M4.5 Earthquake 15 km S of Calatagan, Philippines — June 23, 2023
2023-06-23 19:12:00 UTC (2023-06-23) · approx. 3:12 AM UTC+8 local
Aftershock of the M5.0 mainshock.
On June 23, 2023 at 19:12 UTC, a magnitude 4.5 intermediate depth earthquake struck 15 km S of Calatagan, Philippines, at a depth of 148.5 km and coordinates 13.6877°, 120.6296°. This earthquake was detected by 102 seismic stations with good location accuracy and was assigned a USGS significance rating of 312, placing it among routine seismic activity.
Physical scale: An earthquake of magnitude 4.5 releases seismic energy equivalent to roughly 85 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 767 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 5.0 mainshock that occurred 21 days ago 7 km NW of Cabacao, Philippines. Since the mainshock, the USGS has recorded 0 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
120.6296°E
Technical Information
Common Questions
How strong was the magnitude 4.5 earthquake near Calatagan, Philippines?
The magnitude 4.5 earthquake that struck 15 km S of Calatagan, Philippines on June 23, 2023 at 19:12 UTC had a depth of 148.5 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at 13.6877°, 120.6296°, which is 15 km S of Calatagan, Philippines. View all earthquakes in Philippines.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.5 earthquakes can continue for several days and gradually diminish over time.
Is this the same earthquake as the M5.0 one earlier?
No. This magnitude 4.5 earthquake is an aftershock of the larger magnitude 5.0 mainshock that occurred earlier 7 km NW of Cabacao, 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 4.5 event is significantly smaller than that historical record.
Authoritative source: USGS event page (event ID: us7000kapj). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, June 23, 2023). M4.5 Earthquake 15 km S of Calatagan, Philippines — June 23, 2023. Retrieved August 26, 2023 from https://www.earthquaketracker.org/earthquakes/event/us7000kapj/