M4.9 Earthquake southeast of the Loyalty Islands — September 29, 2021
2021-09-29 17:05:54 UTC (2021-09-29) · approx. 4:05 AM UTC+11 local
On September 29, 2021 at 17:05 UTC, a magnitude 4.9 shallow crustal earthquake struck southeast of the Loyalty Islands, at a depth of 10.0 km and coordinates -22.8258°, 171.7090°.
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.
Earthquake Details
171.7090°E
Technical Information
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Common Questions
How strong was the magnitude 4.9 earthquake southeast of the Loyalty Islands?
The magnitude 4.9 earthquake that struck southeast of the Loyalty Islands on September 29, 2021 at 17:05 UTC had a depth of 10.0 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at -22.8258°, 171.7090°, which is southeast of the Loyalty Islands.
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.
Actions
Authoritative source: USGS event page (event ID: us6000fq75). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, September 29, 2021). M4.9 Earthquake southeast of the Loyalty Islands — September 29, 2021. Retrieved December 22, 2025 from https://www.earthquaketracker.org/earthquakes/event/us6000fq75/