A strong earthquake measuring upper-5 on Japan's seismic intensity scale struck northern Nagano Prefecture (a mountainous inland region in central Honshu) on the afternoon of the 18th, with the city of Omachi recording the peak intensity. No tsunami warning was issued. As a precaution, the Tateyama Kurobe Alpine Route — a popular mountain tourism corridor linking Omachi in Nagano with Tateyama in Toyama Prefecture — suspended cable car, ropeway, and electric bus services between Kurobe Lake and Murodo to allow for safety checks.