M4.0 Earthquake 175 km E of Hicks Bay, New Zealand — October 21, 2023
2023-10-21 18:04:45 UTC (2023-10-21) · approx. 6:04 AM UTC-12 local
On October 21, 2023 at 18:04 UTC, a magnitude 4.0 shallow crustal earthquake struck 175 km E of Hicks Bay, New Zealand, at a depth of 20.4 km and coordinates -37.3478°, -179.7462°.
Physical scale: An earthquake of magnitude 4.0 releases seismic energy equivalent to roughly 15 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 347 m — a useful intuition for the size of the slip patch on the fault.
Earthquake Details
-179.7462°E
Technical Information
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Common Questions
How strong was the magnitude 4.0 earthquake near Hicks Bay, New Zealand?
The magnitude 4.0 earthquake that struck 175 km E of Hicks Bay, New Zealand on October 21, 2023 at 18:04 UTC had a depth of 20.4 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 4.0 earthquakes can continue for several days and gradually diminish over time.
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Understanding This Data
Magnitude 4.0 earthquakes are often felt but rarely cause damage.
Authoritative source: USGS event page (event ID: us7000l69u). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, October 21, 2023). M4.0 Earthquake 175 km E of Hicks Bay, New Zealand — October 21, 2023. Retrieved December 26, 2023 from https://www.earthquaketracker.org/earthquakes/event/us7000l69u/