M4.3 Earthquake 138 km SSW of Hihifo, Tonga — August 19, 2021
2021-08-19 20:21:15 UTC (2021-08-19) · approx. 8:21 AM UTC-12 local
On August 19, 2021 at 20:21 UTC, a magnitude 4.3 intermediate depth earthquake struck 138 km SSW of Hihifo, Tonga, at a depth of 109.7 km and coordinates -17.1336°, -174.2393°.
Physical scale: An earthquake of magnitude 4.3 releases seismic energy equivalent to roughly 43 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 558 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
-174.2393°E
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Common Questions
How strong was the magnitude 4.3 earthquake near Hihifo, Tonga?
The magnitude 4.3 earthquake that struck 138 km SSW of Hihifo, Tonga on August 19, 2021 at 20:21 UTC had a depth of 109.7 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 4.3 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 4.3 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us7000f5sf). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, August 19, 2021). M4.3 Earthquake 138 km SSW of Hihifo, Tonga — August 19, 2021. Retrieved October 29, 2021 from https://www.earthquaketracker.org/earthquakes/event/us7000f5sf/