3.3

M3.3 Earthquake 12 km S of Ackerly, TexasSeptember 24, 2021

2021-09-24 19:28:25 UTC (2021-09-24) · approx. 12:28 PM UTC-7 local

MagnitudeM3.3(ml)
Time19:28 UTC12:28 PM UTC-7
Depth10.6 kmshallow crustal
Coordinates32.414°, -101.708°
Felt by5DYFI responses
Status✓ Reviewed by USGS

On September 24, 2021 at 19:28 UTC, a magnitude 3.3 shallow crustal earthquake struck 12 km S of Ackerly, Texas, at a depth of 10.6 km and coordinates 32.4142°, -101.7077°.

Physical scale: An earthquake of magnitude 3.3 releases seismic energy equivalent to roughly 1.3 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 114 m — a useful intuition for the size of the slip patch on the fault.

Map showing earthquake epicenter at 32.41°, -101.71°

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 M3.3 earthquake near 12 km S of Ackerly, Texas

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

Earthquake Details

Magnitude
3.3 ml
Depth
10.6 km
shallow crustal
Location
32.4142°N
-101.7077°E
Felt Reports
5
DYFI responses
Community Intensity
4.3
CDI from reports

Technical Information

Event ID
tx2021stmj
Event Type
earthquake
Status
✓ Reviewed
Significance
170
Stations Used
18
Azimuthal Gap
58.0°
Min Station Distance
0.121°
RMS Residual
0.20 sec
Last Updated
2021-12-28 03:18:57 UTC

Common Questions

How strong was the magnitude 3.3 earthquake near Ackerly, Texas?

The magnitude 3.3 earthquake that struck 12 km S of Ackerly, Texas on September 24, 2021 at 19:28 UTC had a depth of 10.6 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 3.3 earthquakes can continue for several days and gradually diminish over time.

Understanding This Data

Magnitude 3.3 earthquakes are typically only recorded by instruments.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: tx2021stmj). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2021, September 24, 2021). M3.3 Earthquake 12 km S of Ackerly, TexasSeptember 24, 2021. Retrieved December 28, 2021 from https://www.earthquaketracker.org/earthquakes/event/tx2021stmj/