Summary of the seismographic observation of the Matsushiro swarm earthquakes



The Matsushiro swarm earthquakes commenced in August 1965 and continued for more than three years. The Earthquake Research Institute, University of Tokyo, conducted tripartite observation using very sensitive seismographs in four places in the active area in parallel with an ordinary seismographic network set up in that area. The observation was continued throughout the entire period of activity. An outline of the activity of the earthquakes will first be reported