M4.7 Earthquake south of Tonga — April 15, 2021
2021-04-15 08:03:36 UTC (2021-04-15) · approx. 8:03 PM UTC-12 local
On April 15, 2021 at 08:03 UTC, a magnitude 4.7 shallow crustal earthquake struck south of Tonga, at a depth of 37.5 km and coordinates -24.3466°, -175.6569°.
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.
The epicenter is located in Tonga, a region characterized by the Tonga-Kermadec subduction zone, where the Pacific Plate descends at up to 240 mm per year — the fastest plate convergence on Earth. The nearest mapped fault system is the Tonga Trench. View all earthquakes in Tonga.
Learn more: Magnitude scale · Aftershock sequences
Earthquake Details
-175.6569°E
Technical Information
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Common Questions
How strong was the magnitude 4.7 earthquake south of Tonga?
The magnitude 4.7 earthquake that struck south of Tonga on April 15, 2021 at 08:03 UTC had a depth of 37.5 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at -24.3466°, -175.6569°, which is south of Tonga. View all earthquakes in Tonga.
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.
Has Tonga had earthquakes this big before?
The largest recorded earthquake in Tonga was the M8.1 Tonga Trench earthquake of June 26, 1917. Today's magnitude 4.7 event is significantly smaller than that historical record.
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Location
Authoritative source: USGS event page (event ID: us6000e3g9). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2021, April 15, 2021). M4.7 Earthquake south of Tonga — April 15, 2021. Retrieved June 19, 2021 from https://www.earthquaketracker.org/earthquakes/event/us6000e3g9/