2.4

M2.4 Earthquake 10km NNW of Anza, CAOctober 21, 2021

2021-10-21 17:22:23 UTC (2021-10-21) · approx. 9:22 AM UTC-8 local

MagnitudeM2.4(ml)
Time17:22 UTC9:22 AM UTC-8
Depth14.6 kmshallow crustal
Coordinates33.633°, -116.717°
Felt by5DYFI responses
Status✓ Reviewed by USGS

On October 21, 2021 at 17:22 UTC, a magnitude 2.4 shallow crustal earthquake struck 10km NNW of Anza, CA, at a depth of 14.6 km and coordinates 33.6335°, -116.7170°.

Physical scale: An earthquake of magnitude 2.4 releases seismic energy equivalent to roughly 62.1 kg of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 28 m — a useful intuition for the size of the slip patch on the fault.

Map showing earthquake epicenter at 33.63°, -116.72°

Did You Feel It? — community-reported shaking

Aggregated felt-report intensity from 5 citizen responses 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 M2.4 earthquake near 10km NNW of Anza, CA

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

Earthquake Details

Magnitude
2.4 ml
Depth
14.6 km
shallow crustal
Location
33.6335°N
-116.7170°E
Felt Reports
5
DYFI responses
Community Intensity
3.1
CDI from reports

Technical Information

Event ID
ci39839543
Event Type
earthquake
Status
✓ Reviewed
Significance
91
Stations Used
87
Azimuthal Gap
19.0°
Min Station Distance
0.050°
RMS Residual
0.17 sec
Last Updated
2021-10-21 19:44:05 UTC

Common Questions

How strong was the magnitude 2.4 earthquake near Anza, CA?

The magnitude 2.4 earthquake that struck 10km NNW of Anza, CA on October 21, 2021 at 17:22 UTC had a depth of 14.6 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 2.4 earthquakes can continue for several days and gradually diminish over time.

Understanding This Data

Magnitude 2.4 earthquakes are typically only recorded by instruments.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: ci39839543). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2021, October 21, 2021). M2.4 Earthquake 10km NNW of Anza, CAOctober 21, 2021. Retrieved October 21, 2021 from https://www.earthquaketracker.org/earthquakes/event/ci39839543/