2.8

M2.8 Earthquake 4km NW of Cobb, CA — May 26, 2021

2021-05-26 17:54:02 UTC (2021-05-26) · approx. 9:54 AM UTC-8 local

MagnitudeM2.8(md)
Time17:54 UTC≈ 9:54 AM UTC-8
Depth1.3 kmshallow crustal
Coordinates38.846°, -122.760°
Felt by1DYFI response
Status✓ Reviewed by USGS

On May 26, 2021 at 17:54 UTC, a magnitude 2.8 shallow crustal earthquake struck 4km NW of Cobb, CA, at a depth of 1.3 km and coordinates 38.8457°, -122.7602°.

Physical scale: An earthquake of magnitude 2.8 releases seismic energy equivalent to roughly 223 kg of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 50 m — a useful intuition for the size of the slip patch on the fault.

Map showing earthquake epicenter at 38.85°, -122.76°

Did You Feel It? — community-reported shaking

Aggregated felt-report intensity from 1 citizen response to the USGS Did You Feel It? system. Each colored zone represents the average MMI from reports in that area.

USGS DYFI community-reported intensity map for the M2.8 earthquake near 4km NW of Cobb, CA

Source: U.S. Geological Survey Did You Feel It?. View on USGS · submit your own report

Earthquake Details

Magnitude
2.8 md
Depth
1.3 km
shallow crustal
Location
38.8457°N
-122.7602°E
Felt Reports
1
DYFI responses
Community Intensity
3.4
CDI from reports

Technical Information

Event ID
nc73565651
Event Type
earthquake
Status
✓ Reviewed
Significance
119
Stations Used
72
Azimuthal Gap
38.0°
Min Station Distance
0.009°
RMS Residual
0.06 sec
Last Updated
2021-07-31 22:10:00 UTC

Common Questions

How strong was the magnitude 2.8 earthquake near Cobb, CA?

The magnitude 2.8 earthquake that struck 4km NW of Cobb, CA on May 26, 2021 at 17:54 UTC had a depth of 1.3 km. For context, this was a minor earthquake typically detected only by instruments.

Were there aftershocks?

Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 2.8 earthquakes can continue for several days and gradually diminish over time.

Understanding This Data

Magnitude 2.8 earthquakes are typically only recorded by instruments.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: nc73565651). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2021, May 26, 2021). M2.8 Earthquake 4km NW of Cobb, CA — May 26, 2021. Retrieved July 31, 2021 from https://www.earthquaketracker.org/earthquakes/event/nc73565651/