4.0

M4.0 Earthquake 20 km NE of Finschhafen, Papua New GuineaJune 28, 2025

2025-06-28 19:24:31 UTC (2025-06-28) · approx. 5:24 AM UTC+10 local

MagnitudeM4.0(mb)
Time19:24 UTC5:24 AM UTC+10
Depth48.7 kmshallow crustal
Coordinates-6.440°, 147.988°
Felt byNo felt reports
Status✓ Reviewed by USGS

On June 28, 2025 at 19:24 UTC, a magnitude 4.0 shallow crustal earthquake struck 20 km NE of Finschhafen, Papua New Guinea, at a depth of 48.7 km and coordinates -6.4400°, 147.9885°.

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 5.1 mainshock that occurred 27 days ago 21 km NW of Finschhafen, 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.

Map showing earthquake epicenter at -6.44°, 147.99°

Earthquake Details

Magnitude
4.0 mb
Depth
48.7 km
shallow crustal
Location
-6.4400°N
147.9885°E

Technical Information

Event ID
us7000qblk
Event Type
earthquake
Status
✓ Reviewed
Significance
246
Stations Used
16
Azimuthal Gap
118.0°
Min Station Distance
3.058°
RMS Residual
0.58 sec
Last Updated
2025-09-04 20:40:06 UTC

Common Questions

How strong was the magnitude 4.0 earthquake near Finschhafen, Papua New Guinea?

The magnitude 4.0 earthquake that struck 20 km NE of Finschhafen, Papua New Guinea on June 28, 2025 at 19:24 UTC had a depth of 48.7 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 M5.1 one earlier?

No. This magnitude 4.0 earthquake is an aftershock of the larger magnitude 5.1 mainshock that occurred earlier 21 km NW of Finschhafen, Papua New Guinea. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.

Understanding This Data

Magnitude 4.0 earthquakes are often felt but rarely cause damage.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: us7000qblk). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2025, June 28, 2025). M4.0 Earthquake 20 km NE of Finschhafen, Papua New GuineaJune 28, 2025. Retrieved September 4, 2025 from https://www.earthquaketracker.org/earthquakes/event/us7000qblk/