QuakeIndex

quarry blast · reviewed by a seismologist

M 1.5md

Earthquake near Prunedale, CA

No earthquake was likely felt in Prunedale in the 24 hours to 4:37 am PST (12:37 UTC). The last one was M 2.0, 11 km (7 mi) ENE, at 2:11 am PST on 11 November 2026, estimated intensity II (weak) in town. Every earthquake near Prunedale

No: USGS classifies this as a quarry blast, not an earthquake. A magnitude 1.5 quarry blast was recorded 7 km (4 mi) east-southeast of Prunedale, CA, at 1:12 pm PDT on 9 October 2024 (20:12 UTC), less than 1 km deep. 1 person has reported feeling it to USGS.

USGS: 7 km SE of Prunedale, CA

7 km (4 mi) NNE of Salinas, CA

1:12 pm PDT, Oct 9, 2024 · · -0.1 km deep · released about 5.4 lb of TNT

10 km30 km60 km120 km N Santa Cruz County 47 kmSan Benito County 48 kmSanta Clara County 53 kmMonterey County 62 kmMerced County 92 kmSan Mateo County 101 kmAlameda County 104 kmStanislaus County 105 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
1:12 pm PDT on 9 October 2024 ()
Where
7 km (4 mi) east-southeast of Prunedale, CA · earthquakes near Prunedale
Magnitude
M 1.5 (md)
Depth
-0.1 km below the surface
Felt
1 report · strongest reported intensity II
Nearest
Santa Cruz County, 47 km NW
Nearest mapped fault
Zayante-Vergeles fault, 8 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 763 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 10 km (6 mi) from the epicentre. In Prunedale, 7 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: Prunedale 7 km, intensity II · Salinas 9 km, intensity II. Estimated for each town centre; each link is that town's own record.

USGS catalogues this as quarry blast, not an earthquake.

How big was it?

This earthquake released about 5.4 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.

  1. Mineral, Virginia 2011 M 5.8 2,800,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 2,000,000× the energy of this one
  3. Around the size people start to feel M 3.0 180× the energy of this one
  4. This earthquake M 1.5 about 5.4 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 4.7 on 2019-10-15 — about 65,000 times the energy of this one.

Before 2016, the USGS record lists 28 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.9 The 1989 Loma Prieta, California Earthquake · 41 km NW of this epicentre
  2. 6.5 Near Morgan Hill, California · 41 km N of this epicentre
  3. 5.9 10 km SE of Tres Pinos, California · 33 km E of this epicentre
  4. 5.8 Near Watsonville, California · 24 km NNW of this epicentre
  5. 5.8 Near Paicines, California · 32 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 36.7472, -121.5973. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Santa Cruz County, CA 47 km (29 mi) NW earthquakes near Santa Cruz County
San Benito County, CA 48 km (30 mi) ESE earthquakes near San Benito County
Santa Clara County, CA 53 km (33 mi) N earthquakes near Santa Clara County
Monterey County, CA 62 km (38 mi) SSE earthquakes near Monterey County
Merced County, CA 92 km (57 mi) ENE earthquakes near Merced County
San Mateo County, CA 101 km (63 mi) NW earthquakes near San Mateo County

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

Aftershocks so far

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

  1. 1.7 17 km S of Tres Pinos, CA
  2. 1.7 6 km SSW of Gilroy, CA
  3. 2.3 16 km S of Tres Pinos, CA
  4. 3.0 8 km S of Tres Pinos, CA
  5. 2.1 3 km NNW of Pinnacles, CA
  6. 2.3 3 km N of Tres Pinos, CA
  7. 1.8 2 km ENE of Pinnacles, CA
  8. 1.6 2 km NE of Pinnacles, CA
  9. 1.7 5 km NW of Hollister, CA
  10. 1.6 15 km NNW of Pinnacles, CA
  11. 1.6 17 km NW of Pinnacles, CA
  12. 1.7 4 km SSW of San Juan Bautista, CA
  13. 1.9 6 km NNW of Pinnacles, CA
  14. 1.7 6 km SW of Gilroy, CA
  15. 2.2 2 km E of Aromas, 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.