M4.9 Earthquake 90 km ENE of Kainantu, Papua New Guinea — September 29, 2025
2025-09-29 15:19:02 UTC (2025-09-29) · approx. 1:19 AM UTC+10 local
Aftershock of the M5.5 mainshock.
On September 29, 2025 at 15:19 UTC, a magnitude 4.9 intermediate depth earthquake struck 90 km ENE of Kainantu, Papua New Guinea, at a depth of 103.9 km and coordinates -5.8589°, 146.5567°. This earthquake was detected by 69 seismic stations with good location accuracy and was assigned a USGS significance rating of 369, placing it among routine seismic activity.
Physical scale: An earthquake of magnitude 4.9 releases seismic energy equivalent to roughly 338 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 1.4 km — 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 5.5 mainshock that occurred 17 days ago 116 km ESE of Madang, Papua New Guinea. 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 Papua New Guinea, a region characterized by the collision and subduction of the Pacific, Australian, and Solomon Sea plates. View all earthquakes in Papua New Guinea.
Learn more: Magnitude scale · Aftershock sequences
Earthquake Details
146.5567°E
Technical Information
Common Questions
How strong was the magnitude 4.9 earthquake near Kainantu, Papua New Guinea?
The magnitude 4.9 earthquake that struck 90 km ENE of Kainantu, Papua New Guinea on September 29, 2025 at 15:19 UTC had a depth of 103.9 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at -5.8589°, 146.5567°, which is 90 km ENE of Kainantu, Papua New Guinea. View all earthquakes in Papua New Guinea.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.9 earthquakes can continue for several days and gradually diminish over time.
Is this the same earthquake as the M5.5 one earlier?
No. This magnitude 4.9 earthquake is an aftershock of the larger magnitude 5.5 mainshock that occurred earlier 116 km ESE of Madang, Papua New Guinea. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
Has Papua New Guinea had earthquakes this big before?
The largest recorded earthquake in Papua New Guinea was the M8.0 New Britain earthquake of July 18, 1971. Today's magnitude 4.9 event is significantly smaller than that historical record.
Authoritative source: USGS event page (event ID: us6000rdku). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, September 29, 2025). M4.9 Earthquake 90 km ENE of Kainantu, Papua New Guinea — September 29, 2025. Retrieved December 11, 2025 from https://www.earthquaketracker.org/earthquakes/event/us6000rdku/