M4.8 Earthquake west of Macquarie Island — August 13, 2023
2023-08-13 01:10:03 UTC (2023-08-13) · approx. 11:10 AM UTC+10 local
Aftershock of the M5.1 mainshock.
On August 13, 2023 at 01:10 UTC, a magnitude 4.8 shallow crustal earthquake struck west of Macquarie Island, at a depth of 10.0 km and coordinates -56.5086°, 147.2782°. This earthquake was detected by 36 seismic stations with excellent location accuracy and was assigned a USGS significance rating of 354, placing it among routine seismic activity.
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.
This earthquake is part of an ongoing aftershock sequence following the magnitude 5.1 mainshock that occurred 13 days ago west of Macquarie Island. 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.
Earthquake Details
147.2782°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 August 13, 2023 at 01:10 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 -56.5086°, 147.2782°, 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.
Is this the same earthquake as the M5.1 one earlier?
No. This magnitude 4.8 earthquake is an aftershock of the larger magnitude 5.1 mainshock that occurred earlier west of Macquarie Island. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
Actions
Authoritative source: USGS event page (event ID: us6000kzmj). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, August 13, 2023). M4.8 Earthquake west of Macquarie Island — August 13, 2023. Retrieved October 27, 2023 from https://www.earthquaketracker.org/earthquakes/event/us6000kzmj/