M3.9 Earthquake 136 km N of Saipan, Northern Mariana Islands — December 6, 2021
2021-12-06 18:55:19 UTC (2021-12-06) · approx. 4:55 AM UTC+10 local
On December 6, 2021 at 18:55 UTC, a magnitude 3.9 deep-focus earthquake struck 136 km N of Saipan, Northern Mariana Islands, at a depth of 520.3 km and coordinates 16.4479°, 145.7845°.
Physical scale: An earthquake of magnitude 3.9 releases seismic energy equivalent to roughly 11 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 296 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
145.7845°E
Technical Information
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Common Questions
How strong was the magnitude 3.9 earthquake near Saipan, Northern Mariana Islands?
The magnitude 3.9 earthquake that struck 136 km N of Saipan, Northern Mariana Islands on December 6, 2021 at 18:55 UTC had a depth of 520.3 km. For context, this was a minor earthquake typically detected only by instruments.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 3.9 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 3.9 earthquakes are typically only recorded by instruments.
Authoritative source: USGS event page (event ID: us6000gb5y). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, December 6, 2021). M3.9 Earthquake 136 km N of Saipan, Northern Mariana Islands — December 6, 2021. Retrieved February 12, 2022 from https://www.earthquaketracker.org/earthquakes/event/us6000gb5y/