「History」カテゴリーアーカイブ

Day_200 : High-Speed Tsunamis and Delayed Warnings: The Urgency of Evacuation during the 1896 Meiji Sanriku, 1933 Showa Sanriku, and 2011 Great East Japan Earthquake and Tsunamis

Large tsunamis are caused by significant earthquakes of magnitude eight or greater. In particular, such earthquakes frequently occur along the Pacific coast of Hokkaido and Tohoku in Japan. The Sanriku coast in this region has a unique shape called a “rias coast,” which is prone to tsunamis. In the 1896 Meiji Sanriku tsunami, the tsunami reached a height of 38 meters and killed about 22,000 people. Thirty-seven years later, in 1933, another major tsunami, the Showa Sanriku tsunami, struck the region, killing approximately 3,000 people. 2011’s Great East Japan Earthquake and Tsunami did not fully apply the lessons of the past, leaving approximately 18,000 people dead or missing.

The time between an earthquake and a tsunami reaching the coast is very short, from 5 to 10 minutes. Running to higher ground quickly is almost the only way to protect yourself from a tsunami. The tsunami will reach the coast where it is the highest and also get to the coast the fastest. Therefore, instead of waiting for information from the outside, it is essential to have knowledge about tsunamis, understand your surroundings, and act on your judgment.

Contents (in Japanese)
Source: URL:https://dil.bosai.go.jp/workshop/2006workshop/gakusyukai21.html

Day_51 : Matsushiro Earthquake and Underground Imperial Headquarter

The Matsushiro Earthquake Research Center is located in Nagano Prefecture. It was established in 1967 by the Matsushiro Earthquake Observatory, Japan Meteorological Agency. The center’s background was based on the world’s rare earthquake swarm in the area. From 1965 to 1969, 6,780 earthquakes were observed, and they became social issues.

There are two famous stories about the establishment. The first story is that the mayor, Mr. Nakamura, declared, “We want to have science and research rather than equipment and money” after the earthquake swarm. This attracted the center. The second is that the location was the place where the planned underground imperial headquarters was just before the end of the Second World War. This explains the location, which is deep underground and has a strong structure. So this means the best location to place a seismometer.