M4.5 Earthquake near South Island of New Zealand — April 20, 2023
2023-04-20 19:37:35 UTC (2023-04-20) · approx. 7:37 AM UTC+12 local
Felt by 17 people across nearby locations.
On April 20, 2023 at 19:37 UTC, a magnitude 4.5 shallow crustal earthquake struck near South Island of New Zealand, at a depth of 17.2 km and coordinates -43.4998°, 172.7858°. This earthquake was detected by 21 seismic stations with good location accuracy and was assigned a USGS significance rating of 318, placing it among routine seismic activity.
Physical scale: An earthquake of magnitude 4.5 releases seismic energy equivalent to roughly 85 metric tons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 767 m — a useful intuition for the size of the slip patch on the fault.
The epicenter is located in New Zealand, a region characterized by the Hikurangi subduction zone in the North Island and the Alpine Fault in the South Island. The nearest mapped fault system is the Alpine Fault. View all earthquakes in New Zealand.
Learn more: Magnitude scale · Aftershock sequences
Did You Feel It? — community-reported shaking
Aggregated felt-report intensity from 17 citizen responses to the USGS Did You Feel It? system. Each colored zone represents the average MMI from reports in that area.
Source: U.S. Geological Survey Did You Feel It?. View on USGS · submit your own report
Earthquake Details
172.7858°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 4.5 earthquake near South Island of New Zealand?
The magnitude 4.5 earthquake that struck near South Island of New Zealand on April 20, 2023 at 19:37 UTC had a depth of 17.2 km. For context, this was a light earthquake commonly felt near the epicenter.
Where did the earthquake occur?
The earthquake epicenter was located at -43.4998°, 172.7858°, which is near South Island of New Zealand. View all earthquakes in New Zealand.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 4.5 earthquakes can continue for several days and gradually diminish over time.
Has New Zealand had earthquakes this big before?
The largest recorded earthquake in New Zealand was the M8.2 Wairarapa earthquake of January 23, 1855. Today's magnitude 4.5 event is significantly smaller than that historical record.
Authoritative source: USGS event page (event ID: us6000k5uz). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, April 20, 2023). M4.5 Earthquake near South Island of New Zealand — April 20, 2023. Retrieved July 3, 2023 from https://www.earthquaketracker.org/earthquakes/event/us6000k5uz/