M4.6 Earthquake 52 km NNE of Namuac, Philippines — September 22, 2025
2025-09-22 20:33:00 UTC (2025-09-22) · approx. 4:33 AM UTC+8 local
Aftershock of the M5.3 mainshock.
On September 22, 2025 at 20:33 UTC, a magnitude 4.6 shallow crustal earthquake struck 52 km NNE of Namuac, Philippines, at a depth of 45.4 km and coordinates 19.0218°, 121.4160°. This earthquake was detected by 63 seismic stations with good location accuracy and was assigned a USGS significance rating of 326, placing it among routine seismic activity.
Physical scale: An earthquake of magnitude 4.6 releases seismic energy equivalent to roughly 120 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 899 m — a useful intuition for the size of the slip patch on the fault.
This earthquake is part of an ongoing aftershock sequence following the magnitude 5.3 mainshock that occurred 14 days ago 54 km N of Namuac, Philippines. Since the mainshock, the USGS has recorded 1 aftershocks in this area. Aftershock activity is expected to continue for days to weeks as stresses on surrounding faults redistribute.
The epicenter is located in Philippines, a region characterized by the Manila Trench and Philippine Trench subduction systems, where the Philippine Sea Plate overrides the Eurasian Plate. The nearest mapped fault system is the Philippine Fault. View all earthquakes in Philippines.
Learn more: Magnitude scale · Aftershock sequences
Earthquake Details
121.4160°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.6 earthquake near Namuac, Philippines?
The magnitude 4.6 earthquake that struck 52 km NNE of Namuac, Philippines on September 22, 2025 at 20:33 UTC had a depth of 45.4 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at 19.0218°, 121.4160°, which is 52 km NNE of Namuac, Philippines. View all earthquakes in Philippines.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.6 earthquakes can continue for several days and gradually diminish over time.
Is this the same earthquake as the M5.3 one earlier?
No. This magnitude 4.6 earthquake is an aftershock of the larger magnitude 5.3 mainshock that occurred earlier 54 km N of Namuac, Philippines. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
Has Philippines had earthquakes this big before?
The largest recorded earthquake in Philippines was the M8.0 Mindanao earthquake of August 17, 1976. Today's magnitude 4.6 event is significantly smaller than that historical record.
What should I do after an earthquake?
If you were in the affected area: check yourself and others for injuries, inspect your home for damage, and be prepared for aftershocks. For detailed guidance, see our earthquake safety guide and emergency planning resources.
Authoritative source: USGS event page (event ID: us6000rc62). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, September 22, 2025). M4.6 Earthquake 52 km NNE of Namuac, Philippines — September 22, 2025. Retrieved May 28, 2026 from https://www.earthquaketracker.org/earthquakes/event/us6000rc62/