QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6md

Earthquake near Bonny Doon, CA

No earthquake was likely felt in Bonny Doon in the 24 hours to 9:19 pm PST (05:19 UTC). The last one was M 3.8, 79 km (49 mi) N, at 8:30 am PDT on 13 August 2026, estimated intensity II (weak) in town; 7,876 felt reports to USGS. Every earthquake near Bonny Doon

This page: a magnitude 1.6 earthquake was recorded 13 km (8 mi) south-southwest of Bonny Doon, CA, at 6:36 am PDT on 3 September 2023 (13:36 UTC), 5.9 km deep.

USGS: 13 km SSW of Bonny Doon, CA

54 km (33 mi) SW of San Jose, CA · 16 km (10 mi) WSW of Santa Cruz, CA

6:36 am PDT, Sep 3, 2023 · · 5.9 km deep · released about 7.8 lb of TNT

Every earthquake near Bonny Doon Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Santa Cruz County 20 kmSan Mateo County 56 kmSanta Clara County 56 kmAlameda County 84 kmSan Benito County 106 kmMonterey County 111 kmContra Costa County 112 kmSan Francisco County 115 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
6:36 am PDT on 3 September 2023 ()
Where
13 km (8 mi) south-southwest of Bonny Doon, CA · earthquakes near Bonny Doon
Magnitude
M 1.6 (md)
Depth
5.9 km below the surface
Felt
no reports yet
Nearest
Santa Cruz County, 20 km ENE
Nearest mapped fault
San Gregorio fault, under 1 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 1162 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 Bonny Doon, 13 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.

Earthquakes near other towns within 30 km: Santa Cruz, Felton, Pasatiempo, Mount Hermon, Twin Lakes, Ben Lomond.

How big was it?

This earthquake released about 7.8 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.6 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,900,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,400,000× the energy of this one
  3. Around the size people start to feel M 3.0 120× the energy of this one
  4. This earthquake M 1.6 about 7.8 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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record lists 19 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.9 The 1989 Loma Prieta, California Earthquake · 31 km ENE of this epicentre
  2. 6.3 22 km S of Davenport, California · 14 km S of this epicentre
  3. 6.3 16 km SW of Davenport, California · 12 km W of this epicentre
  4. 6.1 Near San Jose, California · 47 km NE of this epicentre
  5. 5.8 Near Watsonville, California · 45 km E 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 36.9302, -122.2082. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Santa Cruz County, CA 20 km (12 mi) ENE earthquakes near Santa Cruz County
San Mateo County, CA 56 km (35 mi) NNW earthquakes near San Mateo County
Santa Clara County, CA 56 km (35 mi) NE earthquakes near Santa Clara County
Alameda County, CA 84 km (52 mi) NNE earthquakes near Alameda County
San Benito County, CA 106 km (66 mi) ESE earthquakes near San Benito County
Monterey County, CA 111 km (69 mi) SE earthquakes near Monterey County

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

Aftershocks so far

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

  1. 2.1 14 km WSW of Santa Cruz, CA
  2. 1.5 11 km WSW of Bonny Doon, CA
  3. 1.5 4 km ESE of Interlaken, CA
  4. 1.7 0 km SW of Day Valley, CA
  5. 1.5 4 km NNW of Aromas, CA
  6. 1.8 5 km of Aromas, CA
  7. 2.1 22 km WNW of Boulder Creek, CA
  8. 1.6 4 km NNE of Day Valley, CA
  9. 1.9 4 km NNE of Day Valley, CA
  10. 2.1 4 km NNE of Day Valley, CA
  11. 2.4 4 km NNE of Day Valley, CA
  12. 1.6 7 km N of Day Valley, CA
  13. 1.6 15 km SSW of Bonny Doon, CA
  14. 1.8 16 km WSW of Bonny Doon, CA
  15. 1.7 5 km ESE of Interlaken, 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.