explosion · reviewed by a seismologist
M 1.8ml
Earthquake near Amboy, WA
No earthquake was likely felt in Amboy in the 24 hours to 3:08 am PST (11:08 UTC). The last one was M 1.6, 11 km (7 mi) S, at 4:25 pm PDT on 19 October 2026, estimated intensity II (weak) in town. Every earthquake near Amboy
No: USGS classifies this as a explosion, not an earthquake. A magnitude 1.8 explosion was recorded 29 km (18 mi) north of Amboy, WA, at 12:39 pm PST on 30 November 2018 (20:39 UTC), less than 1 km deep. 4 people have reported feeling it to USGS.
USGS: 28 km N of Amboy, Washington
73 km (45 mi) NNE of Portland, OR
- When
- 12:39 pm PST on 30 November 2018 ()
- Where
- 29 km (18 mi) north of Amboy, WA · earthquakes near Amboy
- Magnitude
- M 1.8 (ml)
- Depth
- -1.3 km below the surface
- Felt
- 4 reports · strongest reported intensity II
- Nearest
- Cowlitz County, 21 km W
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 2904 days ago
Earthquake alerts for Amboy, WA
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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 13 km (8 mi) from the epicentre. In Amboy, 29 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.
USGS catalogues this as explosion, not an earthquake.
How big was it?
This earthquake released about 14 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 1,100,000× the energy of this one
- Magna, Utah 2020 M 5.7 760,000× the energy of this one
- Around the size people start to feel M 3.0 68× the energy of this one
- This earthquake M 1.8 about 14 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:
- 5.7 38 km NNE of Amboy, Washington · 18 km ENE of this epicentre
- 5.2 37 km NNE of Amboy, Washington · 17 km ENE of this epicentre
- 5.2 23 km S of Morton, Washington · 24 km NE of this epicentre
- 5.1 28 km ENE of Amboy, Washington · 28 km SE of this epicentre
- 5.1 Washington · 20 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 46.1680, -122.4142. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Cowlitz County, WA | 21 km (13 mi) | W | earthquakes near Cowlitz County |
| Skamania County, WA | 39 km (24 mi) | ESE | earthquakes near Skamania County |
| Clark County, WA | 44 km (28 mi) | S | earthquakes near Clark County |
| Lewis County, WA | 46 km (29 mi) | N | earthquakes near Lewis County |
| Columbia County, OR | 57 km (36 mi) | WSW | earthquakes near Columbia County |
| Multnomah County, OR | 69 km (43 mi) | S | earthquakes near Multnomah County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
59 earthquakes have been recorded within 50 km since this one.
- 1.7 1 km NE of Lewisville, Washington
- 1.8 2 km NE of Deer Island, Oregon
- 1.6 3 km WSW of Yacolt, Washington
- 1.6 14 km SSW of Morton, Washington
- 1.6 21 km SSE of Mossyrock, Washington
- 1.6 5 km SW of Deer Island, Oregon
- 1.5 3 km SW of Yacolt, Washington
- 1.8 9 km S of Toledo, Washington
- 1.7 6 km ENE of Prescott, Oregon
- 1.6 9 km SSE of Toledo, Washington
- 1.6 12 km SSE of Toledo, Washington
- 1.7 13 km ESE of Yacolt, Washington
- 1.8 20 km NNW of Carson, Washington
- 2.2 3 km ESE of Woodland, Washington
- 1.6 4 km W of Mossyrock, 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.