Overview
- A magnitude 7.4 earthquake struck near Ciudad Hidalgo, Chiapas on July 17, and by July 26 Mexico’s Servicio Sismológico Nacional had recorded 1,003 aftershocks with the largest reaching magnitude 6.5.
- New moderate quakes updated the Chiapas sequence with a M5.9 recorded late on July 27 and several 4.x events on July 28, and authorities have not reported major new structural damage from those recent shocks.
- The SSN is issuing routine seismic bulletins and advising inspections of buildings and preparedness measures as it tracks ongoing activity on the Cocos plate subduction margin off southern Mexico.
- A separate magnitude 7.1 earthquake struck Kumamoto in Kyushu on July 28, prompting JMA tsunami alerts and leaving at least 50 people injured, partial collapse at a shopping mall, multiple fires, tens of thousands without power, and suspended rail services including the Shinkansen.
- The events show two different risks from the Pacific Ring of Fire: a prolonged aftershock sequence that requires long-term monitoring and local inspections in Mexico, and a single damaging mainshock in Japan that has immediate rescue, infrastructure repair and power-restoration needs.