4.1

M4.1 Earthquake 237 km ESE of Pondaguitan, PhilippinesSeptember 21, 2021

2021-09-21 21:33:53 UTC (2021-09-21) · approx. 6:33 AM UTC+9 local

MagnitudeM4.1(mb)
Time21:33 UTC6:33 AM UTC+9
Depth10.0 kmshallow crustal
Coordinates5.324°, 128.058°
Felt byNo felt reports
Status✓ Reviewed by USGS

On September 21, 2021 at 21:33 UTC, a magnitude 4.1 shallow crustal earthquake struck 237 km ESE of Pondaguitan, Philippines, at a depth of 10.0 km and coordinates 5.3241°, 128.0581°.

Physical scale: An earthquake of magnitude 4.1 releases seismic energy equivalent to roughly 21 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 406 m — a useful intuition for the size of the slip patch on the fault.

Map showing earthquake epicenter at 5.32°, 128.06°

Earthquake Details

Magnitude
4.1 mb
Depth
10.0 km
shallow crustal
Location
5.3241°N
128.0581°E

Technical Information

Event ID
us7000fe4y
Event Type
earthquake
Status
✓ Reviewed
Significance
259
Azimuthal Gap
119.0°
Min Station Distance
3.013°
RMS Residual
0.56 sec
Last Updated
2021-12-03 15:02:04 UTC

Common Questions

How strong was the magnitude 4.1 earthquake near Pondaguitan, Philippines?

The magnitude 4.1 earthquake that struck 237 km ESE of Pondaguitan, Philippines on September 21, 2021 at 21:33 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 4.1 earthquakes can continue for several days and gradually diminish over time.

Understanding This Data

Magnitude 4.1 earthquakes are often felt but rarely cause damage.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: us7000fe4y). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2021, September 21, 2021). M4.1 Earthquake 237 km ESE of Pondaguitan, PhilippinesSeptember 21, 2021. Retrieved December 3, 2021 from https://www.earthquaketracker.org/earthquakes/event/us7000fe4y/