EARTHQUAKEM5.0

M5.0 earthquake in the Pagan region, Northern Mariana Islands

Map: the earthquake in the Pagan region, Northern Mariana Islands, with plate boundaries

A magnitude 5.0 earthquake struck in the Pagan region, Northern Mariana Islands on Tuesday, October 20, 2026 at 02:54 UTC, at a depth of 129 km (80 mi), according to the U.S. Geological Survey. At this intermediate depth, shaking spreads out before it reaches the surface. The epicenter was about 340 km (211 mi) north of Capitol Hill.

MagnitudeM5.0
Depth129 km (80 mi)
Time (UTC)Oct 20 02:54
Location18.25°N 146.03°E
Nearest townCapitol Hill · 340 km
Energy477 tons TNT
Aftershocks M2.5+1
Tsunami flagNo
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Why here?

This earthquake struck about 138 km (86 mi) from the boundary between the Philippine Sea and Mariana 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 129 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 5.0 released roughly the energy of 477 tons of TNT. That is about 32 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 5,600,000 times more than this one.

Aftershocks

In the first 6 days after it, USGS recorded 1 smaller earthquake of magnitude 2.5 or more within 100 km (62 mi). It was a magnitude 4.9 on October 20 at 07:09 UTC.

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 67 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 20, 2026 or earthquakes by day.

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