6.5

M6.5 Earthquake in the Kermadec Islands region — March 4, 2021

2021-03-04 23:12:59 UTC (2021-03-04) · approx. 11:12 AM UTC-12 local

MagnitudeM6.5(mwb)
Time23:12 UTC≈ 11:12 AM UTC-12
Depth24.0 kmshallow crustal
Coordinates-28.517°, -176.680°
Felt byNo felt reports
Status✓ Reviewed by USGS· green PAGER
green Alert— no significant casualties or damage expected

On March 4, 2021 at 23:12 UTC, a magnitude 6.5 shallow crustal earthquake struck in the Kermadec Islands region, at a depth of 24.0 km and coordinates -28.5168°, -176.6801°. The USGS PAGER system issued a green alert level for this event, indicating no significant casualties or damage expected.

Physical scale: An earthquake of magnitude 6.5 releases seismic energy equivalent to roughly 85 kilotons of TNT. Empirical fault-scaling laws (Wells & Coppersmith, 1994) estimate the subsurface rupture length at approximately 18 km — a useful intuition for the size of the slip patch on the fault.

Map showing earthquake epicenter at -28.52°, -176.68°

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.

USGS ShakeMap intensity contours for the M6.5 earthquake near Kermadec Islands region

Source: U.S. Geological Survey ShakeMap. View interactive ShakeMap on USGS

Earthquake Details

Magnitude
6.5 mwb
Depth
24.0 km
shallow crustal
Location
-28.5168°N
-176.6801°E
Intensity (MMI)
3.7
light

Technical Information

Event ID
us7000dfq2
Event Type
earthquake
Status
✓ Reviewed
Significance
650
Azimuthal Gap
25.0°
Min Station Distance
11.764°
RMS Residual
0.64 sec
Last Updated
2025-12-22 19:06:45 UTC

Common Questions

How strong was the magnitude 6.5 earthquake in the Kermadec Islands region?

The magnitude 6.5 earthquake that struck in the Kermadec Islands region on March 4, 2021 at 23:12 UTC had a depth of 24.0 km. For context, this was a strong earthquake capable of causing significant damage.

Where did the earthquake occur?

The earthquake epicenter was located at -28.5168°, -176.6801°, which is in the Kermadec Islands region.

Were there aftershocks?

Aftershock activity is monitored continuously by the USGS. Aftershock sequences from magnitude 6.5 earthquakes can continue for weeks to months and gradually diminish over time.

Authoritative source: USGS event page (event ID: us7000dfq2). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2021, March 4, 2021). M6.5 Earthquake in the Kermadec Islands region — March 4, 2021. Retrieved December 22, 2025 from https://www.earthquaketracker.org/earthquakes/event/us7000dfq2/