Revision History

Two magnitude-5 earthquakes struck northern Nagano Prefecture on April 18, 2026, temporarily suspending Hokuriku Shinkansen service and registering upper-5 shaking intensity in Omachi — strong enough to make walking difficult — yet producing no confirmed casualties or structural collapses. The event highlights both the effectiveness of Japan's post-1995 building code reforms and lingering questions about preparedness in rural, mountainous communities sitting atop the high-risk Itoigawa-Shizuoka Tectonic Line.