M4.6 Earthquake 44 km W of Hihifo, Tonga — October 28, 2023
2023-10-28 20:59:53 UTC (2023-10-28) · approx. 8:59 AM UTC-12 local
On October 28, 2023 at 20:59 UTC, a magnitude 4.6 intermediate depth earthquake struck 44 km W of Hihifo, Tonga, at a depth of 146.3 km and coordinates -15.9474°, -174.2112°. This earthquake was detected by 24 seismic stations with excellent location accuracy and was assigned a USGS significance rating of 326, placing it among routine seismic activity.
Physical scale: An earthquake of magnitude 4.6 releases seismic energy equivalent to roughly 120 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 899 m — 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
-174.2112°E
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Common Questions
How strong was the magnitude 4.6 earthquake near Hihifo, Tonga?
The magnitude 4.6 earthquake that struck 44 km W of Hihifo, Tonga on October 28, 2023 at 20:59 UTC had a depth of 146.3 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at -15.9474°, -174.2112°, which is 44 km W of Hihifo, Tonga. View all earthquakes in Tonga.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.6 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 4.6 event is significantly smaller than that historical record.
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Location
Authoritative source: USGS event page (event ID: us7000l8cm). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, October 28, 2023). M4.6 Earthquake 44 km W of Hihifo, Tonga — October 28, 2023. Retrieved January 4, 2024 from https://www.earthquaketracker.org/earthquakes/event/us7000l8cm/