M5.6 Earthquake in the Kermadec Islands region — September 21, 2024
2024-09-21 02:32:17 UTC (2024-09-21) · approx. 2:32 PM UTC-12 local
Aftershock of the M5.8 mainshock.
On September 21, 2024 at 02:32 UTC, a magnitude 5.6 shallow crustal earthquake struck in the Kermadec Islands region, at a depth of 9.0 km and coordinates -29.0640°, -176.4824°. The USGS PAGER system issued a green alert level for this event, indicating no significant casualties or damage expected. This earthquake was detected by 59 seismic stations with excellent location accuracy and was assigned a USGS significance rating of 482, placing it among routine seismic activity.
Physical scale: An earthquake of magnitude 5.6 releases seismic energy equivalent to roughly 4 kilotons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 4.4 km — a useful intuition for the size of the slip patch on the fault.
This earthquake is part of an ongoing aftershock sequence following the magnitude 5.8 mainshock that occurred 9 days ago in the Kermadec Islands region. Since the mainshock, the USGS has recorded 8 aftershocks in this area. Aftershock activity is expected to continue for days to weeks as stresses on surrounding faults redistribute.
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
Earthquake Details
-176.4824°E
Technical Information
Nearby Earthquakes (Last 7 Days)
Common Questions
How strong was the magnitude 5.6 earthquake in the Kermadec Islands region?
The magnitude 5.6 earthquake that struck in the Kermadec Islands region on September 21, 2024 at 02:32 UTC had a depth of 9.0 km. For context, this was a moderate earthquake that could be widely felt.
Where did the earthquake occur?
The earthquake epicenter was located at -29.0640°, -176.4824°, which is in the Kermadec Islands region.
Were there aftershocks?
Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 5.6 earthquakes can continue for days to weeks and gradually diminish over time.
Is this the same earthquake as the M5.8 one earlier?
No. This magnitude 5.6 earthquake is an aftershock of the larger magnitude 5.8 mainshock that occurred earlier in the Kermadec Islands region. Aftershocks are smaller earthquakes triggered by stress changes from the mainshock.
Actions
Authoritative source: USGS event page (event ID: us6000ntf1). All scientific values on this page are sourced verbatim from the USGS feed.
Cite this page: EarthquakeTracker.org. (2024, September 21, 2024). M5.6 Earthquake in the Kermadec Islands region — September 21, 2024. Retrieved November 23, 2024 from https://www.earthquaketracker.org/earthquakes/event/us6000ntf1/