Earthquake · reviewed by a seismologist
M 1.8ml
Earthquake near Portland, OR
No earthquake was likely felt in Portland in the 24 hours to 4:33 am PST (12:33 UTC). The last one was M 4.4, 110 km (68 mi) S, at 5:52 am PDT on 7 October 2022, estimated intensity II (weak) in town; 6,105 felt reports to USGS. Every earthquake near Portland
This page: a magnitude 1.8 earthquake was recorded 48 km (30 mi) north-northwest of Portland, OR, at 9:45 pm PDT on 26 September 2020 (04:45 UTC), 21 km deep.
USGS: 2 km NE of Deer Island, Oregon
47 km (29 mi) NNW of Portland, OR · 38 km (24 mi) NNW of Vancouver, WA
- When
- 9:45 pm PDT on 26 September 2020 ()
- Where
- 48 km (30 mi) north-northwest of Portland, OR · earthquakes near Portland
- Magnitude
- M 1.8 (ml)
- Depth
- 21 km below the surface
- Felt
- no reports yet
- Nearest
- Columbia County, 20 km W
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 2237 days ago
Earthquake alerts for Portland, OR
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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 it was probably too small to be felt, even directly above it. In Portland, 48 km away, the estimate is intensity I (not felt). 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, Kalama, Woodland, Saint Helens, Warren, La Center.
How big was it?
This earthquake released about 13 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 1,200,000× the energy of this one
- Magna, Utah 2020 M 5.7 840,000× the energy of this one
- Around the size people start to feel M 3.0 75× the energy of this one
- This earthquake M 1.8 about 13 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 one earthquake of M5 or more within 50 km:
- 5.2 5 km E of Bridgeton, Oregon · 42 km SSE 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 45.9458, -122.8198. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Columbia County, OR | 20 km (13 mi) | W | earthquakes near Columbia County |
| Cowlitz County, WA | 30 km (19 mi) | NNE | earthquakes near Cowlitz County |
| Clark County, WA | 32 km (20 mi) | SE | earthquakes near Clark County |
| Washington County, OR | 49 km (30 mi) | SSW | earthquakes near Washington County |
| Multnomah County, OR | 54 km (34 mi) | SE | earthquakes near Multnomah County |
| Wahkiakum County, WA | 61 km (38 mi) | NW | earthquakes near Wahkiakum County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
58 earthquakes have been recorded within 50 km since this one.
- 2.0 4 km SE of Mill Plain, Washington
- 2.1 11 km ENE of Prescott, Oregon
- 1.6 4 km NNW of Lewisville, Washington
- 2.6 3 km SE of Mill Plain, Washington
- 1.6 15 km E of Castle Rock, Washington
- 1.6 9 km NE of Vernonia, Oregon
- 1.7 1 km WSW of Kalama, Washington
- 2.0 21 km E of Castle Rock, Washington
- 1.6 2 km ESE of Lewisville, Washington
- 2.8 21 km E of Castle Rock, Washington
- 1.5 21 km E of Castle Rock, Washington
- 2.5 21 km E of Castle Rock, Washington
- 1.5 28 km N of Amboy, Washington
- 1.7 2 km WSW of Columbia City, Oregon
- 1.7 16 km NNE of Amboy, 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.