M5.5 Earthquake: West of Macquarie Island

Key context

Tectonic setting

Macquarie Ridge. The Macquarie Ridge south of New Zealand is a transform boundary where the Australian and Pacific plates slide past each other. It produced a M8.2 quake in 1989 and has frequent M5-6 events, almost all far from people.

The USGS moment tensor shows strike-slip faulting: the two sides of the fault slid sideways past each other.

At 10 km it was a very shallow quake: shallow quakes shake the ground above them hardest, so local damage depends on how close towns are.

Shaking and impact

USGS PAGER estimates the impact from the shaking and the number of people exposed. For this quake it issued a green alert: little or no damage and a low chance of deaths (fatality alert: green, economic loss alert: green). PAGER is an early estimate and can change as reports come in.

USGS had no "Did You Feel It?" reports for this quake when this page was updated; remote and offshore quakes often get none.

Aftershocks

This page counts quakes of M2.5 or more within 50 km after the main shock, from the USGS catalog (last checked 09:05 UTC, 29 Oct 2026): 0 aftershocks so far.

Aftershocks are normal after a quake of this size. They usually become less frequent over days and weeks, but a strong aftershock can still happen, and in a few sequences a later quake is larger. No one can predict their exact time or size; follow the official agency for your area.

Earthquake history within 250 km

Since 1976, USGS lists 110 quakes of M5 or more within 250 km of this epicentre, about 2.2 a year. Since 1900 the same circle had 69 quakes of M5.5 or larger.

Official information

• EMSC (European-Mediterranean Seismological Centre)
• USGS event page for this quake (ShakeMap, PAGER, felt reports)
• tsunami.gov for US tsunami bulletins

Data status

USGS review status: reviewed. Magnitude type: mww. USGS last updated this event on 18 Oct 2026 at 05:46 UTC. Magnitude, depth and location can still be revised; this page keeps the same address if they change.