M4.9 Earthquake 99 km E of Hengchun, Taiwan — August 4, 2023
2023-08-04 12:22:12 UTC (2023-08-04) · approx. 8:22 PM UTC+8 local
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On August 4, 2023 at 12:22 UTC, a magnitude 4.9 shallow crustal earthquake struck 99 km E of Hengchun, Taiwan, at a depth of 10.0 km and coordinates 21.9278°, 121.7038°.0 This earthquake was detected by 76 seismic stations with good 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.
The epicenter is located in Taiwan, a region characterized by the collision of the Luzon volcanic arc with the Eurasian continental margin, where the Philippine Sea Plate converges at 80 mm per year. View all earthquakes in Taiwan.
Learn more: Magnitude scale · Aftershock sequences
Did You Feel It? — community-reported shaking
Aggregated felt-report intensity from submitted citizen responses to the USGS Did You Feel It? system. Each colored zone represents the average MMI from reports in that area.
Source: U.S. Geological Survey Did You Feel It?. View on USGS · submit your own report
Earthquake Details
121.7038°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.9 earthquake near Hengchun, Taiwan?
The magnitude 4.9 earthquake that struck 99 km E of Hengchun, Taiwan on August 4, 2023 at 12:22 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 21.9278°, 121.7038°, which is 99 km E of Hengchun, Taiwan. View all earthquakes in Taiwan.
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.
Has Taiwan had earthquakes this big before?
The largest recorded earthquake in Taiwan was the M7.6 Chi-Chi earthquake of September 21, 1999. Today's magnitude 4.9 event is significantly smaller than that historical record.
Authoritative source: USGS event page (event ID: us6000kxsl). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, August 4, 2023). M4.9 Earthquake 99 km E of Hengchun, Taiwan — August 4, 2023. Retrieved October 7, 2023 from https://www.earthquaketracker.org/earthquakes/event/us6000kxsl/