Expert: ``The underground structure is complex and prone to M5 class earthquakes.''

Regarding this earthquake, Professor Shinichi Sakai of the Earthquake Research Institute of the University of Tokyo pointed out, ``Two plates are subducting in this area, and the underground structure is complex.Earthquakes have been common in this area for a long time, and there are many cases where earthquakes of magnitude 5 occur and the subsequent activity subsides relatively quickly.'' Regarding the strong shaking that was observed in Gunma Prefecture and Saitama Prefecture, with a seismic intensity of lower 5, he said, ``The shaking was so strong that it wouldn't be surprising if landslides occurred or cracks formed on the roads.Since it's dark time, I want people to check the information released by the Japan Meteorological Agency and take the safest and brightest route possible to get home.''