explosion · reviewed by a seismologist
M 1.6ml
Earthquake near Saint Helens, OR
No earthquake was likely felt in Saint Helens in the 24 hours to 12:31 am PST (08:31 UTC). The last one was M 3.0, 5 km (3 mi) WNW, at 7:25 am PDT on 22 October 2026, estimated intensity II (weak) in town; 113 felt reports to USGS. Every earthquake near Saint Helens
No: USGS classifies this as a explosion, not an earthquake. A magnitude 1.6 explosion was recorded 5 km (3 mi) west-northwest of Saint Helens, OR, at 2:31 pm PDT on 31 May 2018 (21:31 UTC), less than 1 km deep.
USGS: Washington-Oregon border region
41 km (26 mi) NNW of Portland, OR · 34 km (21 mi) NW of Vancouver, WA
- When
- 2:31 pm PDT on 31 May 2018 ()
- Where
- 5 km (3 mi) west-northwest of Saint Helens, OR · earthquakes near Saint Helens
- Magnitude
- M 1.6 (ml)
- Depth
- -0.5 km below the surface
- Felt
- no reports yet
- Nearest
- Columbia County, 18 km WNW
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 3087 days ago
Earthquake alerts for Saint Helens, OR
Get a notification in this browser when USGS records an earthquake near Saint Helens, OR. No account or email needed.
Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
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 Saint Helens, 5 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: Columbia City, Warren, Woodland, Ridgefield, Scappoose, Kalama.
USGS catalogues this as explosion, not an earthquake.
How big was it?
This earthquake released about 8.1 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.
- Mineral, Virginia 2011 M 5.8 1,900,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,300,000× the energy of this one
- Around the size people start to feel M 3.0 120× the energy of this one
- This earthquake M 1.6 about 8.1 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.
Where
Epicentre 45.8767, -122.8702. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Columbia County, OR | 18 km (11 mi) | WNW | earthquakes near Columbia County |
| Clark County, WA | 32 km (20 mi) | ESE | earthquakes near Clark County |
| Cowlitz County, WA | 39 km (24 mi) | NNE | earthquakes near Cowlitz County |
| Washington County, OR | 40 km (25 mi) | SSW | earthquakes near Washington County |
| Multnomah County, OR | 51 km (32 mi) | SE | earthquakes near Multnomah County |
| Wahkiakum County, WA | 63 km (39 mi) | NW | earthquakes near Wahkiakum County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
56 earthquakes have been recorded within 50 km since this one.
- 2.2 3 km ESE of Woodland, Washington
- 1.7 3 km NW of West Longview, Washington
- 1.6 16 km ENE of Kalama, Washington
- 1.8 0 km SW of Kalama, Washington
- 1.6 1 km SSW of Cherry Grove, Washington
- 1.5 4 km NW of North Portland, Oregon
- 1.8 24 km N of Amboy, Washington
- 1.9 6 km NNW of West Longview, Washington
- 1.5 Washington-Oregon border region
- 1.8 12 km NNW of Amboy, Washington
- 1.7 11 km WNW of Warren, Oregon
- 2.0 8 km S of Scappoose, Oregon
- 1.6 20 km NE of Kalama, Washington
- 1.6 8 km E of Kalama, Washington
- 1.5 2 km NNW of Venersborg, 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
- The official USGS event page — the source of record for every value above
- Did you feel it? Report it to USGS — reports go to USGS, not to us
- ShakeMap for this event, when USGS has produced one
QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.