Earthquake · reviewed by a seismologist
M 2.6md
Earthquake near Diablo, CA
No earthquake was likely felt in Diablo in the 24 hours to 5:15 am PST (13:15 UTC). The last one was M 2.5, 18 km (11 mi) NNW, at 1:23 am PST on 2 November 2026, estimated intensity II (weak) in town; 39 felt reports to USGS. Every earthquake near Diablo
This page: a magnitude 2.6 earthquake was recorded 5 km (3 mi) north-northwest of Diablo, CA, at 3:16 am PDT on 1 May 2018 (10:16 UTC), 5.7 km deep. 86 people have reported feeling it to USGS.
USGS: 5km NNW of Diablo, CA
6 km (4 mi) ESE of Walnut Creek, CA · 40 km (25 mi) ENE of San Francisco, CA
- When
- 3:16 am PDT on 1 May 2018 ()
- Where
- 5 km (3 mi) north-northwest of Diablo, CA · earthquakes near Diablo
- Magnitude
- M 2.6 (md)
- Depth
- 5.7 km below the surface
- Felt
- 86 reports · strongest reported intensity III
- Nearest
- Contra Costa County, 5 km NNE
- Nearest mapped fault
- Calaveras fault, 7 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 3112 days ago
Earthquake alerts for Diablo, 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 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 22 km (14 mi) from the epicentre. In Diablo, 5 km away, the estimate is intensity III (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: Alamo 6 km, intensity III · Danville 7 km, intensity III · Walnut Creek 8 km, intensity III · Pleasant Hill 10 km, intensity II · San Ramon 11 km, intensity II · Concord 12 km, intensity II · Lafayette 12 km, intensity II · Pacheco 14 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 220 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.6 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 70,000× the energy of this one
- Magna, Utah 2020 M 5.7 50,000× the energy of this one
- Around the size people start to feel M 3.0 4.4× the energy of this one
- This earthquake M 2.6 about 220 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 2018-01-04 — about 520 times the energy of this one.
Before 2016, the USGS record lists 5 earthquakes of M5 or more within 50 km:
- 6.0 The 2014 South Napa, California Earthquake · 47 km NW of this epicentre
- 5.8 The 1980 Livermore, California Earthquake · 19 km ESE of this epicentre
- 5.4 South of Elmira, California · 47 km N of this epicentre
- 5.4 9 km NE of Livermore, California · 28 km ESE of this epicentre
- 5.1 11 km E of Blackhawk, California · 20 km ESE 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 37.8805, -121.9797. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Contra Costa County, CA | 5 km (3 mi) | NNE | earthquakes near Contra Costa County |
| Alameda County, CA | 27 km (17 mi) | SSE | earthquakes near Alameda County |
| Solano County, CA | 43 km (27 mi) | N | earthquakes near Solano County |
| San Mateo County, CA | 62 km (39 mi) | SW | earthquakes near San Mateo County |
| San Joaquin County, CA | 62 km (39 mi) | E | earthquakes near San Joaquin County |
| Marin County, CA | 70 km (43 mi) | WNW | earthquakes near Marin County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
59 earthquakes have been recorded within 50 km since this one.
- 2.9 12km SE of Suisun City, CA
- 2.9 15km ESE of Suisun City, CA
- 2.2 8km SE of Suisun City, CA
- 1.9 10km ESE of Black Point-Green Point, CA
- 3.7 10km ESE of Black Point-Green Point, CA
- 1.8 8km SE of Suisun City, CA
- 1.6 14km ENE of Milpitas, CA
- 1.5 5km NNE of Fremont, CA
- 1.8 3km E of Hayward, CA
- 1.9 3km NNE of Bay Point, CA
- 1.6 3km NW of Castro Valley, CA
- 2.9 2km NW of Castro Valley, CA
- 1.6 8km SSW of Brentwood, CA
- 1.9 7km SSW of Brentwood, CA
- 1.7 2km SE of Danville, 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.