EARTHQUAKEM4.2

M4.2 earthquake near Wauna, Washington

Map: the earthquake near Wauna, Washington, with plate boundaries

A magnitude 4.2 earthquake struck 4 mi (6 km) west-northwest of Wauna, Washington on Tuesday, September 29, 2026 at 21:05 UTC, at a depth of 17 mi (28 km), according to the U.S. Geological Survey. Shallow quakes like this one shake the surface hardest. The nearest city of a million or more people is Seattle, Washington, about 21 mi (34 km) away.

USGS’s PAGER impact estimate is GREEN: little or no damage expected.

9,571 people reported feeling it to USGS “Did You Feel It?”.

MagnitudeM4.2
Depth17 mi (28 km)
Time (UTC)Sep 29 21:05
Location47.40°N 122.72°W
Nearest townWauna · 6 km
Energy30 tons TNT
Aftershocks M2.5+0
Tsunami flagNo
PAGER alertGREEN
Felt reports9,571
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Why here?

This earthquake struck about 156 mi (251 km) from the nearest major plate boundary, which makes it an intraplate earthquake. These happen on old faults inside a plate, where stress from the plate’s slow movement is released. They are less common, but can surprise areas that rarely feel quakes.

The red lines on the map are plate boundaries.

What kind of fault?

USGS’s analysis of the seismic waves shows it was a strike-slip earthquake: the two sides of the fault slid past each other sideways, like California’s San Andreas Fault.

Shaking and impact

The strongest shaking USGS estimates was intensity 3 on the Modified Mercalli scale: weak. USGS’s PAGER system estimates it most likely caused no deaths (95 percent probability). Early estimates are revised as reports come in.

How strong was it?

Magnitude is logarithmic: each whole step releases about 32 times more energy. This magnitude 4.2 released roughly the energy of 30 tons of TNT. The strongest earthquake ever recorded, magnitude 9.5 in Chile in 1960, released about 89,000,000 times more than this one.

Aftershocks

In the first 26 days after it, USGS recorded no smaller earthquakes of magnitude 2.5 or more within 62 mi (100 km).

Earthquake history here

Before this earthquake, USGS had recorded 6 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 September 29, 2026 or earthquakes by day.

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