QuakeIndex

Earthquake · reviewed by a seismologist

M 1.9md

Earthquake near Day Valley, CA

No earthquake was likely felt in Day Valley in the 24 hours to 7:28 pm PST (03:28 UTC). The last one was M 1.8, 10 km (6 mi) NNW, at 10:49 pm PDT on 29 October 2026, estimated intensity II (weak) in town. Every earthquake near Day Valley

This page: a magnitude 1.9 earthquake was recorded 5 km (3 mi) north-northwest of Day Valley, CA, at 5:16 am PDT on 9 June 2023 (12:16 UTC), 9.3 km deep.

USGS: 5km NNW of Day Valley, CA

25 km (16 mi) SSW of San Jose, CA · 17 km (11 mi) NE of Santa Cruz, CA

5:16 am PDT, Jun 9, 2023 · · 9.3 km deep · released about 25 lb of TNT

Every earthquake near Day Valley Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Santa Cruz County 13 kmSanta Clara County 24 kmSan Mateo County 57 kmAlameda County 63 kmSan Benito County 88 kmContra Costa County 94 kmStanislaus County 95 kmMerced County 104 kmMonterey County 106 km
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
5:16 am PDT on 9 June 2023 ()
Where
5 km (3 mi) north-northwest of Day Valley, CA · earthquakes near Day Valley
Magnitude
M 1.9 (md)
Depth
9.3 km below the surface
Felt
no reports yet
Nearest
Santa Cruz County, 13 km SW
Nearest mapped fault
San Andreas fault, 2 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 1251 days ago

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 12 km (7 mi) from the epicentre. In Day Valley, 5 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: Scotts Valley 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 25 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.0 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 600,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 420,000× the energy of this one
  3. Around the size people start to feel M 3.0 38× the energy of this one
  4. This earthquake M 1.9 about 25 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 2022-10-25 — about 46,000 times the energy of this one.

Before 2016, the USGS record lists 30 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.9 The 1989 Loma Prieta, California Earthquake · 5 km S of this epicentre
  2. 6.5 Near Morgan Hill, California · 22 km E of this epicentre
  3. 6.3 22 km S of Davenport, California · 41 km SW of this epicentre
  4. 6.3 16 km SW of Davenport, California · 44 km WSW of this epicentre
  5. 6.2 Near San Jose, California · 26 km NNE 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 37.0778, -121.8872. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Santa Cruz County, CA 13 km (8 mi) SW earthquakes near Santa Cruz County
Santa Clara County, CA 24 km (15 mi) NE earthquakes near Santa Clara County
San Mateo County, CA 57 km (35 mi) NW earthquakes near San Mateo County
Alameda County, CA 63 km (39 mi) N earthquakes near Alameda County
San Benito County, CA 88 km (55 mi) SE earthquakes near San Benito County
Contra Costa County, CA 94 km (58 mi) N earthquakes near Contra Costa County

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

Aftershocks so far

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

  1. 2.6 8 km NE of Gilroy, CA
  2. 2.1 4 km WSW of San Juan Bautista, CA
  3. 2.7 3 km ESE of Aromas, CA
  4. 1.6 4 km NNW of Aromas, CA
  5. 1.6 7 km SSE of Portola Valley, CA
  6. 1.7 12 km NNE of Alum Rock, CA
  7. 1.6 18 km SSW of Santa Cruz, CA
  8. 2.3 3 km ESE of Aromas, CA
  9. 1.6 6 km NE of San Juan Bautista, CA
  10. 2.8 3 km ESE of Aromas, CA
  11. 2.0 6 km SW of Gilroy, CA
  12. 2.5 10 km ENE of Morgan Hill, CA
  13. 2.4 11 km NNE of Alum Rock, CA
  14. 2.1 11 km NNE of Alum Rock, CA
  15. 2.5 14 km N of Morgan Hill, 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

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.