Earthquake · reviewed by a seismologist
M 1.8md
Earthquake near Upper Lake, CA
No earthquake was likely felt in Upper Lake in the 24 hours to 10:31 pm PST (06:31 UTC). The last one was M 1.6, 8 km (5 mi) W, at 4:31 am PST on 10 November 2026, estimated intensity II (weak) in town. Every earthquake near Upper Lake
This page: a magnitude 1.8 earthquake was recorded 20 km (12 mi) north-northeast of Upper Lake, CA, at 7:08 pm PDT on 20 October 2017 (02:08 UTC), 9.2 km deep.
USGS: 19 km NNE of Upper Lake, California
- When
- 7:08 pm PDT on 20 October 2017 ()
- Where
- 20 km (12 mi) north-northeast of Upper Lake, CA · earthquakes near Upper Lake
- Magnitude
- M 1.8 (md)
- Depth
- 9.2 km below the surface
- Felt
- no reports yet
- Nearest
- Lake County, 24 km S
- Nearest mapped fault
- Bartlett Springs fault system, 4 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 3309 days ago
Earthquake alerts for Upper Lake, CA
Get a notification in this browser when USGS records an earthquake near Upper Lake, 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 10 km (6 mi) from the epicentre. In Upper Lake, 20 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.
Earthquakes near other towns within 30 km: Nice, North Lakeport.
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
The largest earthquake within 50 km since 2016 was M 5.1 on 2016-08-10 — about 92,000 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 · 34 km SW 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 39.3187, -122.7972. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Lake County, CA | 24 km (15 mi) | S | earthquakes near Lake County |
| Glenn County, CA | 46 km (29 mi) | NE | earthquakes near Glenn County |
| Colusa County, CA | 51 km (31 mi) | ESE | earthquakes near Colusa County |
| Mendocino County, CA | 57 km (35 mi) | WNW | earthquakes near Mendocino County |
| Sonoma County, CA | 89 km (55 mi) | S | earthquakes near Sonoma County |
| Napa County, CA | 99 km (62 mi) | SSE | earthquakes near Napa 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.
- 1.7 13km S of Lake Pillsbury, CA
- 1.6 19km ESE of Lake Pillsbury, CA
- 1.6 7km E of Clearlake Oaks, CA
- 1.9 17km SE of Lake Pillsbury, CA
- 2.5 10km NNE of Cloverdale, CA
- 2.0 8km NNE of Clearlake, CA
- 2.2 16km WNW of Lake Pillsbury, CA
- 2.2 8km W of Redwood Valley, CA
- 2.2 8km W of Redwood Valley, CA
- 1.5 10km SSE of Talmage, CA
- 2.0 25km W of Alder Springs, CA
- 1.7 18km NNW of Lake Pillsbury, CA
- 1.7 8km W of Redwood Valley, CA
- 1.5 18km SE of Lake Pillsbury, CA
- 2.6 4km ENE 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.