Magnitude 5.7 Earthquake at Depth 10 km Strikes Offshore Chiapas, Mexico on 18th August 2026

A magnitude 5.7 earthquake struck offshore Chiapas, Mexico, on 18th August 2026 at 05:02 UTC, according to the United States Geological Survey (USGS). The earthquake occurred at a shallow depth of 10 km, which typically results in stronger shaking near the epicentre compared to deeper seismic events.

How Earthquake Magnitudes Are Calculated

The epicentre was located off the southern coast of Mexico, in a region known for frequent seismic activity due to the interaction between the Cocos Plate and the North American Plate. This tectonic boundary is part of the wider Middle America Trench, where the Cocos Plate subducts beneath the continental crust, generating regular moderate to strong earthquakes.

Regional Tectonic Setting

Chiapas and the surrounding offshore region sit along one of Mexico’s most active seismic zones. Subduction processes beneath the Pacific Ocean contribute to significant tectonic stress, making shallow earthquakes common. These events can be felt widely across coastal communities, even when they occur offshore.

What Is a Subduction Zone?

Shaking Characteristics and Impact

With a depth of 10 km, this earthquake is classified as shallow, meaning seismic waves reach the surface quickly and with greater intensity. Shallow quakes often produce stronger local shaking, but early reports indicated no immediate damage or injuries. No tsunami alerts were issued following the event.

How Earthquake Depth Affects Shaking, Damage, and What People Feel

Monitoring and Updates

EarthExtremities.com continues to monitor seismic activity across Mexico and the wider Pacific region. Updates will be provided if new information becomes available from USGS or regional authorities.

Why Earthquakes Happen — A Simple Explanation