QuakeIndex

Earthquake · reviewed by a seismologist

M 2.9ml

Earthquake near Ridgemark, CA

Yes: an earthquake was likely felt in Ridgemark in the last 24 hours. M 1.6, 11 km (7 mi) S of Ridgemark, at 11:35 pm PST on 11 November 2026 (07:35 UTC); the estimated shaking in Ridgemark was intensity II (weak). Every earthquake near Ridgemark

This page: a magnitude 2.9 earthquake was recorded 11 km (7 mi) southwest of Ridgemark, CA, at 3:55 pm PDT on 6 July 2020 (22:55 UTC), 7.0 km deep. 27 people have reported feeling it to USGS.

USGS: 11km SW of Ridgemark, CA

69 km (43 mi) SSE of San Jose, CA · 17 km (11 mi) ENE of Salinas, CA

3:55 pm PDT, Jul 6, 2020 · · 7.0 km deep · released about 630 lb of TNT

10 km30 km60 km120 km N San Benito County 36 kmSanta Clara County 57 kmSanta Cruz County 57 kmMonterey County 58 kmMerced County 82 kmStanislaus County 99 kmAlameda County 108 kmSan Mateo County 110 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
3:55 pm PDT on 6 July 2020 ()
Where
11 km (7 mi) southwest of Ridgemark, CA · earthquakes near Ridgemark
Magnitude
M 2.9 (ml)
Depth
7.0 km below the surface
Felt
27 reports · strongest reported intensity III
Nearest
San Benito County, 36 km ESE
Nearest mapped fault
San Andreas fault, 4 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 2253 days ago

This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

At this magnitude and depth, people at rest would likely notice it out to about 30 km (19 mi) from the epicentre. In Ridgemark, 11 km away, the estimate is intensity III (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: Hollister 13 km, intensity III · Prunedale 19 km, intensity II · Salinas 19 km, intensity II · Gilroy 30 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 630 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 3.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 24,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 17,000× the energy of this one
  3. Around the size people start to feel M 3.0 1.5× the energy of this one
  4. This earthquake M 2.9 about 630 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 560 times the energy of this one.

Before 2016, the USGS record lists 25 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.9 The 1989 Loma Prieta, California Earthquake · 50 km NW of this epicentre
  2. 6.5 Near Morgan Hill, California · 43 km NNW of this epicentre
  3. 5.9 10 km SE of Tres Pinos, California · 21 km E of this epicentre
  4. 5.8 Near Watsonville, California · 31 km NW of this epicentre
  5. 5.8 Near Paicines, California · 20 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 36.7478, -121.4557. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
San Benito County, CA 36 km (23 mi) ESE earthquakes near San Benito County
Santa Clara County, CA 57 km (35 mi) NNW earthquakes near Santa Clara County
Santa Cruz County, CA 57 km (36 mi) WNW earthquakes near Santa Cruz County
Monterey County, CA 58 km (36 mi) SSE earthquakes near Monterey County
Merced County, CA 82 km (51 mi) NE earthquakes near Merced County
Stanislaus County, CA 99 km (62 mi) NNE earthquakes near Stanislaus County

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

Aftershocks so far

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

  1. 2.2 5km ENE of Pinnacles, CA
  2. 2.0 4km ESE of Aromas, CA
  3. 2.3 16km SSE of Tres Pinos, CA
  4. 2.3 2km NE of Pinnacles, CA
  5. 2.5 2km ENE of Aromas, CA
  6. 1.7 9km NE of San Martin, CA
  7. 2.0 24km WSW of Los Banos, CA
  8. 1.7 9km SSE of San Juan Bautista, CA
  9. 1.8 7km SSW of Gonzales, CA
  10. 1.6 9km NNE of Gonzales, CA
  11. 1.6 12km SE of Pinnacles, CA
  12. 2.6 10km SE of Pinnacles, CA
  13. 2.0 3km N of Hollister, CA
  14. 2.3 4km ESE of Aromas, CA
  15. 2.8 3km ESE 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.