M4.8 Earthquake in the Mariana Islands region — October 20, 2021
2021-10-20 03:28:33 UTC (2021-10-20) · approx. 1:28 PM UTC+10 local
On October 20, 2021 at 03:28 UTC, a magnitude 4.8 intermediate depth earthquake struck in the Mariana Islands region, at a depth of 81.1 km and coordinates 21.8559°, 144.4391°.
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
144.4391°E
Technical Information
Common Questions
How strong was the magnitude 4.8 earthquake in the Mariana Islands region?
The magnitude 4.8 earthquake that struck in the Mariana Islands region on October 20, 2021 at 03:28 UTC had a depth of 81.1 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at 21.8559°, 144.4391°, which is in the Mariana Islands region.
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: us6000fw12). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, October 20, 2021). M4.8 Earthquake in the Mariana Islands region — October 20, 2021. Retrieved December 25, 2021 from https://www.earthquaketracker.org/earthquakes/event/us6000fw12/