Earthquake · reviewed by a seismologist
M 1.8md
Earthquake near Middletown, CA
No earthquake was likely felt in Middletown in the 24 hours to 2:39 am PST (10:39 UTC). The last one was M 1.6, 9 km (6 mi) WNW, at 5:12 am PST on 10 November 2026, estimated intensity II (weak) in town. Every earthquake near Middletown
This page: a magnitude 1.8 earthquake was recorded 2 km (1 mi) north-northeast of Middletown, CA, at 9:51 am PDT on 1 July 2018 (16:51 UTC), less than 1 km deep.
USGS: 2km NNE of Middletown, CA
37 km (23 mi) NNE of Santa Rosa, CA · 111 km (69 mi) N of San Francisco, CA
- When
- 9:51 am PDT on 1 July 2018 ()
- Where
- 2 km (1 mi) north-northeast of Middletown, CA · earthquakes near Middletown
- Magnitude
- M 1.8 (md)
- Depth
- 0.1 km below the surface
- Felt
- no reports yet
- Nearest
- Napa County, 38 km SE
- Nearest mapped fault
- Konocti Bay fault, 10 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 3054 days ago
Earthquake alerts for Middletown, CA
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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 14 km (9 mi) from the epicentre. In Middletown, 2 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: Cobb 12 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 16 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 5.8 970,000× the energy of this one
- Magna, Utah 2020 M 5.7 680,000× the energy of this one
- Around the size people start to feel M 3.0 61× the energy of this one
- This earthquake M 1.8 about 16 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 5.0 on 2016-12-14 — about 63,000 times the energy of this one.
Before 2016, the USGS record since 1900 lists no earthquake of M5 or more within 50 km.
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 38.7695, -122.6062. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Napa County, CA | 38 km (24 mi) | SE | earthquakes near Napa County |
| Sonoma County, CA | 39 km (24 mi) | SW | earthquakes near Sonoma County |
| Lake County, CA | 40 km (25 mi) | NNW | earthquakes near Lake County |
| Colusa County, CA | 55 km (34 mi) | NE | earthquakes near Colusa County |
| Yolo County, CA | 62 km (38 mi) | E | earthquakes near Yolo County |
| Solano County, CA | 81 km (50 mi) | SE | earthquakes near Solano County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
60 earthquakes have been recorded within 50 km since this one.
- 2.1 2km SE of Anderson Springs, CA
- 2.3 3km NNW of Larkfield-Wikiup, CA
- 1.7 3km WSW of Cobb, CA
- 1.5 6km NW of The Geysers, CA
- 1.8 7km NW of The Geysers, CA
- 1.5 2km NNW of Larkfield-Wikiup, CA
- 1.6 1km NNW of The Geysers, CA
- 2.1 7km NW of The Geysers, CA
- 2.5 3km NNW of Larkfield-Wikiup, CA
- 1.7 6km WNW of The Geysers, CA
- 1.9 13km E of Hidden Valley Lake, CA
- 1.8 11km E of Hidden Valley Lake, CA
- 1.6 6km W of Cobb, CA
- 2.0 6km NW of The Geysers, CA
- 2.0 13km ESE of Angwin, 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.