M4.7 Earthquake 169 km NE of Nagqu, China — April 21, 2025
2025-04-21 01:07:50 UTC (2025-04-21) · approx. 7:07 AM UTC+6 local
Aftershock of the M7.0 mainshock.
On April 21, 2025 at 01:07 UTC, a magnitude 4.7 shallow crustal earthquake struck 169 km NE of Nagqu, China, at a depth of 10.0 km and coordinates 32.5723°, 93.3067°. This earthquake was detected by 187 seismic stations with excellent 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 7.0 mainshock that occurred 8 days ago 191 km ENE of Nagqu, China. Since the mainshock, the USGS has recorded 12 aftershocks in this area. Aftershock activity is expected to continue for months to years as stresses on surrounding faults redistribute.
Earthquake Details
93.3067°E
Technical Information
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Common Questions
How strong was the magnitude 4.7 earthquake near Nagqu, China?
The magnitude 4.7 earthquake that struck 169 km NE of Nagqu, China on April 21, 2025 at 01:07 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 32.5723°, 93.3067°, which is 169 km NE of Nagqu, China.
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 M7.0 one earlier?
No. This magnitude 4.7 earthquake is an aftershock of the larger magnitude 7.0 mainshock that occurred earlier 191 km ENE of Nagqu, China. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
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Authoritative source: USGS event page (event ID: us6000q7ge). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2025, April 21, 2025). M4.7 Earthquake 169 km NE of Nagqu, China — April 21, 2025. Retrieved June 27, 2025 from https://www.earthquaketracker.org/earthquakes/event/us6000q7ge/