Earthquake · reviewed by a seismologist
M 1.5md
Earthquake near Penngrove, CA
No earthquake was likely felt in Penngrove in the 24 hours to 3:01 am PST (11:01 UTC). The last one was M 1.9, 15 km (9 mi) NE, at 3:31 am PDT on 11 October 2026, estimated intensity II (weak) in town. Every earthquake near Penngrove
This page: a magnitude 1.5 earthquake was recorded 3 km (2 mi) east of Penngrove, CA, at 8:39 am PDT on 9 May 2023 (15:39 UTC), 6.3 km deep.
USGS: 3km E of Penngrove, CA
6 km (4 mi) N of Petaluma, CA · 61 km (38 mi) NNW of San Francisco, CA
- When
- 8:39 am PDT on 9 May 2023 ()
- Where
- 3 km (2 mi) east of Penngrove, CA · earthquakes near Penngrove
- Magnitude
- M 1.5 (md)
- Depth
- 6.3 km below the surface
- Felt
- no reports yet
- Nearest
- Marin County, 30 km SSW
- Nearest mapped fault
- Rodgers Creek fault, 6 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 1282 days ago
Earthquake alerts for Penngrove, CA
Get a notification in this browser when USGS records an earthquake near Penngrove, 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 8 km (5 mi) from the epicentre. In Penngrove, 3 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: Petaluma 8 km, intensity II · Rohnert Park 8 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 5.7 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.5 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 2,600,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,900,000× the energy of this one
- Around the size people start to feel M 3.0 170× the energy of this one
- This earthquake M 1.5 about 5.7 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 2022-09-14 — about 20,000 times the energy of this one.
Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:
- 6.0 The 2014 South Napa, California Earthquake · 29 km ESE of this epicentre
- 5.3 3 km E of Bloomfield, California · 16 km W of this epicentre
- 5.3 Northern California · 17 km W 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 38.3002, -122.6280. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Marin County, CA | 30 km (18 mi) | SSW | earthquakes near Marin County |
| Napa County, CA | 35 km (22 mi) | NE | earthquakes near Napa County |
| Sonoma County, CA | 36 km (22 mi) | NW | earthquakes near Sonoma County |
| Solano County, CA | 60 km (37 mi) | E | earthquakes near Solano County |
| Contra Costa County, CA | 73 km (45 mi) | SE | earthquakes near Contra Costa County |
| San Francisco County, CA | 73 km (45 mi) | SSW | earthquakes near San Francisco County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
44 earthquakes have been recorded within 50 km since this one.
- 1.5 12 km SE of Middletown, CA
- 2.3 12 km SE of Middletown, CA
- 1.5 12 km SE of Middletown, CA
- 1.6 12 km SE of Middletown, CA
- 1.8 8 km SW of Calistoga, CA
- 1.8 11 km E of Yountville, CA
- 2.2 1 km NW of Green Valley, CA
- 2.4 4 km W of Glen Ellen, CA
- 1.6 7 km WNW of Yountville, CA
- 1.8 3 km WNW of Boyes Hot Springs, CA
- 1.6 5 km NNE of Windsor, CA
- 2.3 8 km ENE of Kenwood, CA
- 1.8 6 km NE of Kenwood, CA
- 1.8 10 km ESE of Black Point-Green Point, CA
- 2.1 8 km WSW of Calistoga, 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.