explosion · reviewed by a seismologist
M 1.6ml
Earthquake near Sandy, OR
USGS: 6 km SSE of Sandy, Oregon
39 km (24 mi) SE of Portland, OR · 24 km (15 mi) SE of Gresham, OR
- When
- 1:33 pm PST on 27 November 2018 ()
- Where
- 6 km (4 mi) SSE of Sandy, OR · earthquakes near Sandy
- Magnitude
- M 1.6 (ml)
- Depth
- -1.3 km below the surface
- Felt
- no reports yet
- Nearest
- Clackamas County, 20 km S
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 2864 days ago
A magnitude 1.6 earthquake was recorded 6 km (4 mi) SSE of Sandy, OR, at 1:33 pm PST on 27 November 2018 (21:33 UTC). This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.
Earthquakes near other towns within 30 km: Estacada, Damascus, Mount Hood Village, Gresham, Beavercreek, Troutdale.
USGS catalogues this as explosion, not an earthquake.
How big was it?
This earthquake released about 7.1 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 2,100,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,500,000× the energy of this one
- Around the size people start to feel M 3.0 130× the energy of this one
- This earthquake M 1.6 about 7.1 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.
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 3 earthquakes of M5 or more within 50 km:
- 5.6 4 km E of Scotts Mills, Oregon · 44 km SW of this epicentre
- 5.2 5 km E of Bridgeton, Oregon · 40 km NW of this epicentre
- 5.0 3 km SW of Portland, Oregon · 40 km WNW 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 45.3413, -122.2420. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Clackamas County, OR | 20 km (13 mi) | S | earthquakes near Clackamas County |
| Multnomah County, OR | 27 km (17 mi) | NNW | earthquakes near Multnomah County |
| Hood River County, OR | 50 km (31 mi) | ENE | earthquakes near Hood River County |
| Clark County, WA | 51 km (32 mi) | NNW | earthquakes near Clark County |
| Marion County, OR | 56 km (35 mi) | SSW | earthquakes near Marion County |
| Washington County, OR | 71 km (44 mi) | WNW | earthquakes near Washington 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.
- 1.8 8 km SE of Molalla, Oregon
- 1.9 5 km ENE of Government Camp, Oregon
- 1.6 5 km ENE of Government Camp, Oregon
- 2.4 3 km WNW of Molalla, Oregon
- 2.6 6 km ESE of Scotts Mills, Oregon
- 1.8 5 km NW of Mount Hood Village, Oregon
- 1.5 4 km W of Mulino, Oregon
- 1.7 8 km SE of Molalla, Oregon
- 1.6 4 km SSW of Sandy, Oregon
- 1.5 8 km NE of Government Camp, Oregon
- 2.4 7 km NE of Government Camp, Oregon
- 1.6 1 km NNW of Walnut Grove, Washington
- 1.6 3 km NNW of Mount Hood Village, Oregon
- 1.6 3 km ENE of Government Camp, Oregon
- 1.6 3 km NNE of Government Camp, Oregon
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.