M4.0 Earthquake 139 km N of Lae, Papua New Guinea — September 27, 2023
2023-09-27 23:58:47 UTC (2023-09-27) · approx. 9:58 AM UTC+10 local
On September 27, 2023 at 23:58 UTC, a magnitude 4.0 intermediate depth earthquake struck 139 km N of Lae, Papua New Guinea, at a depth of 178.4 km and coordinates -5.4639°, 147.0735°.
Physical scale: An earthquake of magnitude 4.0 releases seismic energy equivalent to roughly 15 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 347 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 5.5 mainshock that occurred 7 days ago 116 km ESE of Madang, Papua New Guinea. 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.
Earthquake Details
147.0735°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.0 earthquake near Lae, Papua New Guinea?
The magnitude 4.0 earthquake that struck 139 km N of Lae, Papua New Guinea on September 27, 2023 at 23:58 UTC had a depth of 178.4 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 4.0 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 4.0 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.
Actions
Understanding This Data
Magnitude 4.0 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us6000lcgd). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, September 27, 2023). M4.0 Earthquake 139 km N of Lae, Papua New Guinea — September 27, 2023. Retrieved December 9, 2023 from https://www.earthquaketracker.org/earthquakes/event/us6000lcgd/