EARTHQUAKEM4.5

M4.5 earthquake near Hihifo, Tonga

Map: the earthquake near Hihifo, Tonga, with plate boundaries

A magnitude 4.5 earthquake struck 61 km (38 mi) north of Hihifo, Tonga on Saturday, October 10, 2026 at 08:38 UTC, at a depth of 79 km (49 mi), according to the U.S. Geological Survey. At this intermediate depth, shaking spreads out before it reaches the surface.

MagnitudeM4.5
Depth79 km (49 mi)
Time (UTC)Oct 10 08:38
Location15.40°S 173.78°W
Nearest townHihifo · 61 km
Energy85 tons TNT
Aftershocks M2.5+0
Tsunami flagNo
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Why here?

This earthquake struck about 95 km (59 mi) from the boundary between the Pacific and Australian plates. Most earthquakes happen along plate boundaries like this one, where the pieces of Earth’s outer shell collide, pull apart or grind past each other. Stress builds up over years until the rock suddenly slips. At 79 km down, it most likely broke inside a plate that is sinking into the mantle beneath its neighbor, in what geologists call a subduction zone.

The red lines on the map are plate boundaries.

How strong was it?

Magnitude is logarithmic: each whole step releases about 32 times more energy. This magnitude 4.5 released roughly the energy of 85 tons of TNT. That is about 5.6 times the energy of a magnitude 4.0, a quake people nearby feel but that rarely causes damage. The strongest earthquake ever recorded, magnitude 9.5 in Chile in 1960, released about 32,000,000 times more than this one.

Aftershocks

In the first 16 days after it, USGS recorded no smaller earthquakes of magnitude 2.5 or more within 100 km (62 mi).

A stronger magnitude 5.2 followed on October 15 at 13:29 UTC, about 52 km (32 mi) away, so this one is now considered a foreshock.

Outside the United States, USGS mainly lists quakes of about magnitude 4 and up, so smaller aftershocks there are undercounted.

Earthquake history here

Before this earthquake, USGS had recorded 262 earthquakes of magnitude 6 or larger within 300 km (186 mi) since 1900. The strongest:

Official details, updates and the shaking map: USGS event page.

See every earthquake on October 10, 2026 or earthquakes by day.

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