18km SSW of San Miguel Is., CA

2023-05-30 10:50 UTC · 3.6 km deep · released about 16 lb of TNT

Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.

When: 2023-05-30 10:50 UTC
Magnitude: M 1.8 (ml)
Depth: 3.6 km below the surface
Felt: no reports yet
Nearest: Santa Barbara County, 82 km NNE
Status: Reviewed by a seismologist

USGS · last changed by USGS 1213 days ago · we first saw it 1213 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

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 5.8 930,000× the energy of this one
Magna, Utah 2020 M 5.7 660,000× the energy of this one
Around the size people start to feel M 3.0 59× 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.

Where

Map loads when it scrolls into view

Epicentre 33.8795, -120.4330. Map © OpenStreetMap contributors.

Nearby places

Place	Distance	Direction
Santa Barbara County, CA	82 km (51 mi)	SSW of here	earthquakes near Santa Barbara County

Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.

Aftershocks so far

7 earthquakes have been recorded within 50 km since this one.

1.6 24 km SSW of Santa Rosa Is., CA 22:41 UTC
2.6 15 km S of Santa Rosa Is., CA 23:44 UTC
2.5 16 km S of Santa Rosa Is., CA 00:14 UTC
2.2 23 km NW of Santa Cruz Is. (NW end), CA 09:11 UTC
2.3 22 km S of Santa Rosa Is., CA 19:54 UTC
3.2 23 km SSE of Santa Rosa Is., CA 14:43 UTC
2.0 15km SSW of San Miguel Is., CA 11:09 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 17:16 UTC. 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.