M4.3 Earthquake 147 km E of Masamba, Indonesia — December 20, 2025
2025-12-20 22:59:23 UTC (2025-12-20) · approx. 6:59 AM UTC+8 local
On December 20, 2025 at 22:59 UTC, a magnitude 4.3 shallow crustal earthquake struck 147 km E of Masamba, Indonesia, at a depth of 10.0 km and coordinates -2.5180°, 121.6537°.
Physical scale: An earthquake of magnitude 4.3 releases seismic energy equivalent to roughly 43 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 558 m — a useful intuition for the size of the slip patch on the fault.
Did You Feel It? — community-reported shaking
Aggregated felt-report intensity from 1 citizen response to the USGS Did You Feel It? system. Each colored zone represents the average MMI from reports in that area.
Source: U.S. Geological Survey Did You Feel It?. View on USGS · submit your own report
Earthquake Details
121.6537°E
Technical Information
Common Questions
How strong was the magnitude 4.3 earthquake near Masamba, Indonesia?
The magnitude 4.3 earthquake that struck 147 km E of Masamba, Indonesia on December 20, 2025 at 22:59 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 4.3 earthquakes can continue for several days and gradually diminish over time.
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.
Actions
Understanding This Data
Magnitude 4.3 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us6000rw8t). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, December 20, 2025). M4.3 Earthquake 147 km E of Masamba, Indonesia — December 20, 2025. Retrieved May 23, 2026 from https://www.earthquaketracker.org/earthquakes/event/us6000rw8t/