Earthquake · reviewed by a seismologist
M 1.6md
Earthquake near Boonville, CA
No earthquake was likely felt in Boonville in the 24 hours to 1:34 pm PST (21:34 UTC). The last one was M 4.0, 65 km (41 mi) NNE, at 5:01 am PDT on 28 October 2026, estimated intensity II (weak) in town; 14 felt reports to USGS. Every earthquake near Boonville
This page: a magnitude 1.6 earthquake was recorded 6 km (4 mi) northwest of Boonville, CA, at 9:23 pm PDT on 19 September 2021 (04:23 UTC), less than 1 km deep.
USGS: 6km NW of Boonville, CA
91 km (57 mi) NW of Santa Rosa, CA
- When
- 9:23 pm PDT on 19 September 2021 ()
- Where
- 6 km (4 mi) northwest of Boonville, CA · earthquakes near Boonville
- Magnitude
- M 1.6 (md)
- Depth
- -0.5 km below the surface
- Felt
- no reports yet
- Nearest
- Mendocino County, 43 km N
- Nearest mapped fault
- San Andreas fault, 22 km from its surface trace — near is not the same as on
- Status
- Reviewed by a seismologist
USGS · last changed by USGS · we first saw it 1879 days ago
Earthquake alerts for Boonville, CA
Get a notification in this browser when USGS records an earthquake near Boonville, CA. 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 Boonville, 6 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.
Likely felt in: Boonville 6 km, intensity II. Estimated for each town centre; each link is that town's own record.
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
The largest earthquake within 50 km since 2016 was M 4.4 on 2020-12-06 — about 16,000 times the energy of this one.
Before 2016, the USGS record lists one earthquake of M5 or more within 50 km:
- 5.2 6 km ESE of Talmage, California · 29 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 39.0463, -123.4232. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Mendocino County, CA | 43 km (27 mi) | N | earthquakes near Mendocino County |
| Lake County, CA | 59 km (37 mi) | E | earthquakes near Lake County |
| Sonoma County, CA | 72 km (45 mi) | SE | earthquakes near Sonoma County |
| Colusa County, CA | 103 km (64 mi) | E | earthquakes near Colusa County |
| Glenn County, CA | 107 km (67 mi) | NE | earthquakes near Glenn County |
| Napa County, CA | 112 km (70 mi) | ESE | earthquakes near Napa County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
49 earthquakes have been recorded within 50 km since this one.
- 2.1 16km SW of Lakeport, CA
- 1.6 4km S of Redwood Valley, CA
- 1.8 8km NW of Redwood Valley, CA
- 1.8 2km E of Willits, CA
- 1.5 7km ENE of Brooktrails, CA
- 2.4 6km WNW of North Lakeport, CA
- 1.6 7km NE of Willits, CA
- 2.0 10km NNW of Redwood Valley, CA
- 1.8 9km NNW of Redwood Valley, CA
- 2.5 13km SE of Talmage, CA
- 1.7 20km ESE of Navarro Head, CA
- 1.7 4km E of Redwood Valley, CA
- 2.1 4km E of Redwood Valley, CA
- 1.5 9km S of Boonville, CA
- 2.2 10km ESE of Willits, CA
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.