6.6

M6.6 Earthquake west of Macquarie Island — December 12, 2021

2021-12-12 08:58:07 UTC (2021-12-12) · approx. 6:58 PM UTC+10 local

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MagnitudeM6.6(mww)
Time08:58 UTC≈ 6:58 PM UTC+10
Depth10.0 kmshallow crustal
Coordinates-60.796°, 154.139°
Felt byNo felt reports
Status✓ Reviewed by USGS· green PAGER
green Alert— no significant casualties or damage expected

On December 12, 2021 at 08:58 UTC, a magnitude 6.6 shallow crustal earthquake struck west of Macquarie Island, at a depth of 10.0 km and coordinates -60.7956°, 154.1393°. 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 6.6 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.

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Map showing earthquake epicenter at -60.80°, 154.14°

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 M6.6 earthquake near west of Macquarie Island

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

Earthquake Details

Magnitude
6.6 mww
Depth
10.0 km
shallow crustal
Location
-60.7956°N
154.1393°E
Intensity (MMI)
0.0
weak

Technical Information

Event ID
us6000gbls
Event Type
earthquake
Status
✓ Reviewed
Significance
670
Azimuthal Gap
122.0°
Min Station Distance
6.821°
RMS Residual
0.58 sec
Last Updated
2025-12-22 22:15:13 UTC

Common Questions

How strong was the magnitude 6.6 earthquake west of Macquarie Island?

The magnitude 6.6 earthquake that struck west of Macquarie Island on December 12, 2021 at 08:58 UTC had a depth of 10.0 km. For context, this was a strong earthquake capable of causing significant damage.

Where did the earthquake occur?

The earthquake epicenter was located at -60.7956°, 154.1393°, which is west of Macquarie Island.

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

View on USGSDid You Feel It?

Authoritative source: USGS event page (event ID: us6000gbls). All scientific values on this page are sourced verbatim from the USGS feed.

Cite this page: EarthquakeTracker.org. (2021, December 12, 2021). M6.6 Earthquake west of Macquarie Island — December 12, 2021. Retrieved December 22, 2025 from https://www.earthquaketracker.org/earthquakes/event/us6000gbls/