M4.8 Earthquake west of Macquarie Island — December 18, 2021
2021-12-18 19:46:05 UTC (2021-12-18) · approx. 5:46 AM UTC+10 local
On December 18, 2021 at 19:46 UTC, a magnitude 4.8 shallow crustal earthquake struck west of Macquarie Island, at a depth of 10.0 km and coordinates -57.2676°, 147.4714°.
Physical scale: An earthquake of magnitude 4.8 releases seismic energy equivalent to roughly 239 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 1.2 km — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
147.4714°E
Technical Information
Common Questions
How strong was the magnitude 4.8 earthquake west of Macquarie Island?
The magnitude 4.8 earthquake that struck west of Macquarie Island on December 18, 2021 at 19:46 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 -57.2676°, 147.4714°, which is west of Macquarie Island.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.8 earthquakes can continue for several days and gradually diminish over time.
Actions
Authoritative source: USGS event page (event ID: us6000gekg). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, December 18, 2021). M4.8 Earthquake west of Macquarie Island — December 18, 2021. Retrieved December 22, 2025 from https://www.earthquaketracker.org/earthquakes/event/us6000gekg/