake and tsunami. History The Sanriku coast has a well-documented history of significant seismic activity. A major earthquake in the 19th century caused more than 20,000 deaths, and another in the 20th century caused thousands more. The recurrence of major seismic activity continues in the 21st century. Ancient There is geological evidence, uncovered after the latest tsunami event of 2011, of six catastrophic tsunamis hitting the Sanriku coast within 6000 years. Among them are: A catastrophic tsunami about 5400–6000 years ago, predating the Towada eruption. A catastrophic tsunami about 2000 years ago. 869 AD, Jogan earthquake and tsunami. 1611 AD, Keicho Sanriku earthquake. 19th century Some 22,000 people were killed in the Meiji Sanriku earthquake of 1896. Most of the deaths were caused by tsunami. The disaster struck at 7:32pm on the afternoon of June 15. The epicenter was determined to have been located at 39.5 Latitude/140.6 Longitude, but no Richter Scale magnitude can be assessed on the basis of available data. 20th century Major seismic activity on the Sanriku coast during the 20th century includes: 1933 Sanriku earthquake- More than 3,000 people died; the casualties were caused by the subsequent tsunami. This quake/tsunami was not on the scale of the March 2011 disaster, nor earlier disasters noted above. 1978 Miyagi earthquake. Damage was greatest around Sendai. The earthquake triggered widespread landslides. 1994 offshore Sanriku earthquake. Damage in Hachinohe, Aomori. 21st century Significant seismic events which devastated Sanriku coastal communities in the 21st century include: 2003 Miyagi earthquake. There were two major earthquakes in 2003 in Miyagi Prefecture. The first quake in May injured 171 and caused $97.3 million in damages. Another quake in July injured 676. More than 11,000 buildings were affected, causing an estimated $195.4 million in damages. 2005 Miyagi earthquake. The seismic event was originally recorded by the United States Geological Survey as a 7.2-magnitude earthquake on