M4.2 Earthquake 168 km ESE of San Jose Village, Northern Mariana Islands — October 16, 2021
2021-10-16 20:07:08 UTC (2021-10-16) · approx. 6:07 AM UTC+10 local
On October 16, 2021 at 20:07 UTC, a magnitude 4.2 shallow crustal earthquake struck 168 km ESE of San Jose Village, Northern Mariana Islands, at a depth of 10.0 km and coordinates 14.1534°, 146.9409°.
Physical scale: An earthquake of magnitude 4.2 releases seismic energy equivalent to roughly 30 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 476 m — 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 3 days ago 172 km ESE of Saipan, Northern Mariana Islands. 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
146.9409°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.2 earthquake near San Jose Village, Northern Mariana Islands?
The magnitude 4.2 earthquake that struck 168 km ESE of San Jose Village, Northern Mariana Islands on October 16, 2021 at 20:07 UTC had a depth of 10.0 km. For context, this was a light earthquake commonly felt near the epicenter.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.2 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 4.2 earthquake is an aftershock of the larger magnitude 5.1 mainshock that occurred earlier 172 km ESE of Saipan, Northern Mariana Islands. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
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Understanding This Data
Magnitude 4.2 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us6000fw74). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, October 16, 2021). M4.2 Earthquake 168 km ESE of San Jose Village, Northern Mariana Islands — October 16, 2021. Retrieved December 25, 2021 from https://www.earthquaketracker.org/earthquakes/event/us6000fw74/