M6.6 Earthquake south of the Kermadec Islands — September 8, 2023
2023-09-08 09:09:57 UTC (2023-09-08) · approx. 9:09 PM UTC-12 local
Felt by 22 people across nearby locations. Maximum shaking intensity MMI 6.2 (very strong).
On September 8, 2023 at 09:09 UTC, a magnitude 6.6 intermediate depth earthquake struck south of the Kermadec Islands, at a depth of 79.0 km and coordinates -32.7996°, -179.3741°. The earthquake was reported felt by 22 peopleacross nearby locations, with a maximum shaking intensity of Modified Mercalli Intensity (MMI) 6.2 (very strong). The USGS PAGER system issued a green alert level for this event, indicating no significant casualties or damage expected. This earthquake was detected by 171 seismic stations with excellent location accuracy and was assigned a USGS significance rating of 679, making it a moderate-impact event.
Physical scale: An earthquake of magnitude 6.6 releases seismic energy equivalent to roughly 120 kilotons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 22 km — a useful intuition for the size of the slip patch on the fault.
ShakeMap — predicted shaking intensity
Modeled ground-motion intensity contoured on the Modified Mercalli scale (MMI). Computed by the USGS from the moment-tensor solution and regional ground-motion prediction equations.
Source: U.S. Geological Survey ShakeMap. View interactive ShakeMap on USGS
Did You Feel It? — community-reported shaking
Aggregated felt-report intensity from 22 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
-179.3741°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 6.6 earthquake south of the Kermadec Islands?
The magnitude 6.6 earthquake that struck south of the Kermadec Islands on September 8, 2023 at 09:09 UTC had a depth of 79.0 km. It was felt by 22 people with maximum shaking intensity of MMI 6.2 (very strong). For context, this was a strong earthquake capable of causing significant damage.
Where did the earthquake occur?
The earthquake epicenter was located at -32.7996°, -179.3741°, which is south of the Kermadec Islands.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 6.6 earthquakes can continue for weeks to months and gradually diminish over time.
Actions
Authoritative source: USGS event page (event ID: us7000ku47). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2023, September 8, 2023). M6.6 Earthquake south of the Kermadec Islands — September 8, 2023. Retrieved November 17, 2023 from https://www.earthquaketracker.org/earthquakes/event/us7000ku47/