4.2

M4.2 Earthquake 180 km E of Kokopo, Papua New GuineaDecember 6, 2021

2021-12-06 17:43:48 UTC (2021-12-06) · approx. 3:43 AM UTC+10 local

MagnitudeM4.2(mb)
Time17:43 UTC3:43 AM UTC+10
Depth303.2 kmdeep-focus
Coordinates-4.210°, 153.886°
Felt byNo felt reports
Status✓ Reviewed by USGS

On December 6, 2021 at 17:43 UTC, a magnitude 4.2 deep-focus earthquake struck 180 km E of Kokopo, Papua New Guinea, at a depth of 303.2 km and coordinates -4.2098°, 153.8860°.

Physical scale: An earthquake of magnitude 4.2 releases seismic energy equivalent to roughly 30 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 476 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 12 days ago 162 km E of Kokopo, 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 -4.21°, 153.89°

Earthquake Details

Magnitude
4.2 mb
Depth
303.2 km
deep-focus
Location
-4.2098°N
153.8860°E

Technical Information

Event ID
us6000gb5w
Event Type
earthquake
Status
✓ Reviewed
Significance
271
Azimuthal Gap
125.0°
Min Station Distance
1.717°
RMS Residual
1.32 sec
Last Updated
2022-02-12 23:07:27 UTC

Common Questions

How strong was the magnitude 4.2 earthquake near Kokopo, Papua New Guinea?

The magnitude 4.2 earthquake that struck 180 km E of Kokopo, Papua New Guinea on December 6, 2021 at 17:43 UTC had a depth of 303.2 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 4.2 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 4.2 earthquake is an aftershock of the larger magnitude 5.5 mainshock that occurred earlier 162 km E of Kokopo, Papua New Guinea. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.

Understanding This Data

Magnitude 4.2 earthquakes are often felt but rarely cause damage.

Learn more about magnitude →

Authoritative source: USGS event page (event ID: us6000gb5w). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2021, December 6, 2021). M4.2 Earthquake 180 km E of Kokopo, Papua New GuineaDecember 6, 2021. Retrieved February 12, 2022 from https://www.earthquaketracker.org/earthquakes/event/us6000gb5w/