A magnitude 5.0 earthquake struck northern Nagano Prefecture on the afternoon of Saturday, April 18, triggering a series of subsequent tremors that have left the region on high alert. The initial quake, occurring around 1:20 PM, produced a maximum intensity of 5-upper in Omachi City and 5-lower in Nagano City.
Ongoing Seismic Risks and Warnings
The Japan Meteorological Agency (JMA) has advised residents to remain vigilant for approximately one week. This warning stems from historical precedents where earthquakes of similar scales have occurred consecutively in this specific region.
Authorities warn that further tremors of intensity 5-upper could occur and there is a possibility of even stronger earthquakes. Residents are urged to ensure furniture is secured and emergency supplies are verified.
Weather Forecast: Impending Rain and Landslide Threats
Weather patterns are expected to shift quickly, with rain forecast for Tuesday, April 21. A front passing through North and East Japan may bring intense bursts of rain to Nagano during the morning commute and school hours, though conditions are likely to recover rapidly by the afternoon.
Further substantial rain is expected between Thursday, April 23, and Friday, April 24, across West and East Japan, including Nagano Prefecture.
Due to the loosened soil in areas that experienced strong shaking, the JMA has implemented provisional standards for heavy rain warnings and advisories. By lowering the soil rain amount index criteria, authorities intend to provide earlier warnings for landslide risks, which are now higher than usual.
Emergency Response Guidelines
To ensure safety during sudden tremors or emergency alerts, the following protocols are recommended:
- At Home: Protect your head and seek shelter under sturdy furniture. Avoid rushing outside or attempting to extinguish fires immediately; instead, secure an exit route by opening doors.
- In Elevators: Stop at the nearest floor and exit immediately.
- In Public: Be cautious of collapsing block walls, falling signs, and breaking glass. Seek shelter inside sturdy buildings.
- While Driving: Avoid abrupt braking. Slow down gradually, activate hazard lights, and pull over to the left side of the road if strong shaking is felt.
- Near Mountains: Remain alert for falling rocks and landslides.
Frequently Asked Questions
What was the maximum intensity recorded during the April 18 earthquake?
The maximum intensity was 5-upper, which was observed in Omachi City, Nagano Prefecture.
When is the next significant rainfall expected in Nagano?
Rain is expected on Tuesday, April 21, particularly during the morning hours, with more substantial rain forecast for April 23 and 24.
Why has the JMA changed its warning criteria for rain?
Because the recent strong shaking has loosened the ground, the risk of landslides is higher than normal. The JMA has lowered the provisional standards for issuing heavy rain warnings and advisories.
Have you checked your emergency kit and secured your heavy furniture this week?
