Earthquake · reviewed by a seismologist
M 3.7mwr
12 km ENE of Ganges, Canada
Yes. A magnitude 3.7 earthquake was recorded 12 km ENE of Ganges, Canada, at 4:13 am PST on 17 December 2021 (12:13 UTC), 17 km deep. 1,016 people have reported feeling it to USGS.
- When
- Magnitude
- M 3.7 (mwr)
- Depth
- 17 km below the surface
- Felt
- 1,016 reports · strongest reported intensity IV
- Measured shaking
- intensity IV (ShakeMap)
- Nearest
- San Juan County, 47 km SSE
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 613 days ago
Earthquake alerts for Point Roberts, WA
Get a notification in this browser when USGS records an earthquake near Point Roberts, WA. 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 small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.
At this magnitude and depth, people at rest would likely notice it out to about 74 km (46 mi) from the epicentre. 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.
Likely felt in: Friday Harbor 47 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 5.4 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.7 would have released about 32 times as much.
- Northridge, California 1994 M 6.7 32,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 1,400× the energy of this one
- Magna, Utah 2020 M 5.7 1,000× the energy of this one
- This earthquake M 3.7 about 5.4 tons of TNT
- Around the size people start to feel M 3.0 this one released 11× more
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 48.8934, -123.3477. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| San Juan County, WA | 47 km (29 mi) | SSE | earthquakes near San Juan County |
| Island County, WA | 96 km (59 mi) | SSE | earthquakes near Island County |
| Clallam County, WA | 96 km (59 mi) | SSW | earthquakes near Clallam County |
| Whatcom County, WA | 111 km (69 mi) | E | earthquakes near Whatcom County |
| Skagit County, WA | 121 km (75 mi) | ESE | earthquakes near Skagit County |
| Snohomish County, WA | 149 km (93 mi) | SE | earthquakes near Snohomish County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
54 earthquakes have been recorded within 50 km since this one.
- 1.7 2 km SW of Point Roberts, Washington
- 1.8 3 km WSW of Point Roberts, Washington
- 1.7 2 km WSW of Point Roberts, Washington
- 1.6 2 km W of Point Roberts, Washington
- 2.8 10 km WSW of Friday Harbor, Washington
- 1.9 6 km NNE of Orcas, Washington
- 3.6 22 km NNE of Ganges, Canada
- 2.1 11 km E of North Saanich, Canada
- 4.0 12 km E of Saanichton, Canada
- 2.0 10 km NE of Saltair, Canada
- 1.7 12 km WNW of Orcas, Washington
- 1.6 9 km NW of Friday Harbor, Washington
- 1.6 6 km SSW of Saanichton, Canada
- 1.6 10 km WSW of Friday Harbor, Washington
- 1.9 1 km NE of Six Mile, Canada
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.