Shallow M6.0 earthquake hits Kermadec Islands region

The epicenter was located far from populated areas, about 830 km (516 miles) SSW of ‘Ohonua, Tonga, and 1 088 km (676 miles) NE of Whangarei, New Zealand.

The USGS issued a Green alert for shaking-related fatalities and economic losses. There is a low likelihood of casualties and damage.

There is no tsunami threat from this earthquake.

Overall, the population in this region resides in structures that are highly resistant to earthquake shaking, though some vulnerable structures exist. The predominant vulnerable building types are reinforced masonry and unreinforced brick with timber floor construction.

This was the second M6+ earthquake in this region on May 31, after M6.1 at 14:28 UTC, and was followed by a third — M6.2 at 22:26 UTC.

The Kermadec–Tonga subduction zone generates many large earthquakes on the interface between the descending Pacific and overriding Australia plates, within the two plates themselves, and, less frequently, near the outer rise of the Pacific plate east of the trench.

Since 1900, 40 M7.5+ earthquakes have been recorded, mostly north of 30°S. However, it is unclear whether any of the few historic M8+ events that have occurred close to the plate boundary were underthrusting events on the plate interface, or were intraplate earthquakes.

On September 29, 2009, one of the largest normal fault (outer rise) earthquakes ever recorded (M8.1) occurred south of Samoa, 40 km (25 miles) east of the Tonga trench. The earthquake generated a tsunami that killed at least 180 people. Maximum wave heights were measured at over 12 m (39 feet) in Samoa, more than 17 m (56 feet) in American Samoa, and up to 22 m (72 feet) in Tonga, resulting in widespread coastal devastation.

Estimated population exposure to earthquake shaking

Regional seismicity

References:

¹ M6.0 earthquake Kermadec Islands – USGS – May 31, 2025

² M6.0 earthquake Kermadec Islands – EMSC – May 31, 2025