M4.9 Earthquake 78 km NE of Simao, China — July 21, 2026
2026-07-21 11:43:08 UTC (2 hours ago) · approx. 6:43 PM UTC+7 local
On July 21, 2026 at 11:43 UTC, a magnitude 4.9 shallow crustal earthquake struck 78 km NE of Simao, China, at a depth of 10.0 km and coordinates 23.2707°, 101.5395°. This earthquake was detected by 63 seismic stations with excellent location accuracy and was assigned a USGS significance rating of 369, placing it among routine seismic activity.
Physical scale: An earthquake of magnitude 4.9 releases seismic energy equivalent to roughly 338 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 1.4 km — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
101.5395°E
Technical Information
Common Questions
How strong was the magnitude 4.9 earthquake near Simao, China?
The magnitude 4.9 earthquake that struck 78 km NE of Simao, China on July 21, 2026 at 11:43 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 23.2707°, 101.5395°, which is 78 km NE of Simao, China.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.9 earthquakes can continue for several days and gradually diminish over time.
Actions
Location
Authoritative source: USGS event page (event ID: us7000t25s). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2026, July 21, 2026). M4.9 Earthquake 78 km NE of Simao, China — July 21, 2026. Retrieved July 21, 2026 from https://www.earthquaketracker.org/earthquakes/event/us7000t25s/