M4.9 Earthquake 46 km SW of Pangai, Tonga — April 20, 2023
2023-04-20 13:55:54 UTC (2023-04-20) · approx. 1:55 AM UTC-12 local
On April 20, 2023 at 13:55 UTC, a magnitude 4.9 intermediate depth earthquake struck 46 km SW of Pangai, Tonga, at a depth of 80.2 km and coordinates -20.0765°, -174.7050°. This earthquake was detected by 43 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.
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
-174.7050°E
Technical Information
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Common Questions
How strong was the magnitude 4.9 earthquake near Pangai, Tonga?
The magnitude 4.9 earthquake that struck 46 km SW of Pangai, Tonga on April 20, 2023 at 13:55 UTC had a depth of 80.2 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at -20.0765°, -174.7050°, which is 46 km SW of Pangai, Tonga. View all earthquakes in Tonga.
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 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 4.9 event is significantly smaller than that historical record.
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Location
Authoritative source: USGS event page (event ID: us6000k5se). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, April 20, 2023). M4.9 Earthquake 46 km SW of Pangai, Tonga — April 20, 2023. Retrieved July 3, 2023 from https://www.earthquaketracker.org/earthquakes/event/us6000k5se/