quarry blast · reviewed by a seismologist
M 1.7md
Earthquake near Felton, CA
No earthquake was likely felt in Felton in the 24 hours to 2:50 pm PST (22:50 UTC). The last one was M 2.3, 12 km (7 mi) NE, at 2:58 am PDT on 9 October 2026, estimated intensity II (weak) in town; 3 felt reports to USGS. Every earthquake near Felton
No: USGS classifies this as a quarry blast, not an earthquake. A magnitude 1.7 quarry blast was recorded 4 km (2 mi) southwest of Felton, CA, at 1:01 pm PDT on 7 June 2023 (20:01 UTC), less than 1 km deep.
USGS: 4km SW of Felton, CA
9 km (5 mi) NW of Santa Cruz, CA · 39 km (25 mi) SW of San Jose, CA
- When
- 1:01 pm PDT on 7 June 2023 ()
- Where
- 4 km (2 mi) southwest of Felton, CA · earthquakes near Felton
- Magnitude
- M 1.7 (md)
- Depth
- -0.4 km below the surface
- Felt
- no reports yet
- Nearest
- Santa Cruz County, 9 km E
- Nearest mapped fault
- Monterey Bay- Tularcitos 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 1253 days ago
Earthquake alerts for Felton, CA
Get a notification in this browser when USGS records an earthquake near Felton, CA. No account or email needed.
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 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 13 km (8 mi) from the epicentre. In Felton, 4 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 8 km, intensity II · Santa Cruz 9 km, intensity II · Boulder Creek 11 km, intensity II · Live Oak 12 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 12 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 1,200,000× the energy of this one
- Magna, Utah 2020 M 5.7 870,000× the energy of this one
- Around the size people start to feel M 3.0 78× the energy of this one
- This earthquake M 1.7 about 12 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 95,000 times the energy of this one.
Before 2016, the USGS record lists 24 earthquakes of M5 or more within 50 km; the five largest:
- 6.9 The 1989 Loma Prieta, California Earthquake · 20 km E of this epicentre
- 6.5 Near Morgan Hill, California · 43 km ENE of this epicentre
- 6.3 22 km S of Davenport, California · 26 km SSW of this epicentre
- 6.3 16 km SW of Davenport, California · 24 km WSW of this epicentre
- 6.2 Near San Jose, California · 41 km NE 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 37.0277, -122.1055. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Santa Cruz County, CA | 9 km (5 mi) | E | earthquakes near Santa Cruz County |
| Santa Clara County, CA | 43 km (27 mi) | ENE | earthquakes near Santa Clara County |
| San Mateo County, CA | 49 km (30 mi) | NNW | earthquakes near San Mateo County |
| Alameda County, CA | 71 km (44 mi) | NNE | earthquakes near Alameda County |
| Contra Costa County, CA | 100 km (62 mi) | N | earthquakes near Contra Costa County |
| San Benito County, CA | 102 km (63 mi) | ESE | earthquakes near San Benito County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
39 earthquakes have been recorded within 50 km since this one.
- 1.6 5 km WSW of Cupertino, CA
- 1.9 4 km WSW of Cupertino, CA
- 2.9 4 km WSW of Cupertino, CA
- 1.6 2 km ENE of Aromas, CA
- 1.7 6 km SSW of Gilroy, CA
- 1.6 13 km SSW of Bonny Doon, CA
- 1.6 9 km SW of Loyola, CA
- 1.9 8 km WSW of Gilroy, CA
- 2.0 7 km N of Aromas, CA
- 1.6 1 km E of Aromas, CA
- 1.6 7 km SSE of Portola Valley, CA
- 2.7 3 km ESE of Aromas, CA
- 1.6 4 km NNW of Aromas, CA
- 1.6 7 km SSE of Portola Valley, CA
- 1.6 18 km SSW of Santa Cruz, 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.