M4.5 Earthquake in the Macquarie Island region — August 23, 2021
2021-08-23 18:06:53 UTC (2021-08-23) · approx. 5:06 AM UTC+11 local
On August 23, 2021 at 18:06 UTC, a magnitude 4.5 shallow crustal earthquake struck in the Macquarie Island region, at a depth of 10.0 km and coordinates -53.8820°, 159.2223°.
Physical scale: An earthquake of magnitude 4.5 releases seismic energy equivalent to roughly 85 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 767 m — a useful intuition for the size of the slip patch on the fault.

Earthquake Details
159.2223°E
Technical Information
Common Questions
How strong was the magnitude 4.5 earthquake in the Macquarie Island region?
The magnitude 4.5 earthquake that struck in the Macquarie Island region on August 23, 2021 at 18:06 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 -53.8820°, 159.2223°, which is in the Macquarie Island region.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.5 earthquakes can continue for several days and gradually diminish over time.
Actions
Authoritative source: USGS event page (event ID: us7000f737). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, August 23, 2021). M4.5 Earthquake in the Macquarie Island region — August 23, 2021. Retrieved November 2, 2021 from https://www.earthquaketracker.org/earthquakes/event/us7000f737/