4.4

M4.4 Earthquake 6 km E of San Fernando, PhilippinesSeptember 23, 2023

2023-09-23 22:40:37 UTC (2023-09-23) · approx. 6:40 AM UTC+8 local

MagnitudeM4.4(mb)
Time22:40 UTC6:40 AM UTC+8
Depth10.0 kmshallow crustal
Coordinates12.482°, 123.819°
Felt byNo felt reports
Status✓ Reviewed by USGS

On September 23, 2023 at 22:40 UTC, a magnitude 4.4 shallow crustal earthquake struck 6 km E of San Fernando, Philippines, at a depth of 10.0 km and coordinates 12.4820°, 123.8192°.

Physical scale: An earthquake of magnitude 4.4 releases seismic energy equivalent to roughly 60 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 655 m — a useful intuition for the size of the slip patch on the fault.

Map showing earthquake epicenter at 12.48°, 123.82°

Earthquake Details

Magnitude
4.4 mb
Depth
10.0 km
shallow crustal
Location
12.4820°N
123.8192°E

Technical Information

Event ID
us6000lbe5
Event Type
earthquake
Status
✓ Reviewed
Significance
298
Stations Used
35
Azimuthal Gap
127.0°
Min Station Distance
11.113°
RMS Residual
0.35 sec
Last Updated
2023-12-02 23:01:05 UTC

Common Questions

How strong was the magnitude 4.4 earthquake near San Fernando, Philippines?

The magnitude 4.4 earthquake that struck 6 km E of San Fernando, Philippines on September 23, 2023 at 22:40 UTC had a depth of 10.0 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 4.4 earthquakes can continue for several days and gradually diminish over time.

Understanding This Data

Magnitude 4.4 earthquakes are often felt but rarely cause damage.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: us6000lbe5). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2023, September 23, 2023). M4.4 Earthquake 6 km E of San Fernando, PhilippinesSeptember 23, 2023. Retrieved December 2, 2023 from https://www.earthquaketracker.org/earthquakes/event/us6000lbe5/