QuakeIndex

explosion · reviewed by a seismologist

M 1.6ml

Earthquake near Kalama, WA

No earthquake was likely felt in Kalama in the 24 hours to 3:18 am PST (11:18 UTC). The last one was M 3.0, 14 km (8 mi) S, at 7:25 am PDT on 22 October 2026, estimated intensity II (weak) in town; 113 felt reports to USGS. Every earthquake near Kalama

No: USGS classifies this as a explosion, not an earthquake. A magnitude 1.6 explosion was recorded 21 km (13 mi) east-northeast of Kalama, WA, at 12:59 pm PDT on 30 September 2025 (19:59 UTC), less than 1 km deep.

USGS: 21 km ENE of Kalama, Washington

61 km (38 mi) N of Portland, OR · 49 km (31 mi) N of Vancouver, WA

12:59 pm PDT, Sep 30, 2025 · · -0.5 km deep · released about 7.6 lb of TNT

10 km30 km60 km120 km N Cowlitz County 14 kmClark County 35 kmColumbia County 41 kmSkamania County 50 kmLewis County 58 kmMultnomah County 61 kmWahkiakum County 68 kmWashington County 71 kmClatsop County 86 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
12:59 pm PDT on 30 September 2025 ()
Where
21 km (13 mi) east-northeast of Kalama, WA · earthquakes near Kalama
Magnitude
M 1.6 (ml)
Depth
-0.5 km below the surface
Felt
no reports yet
Nearest
Cowlitz County, 14 km NNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 396 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

At this magnitude and depth, people at rest would likely notice it out to about 11 km (7 mi) from the epicentre. In Kalama, 21 km away, the estimate is intensity II (weak). Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.

Earthquakes near other towns within 30 km: Amboy, Woodland, La Center, Kelso, Rainier, Columbia City.

USGS catalogues this as explosion, not an earthquake.

How big was it?

This earthquake released about 7.6 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 2,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,400,000× the energy of this one
  3. Around the size people start to feel M 3.0 130× the energy of this one
  4. This earthquake M 1.6 about 7.6 lb of TNT

Energy from the Gutenberg–Richter relation (log10E = 1.5M + 4.8), rounded to two figures; bar length is magnitude, which is already a logarithm of energy. Magnitudes of past earthquakes from the USGS catalogue.

For this area

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record lists 16 earthquakes of M5 or more within 50 km; the five largest:

  1. 5.7 38 km NNE of Amboy, Washington · 34 km ENE of this epicentre
  2. 5.2 37 km NNE of Amboy, Washington · 33 km ENE of this epicentre
  3. 5.2 23 km S of Morton, Washington · 40 km NE of this epicentre
  4. 5.1 28 km ENE of Amboy, Washington · 37 km E of this epicentre
  5. 5.1 Washington · 36 km ENE of this epicentre

Since 2016: the QuakeIndex catalogue (US, M1.5+), built from the USGS FDSN event service. Before 2016: USGS ComCat, M5+ from 1900. Distances are between epicentres. This is the record, not a forecast.

Where

Epicentre 46.0817, -122.5907. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Cowlitz County, WA 14 km (9 mi) NNW earthquakes near Cowlitz County
Clark County, WA 35 km (22 mi) SSE earthquakes near Clark County
Columbia County, OR 41 km (25 mi) WSW earthquakes near Columbia County
Skamania County, WA 50 km (31 mi) E earthquakes near Skamania County
Lewis County, WA 58 km (36 mi) NNE earthquakes near Lewis County
Multnomah County, OR 61 km (38 mi) SSE earthquakes near Multnomah County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

50 earthquakes have been recorded within 50 km since this one.

  1. 1.8 4 km WSW of Yacolt, Washington
  2. 1.8 27 km N of Amboy, Washington
  3. 2.1 4 km W of Yacolt, Washington
  4. 1.8 3 km E of Kalama, Washington
  5. 2.3 37 km NNE of Amboy, Washington
  6. 1.5 3 km WSW of Kalama, Washington
  7. 1.6 2 km NE of Lewisville, Washington
  8. 2.6 18 km NE of Amboy, Washington
  9. 1.5 37 km NNE of Amboy, Washington
  10. 1.6 20 km E of Castle Rock, Washington
  11. 1.6 38 km NE of Amboy, Washington
  12. 2.1 4 km WSW of Yacolt, Washington
  13. 1.6 9 km S of Mossyrock, Washington
  14. 1.9 38 km NE of Amboy, Washington
  15. 1.6 5 km SSW of Yacolt, Washington

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of . QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.