M4.7 Earthquake 142 km ENE of Saipan, Northern Mariana Islands — December 16, 2023
2023-12-16 20:17:00 UTC (2023-12-16) · approx. 6:17 AM UTC+10 local
Aftershock of the M5.0 mainshock.
On December 16, 2023 at 20:17 UTC, a magnitude 4.7 shallow crustal earthquake struck 142 km ENE of Saipan, Northern Mariana Islands, at a depth of 41.1 km and coordinates 15.6967°, 146.9846°. This earthquake was detected by 70 seismic stations with good location accuracy and was assigned a USGS significance rating of 340, placing it among routine seismic activity.
Physical scale: An earthquake of magnitude 4.7 releases seismic energy equivalent to roughly 169 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 1.1 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 5.0 mainshock that occurred 7 days ago 187 km ENE 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
146.9846°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.7 earthquake near Saipan, Northern Mariana Islands?
The magnitude 4.7 earthquake that struck 142 km ENE of Saipan, Northern Mariana Islands on December 16, 2023 at 20:17 UTC had a depth of 41.1 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at 15.6967°, 146.9846°, which is 142 km ENE of Saipan, Northern Mariana Islands.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.7 earthquakes can continue for several days and gradually diminish over time.
Is this the same earthquake as the M5.0 one earlier?
No. This magnitude 4.7 earthquake is an aftershock of the larger magnitude 5.0 mainshock that occurred earlier 187 km ENE of Saipan, Northern Mariana Islands. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
Actions
Authoritative source: USGS event page (event ID: us7000ljkt). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, December 16, 2023). M4.7 Earthquake 142 km ENE of Saipan, Northern Mariana Islands — December 16, 2023. Retrieved February 17, 2024 from https://www.earthquaketracker.org/earthquakes/event/us7000ljkt/