M4.9 Earthquake northwest of Australia — September 21, 2025
2025-09-21 07:34:47 UTC (2025-09-21) · approx. 3:34 PM UTC+8 local
On September 21, 2025 at 07:34 UTC, a magnitude 4.9 shallow crustal earthquake struck northwest of Australia, at a depth of 10.0 km and coordinates -13.6971°, 122.3503°. This earthquake was detected by 35 seismic stations with excellent location accuracy and was assigned a USGS significance rating of 369, placing it among routine seismic activity.
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
122.3503°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.9 earthquake northwest of Australia?
The magnitude 4.9 earthquake that struck northwest of Australia on September 21, 2025 at 07:34 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 -13.6971°, 122.3503°, which is northwest of Australia.
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.
What should I do after an earthquake?
If you were in the affected area: check yourself and others for injuries, inspect your home for damage, and be prepared for aftershocks. For detailed guidance, see our earthquake safety guide and emergency planning resources.
Authoritative source: USGS event page (event ID: us7000qxnl). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, September 21, 2025). M4.9 Earthquake northwest of Australia — September 21, 2025. Retrieved May 28, 2026 from https://www.earthquaketracker.org/earthquakes/event/us7000qxnl/