M4.2 Earthquake 80 km NNW of Hihifo, Tonga — October 18, 2023
2023-10-18 21:30:20 UTC (2023-10-18) · approx. 9:30 AM UTC-12 local
On October 18, 2023 at 21:30 UTC, a magnitude 4.2 shallow crustal earthquake struck 80 km NNW of Hihifo, Tonga, at a depth of 61.1 km and coordinates -15.2480°, -173.9574°.
Physical scale: An earthquake of magnitude 4.2 releases seismic energy equivalent to roughly 30 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 476 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
-173.9574°E
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Common Questions
How strong was the magnitude 4.2 earthquake near Hihifo, Tonga?
The magnitude 4.2 earthquake that struck 80 km NNW of Hihifo, Tonga on October 18, 2023 at 21:30 UTC had a depth of 61.1 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 4.2 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 4.2 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us6000lhip). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, October 18, 2023). M4.2 Earthquake 80 km NNW of Hihifo, Tonga — October 18, 2023. Retrieved December 26, 2023 from https://www.earthquaketracker.org/earthquakes/event/us6000lhip/