Overview

• USGS data for Aug. 29 listed 22 earthquakes above magnitude 2.5 across North America and the Caribbean in the prior 24 hours, including 12 in the continental United States, with the strongest a magnitude 3.6 near Valmy, Nevada.
• A sequence of small events clustered near Valmy included several magnitude 3.2–3.6 quakes overnight, while a magnitude 5.5 struck offshore in the Aleutians west of Adak early on Aug. 29.
• On Aug. 28, USGS also recorded a magnitude 5.9 earthquake 241 kilometers west of Adak, Alaska, with no reports in the coverage of damage on land.
• Mexico’s seismic agency (SSN) logged a magnitude 4.0 quake at 00:03 on Aug. 28 northwest of Cintalapa, Chiapas at 133 km depth, which was lightly felt and caused no reported damage.
• SASMEX sirens did not activate because recent events did not meet the system’s distance-and-magnitude criteria, and authorities reiterated standard safety guidance for earthquake preparedness.