4.0

M4.0 Earthquake 38 km NE of Fronteras, MexicoAugust 16, 2026

2026-08-16 09:57:36 UTC (2026-08-16) · approx. 2:57 AM UTC-7 local

MagnitudeM4.0(mb)
Time09:57 UTC2:57 AM UTC-7
Depth6.9 kmshallow crustal
Coordinates31.100°, -109.236°
Felt byNo felt reports
Status✓ Reviewed by USGS· green PAGER
green Alertno significant casualties or damage expected

On August 16, 2026 at 09:57 UTC, a magnitude 4.0 shallow crustal earthquake struck 38 km NE of Fronteras, Mexico, at a depth of 6.9 km and coordinates 31.1002°, -109.2357°. The nearest populated place is Agua Prieta (population 91,029).

Physical scale: An earthquake of magnitude 4.0 releases seismic energy equivalent to roughly 15 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 347 m — a useful intuition for the size of the slip patch on the fault.

Map showing earthquake epicenter at 31.10°, -109.24°

ShakeMap — predicted shaking intensity

Modeled ground-motion intensity contoured on the Modified Mercalli scale (MMI). Computed by the USGS from the moment-tensor solution and regional ground-motion prediction equations.

USGS ShakeMap intensity contours for the M4.0 earthquake near 38 km NE of Fronteras, Mexico

Source: U.S. Geological Survey ShakeMap. View interactive ShakeMap on USGS

Population exposure (USGS PAGER)

Estimated population that experienced each level of shaking. Based on the USGS PAGER rapid impact assessment, which combines ShakeMap output with global population grids.

Shaking intensity (MMI)DescriptionPopulation exposed
MMI 3weak118,230
MMI 4light703

Earthquake Details

Magnitude
4.0 mb
Depth
6.9 km
shallow crustal
Location
31.1002°N
-109.2357°E
Intensity (MMI)
4.4
moderate

Technical Information

Event ID
usd0015e7e
Event Type
earthquake
Status
✓ Reviewed
Significance
246
Stations Used
50
Azimuthal Gap
121.0°
Min Station Distance
0.277°
RMS Residual
1.06 sec
Last Updated
2026-09-07 09:58:44 UTC

Common Questions

How strong was the magnitude 4.0 earthquake near Fronteras, Mexico?

The magnitude 4.0 earthquake that struck 38 km NE of Fronteras, Mexico on August 16, 2026 at 09:57 UTC had a depth of 6.9 km. For context, this was a light earthquake commonly felt near the epicenter.

Were there aftershocks?

Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.0 earthquakes can continue for several days and gradually diminish over time.

Understanding This Data

Magnitude 4.0 earthquakes are often felt but rarely cause damage.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: usd0015e7e). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2026, August 16, 2026). M4.0 Earthquake 38 km NE of Fronteras, MexicoAugust 16, 2026. Retrieved September 7, 2026 from https://www.earthquaketracker.org/earthquakes/event/usd0015e7e/