QuakeIndex

Earthquake · reviewed by a seismologist

M 1.9md

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 1.9 earthquake was recorded 6 km (3 mi) south-southwest of Ridgemark, CA, at 7:25 pm PST on 21 January 2020 (03:25 UTC), 5.4 km deep.

USGS: 6km SSW of Ridgemark, CA

70 km (43 mi) SSE of San Jose, CA · 23 km (14 mi) ENE of Salinas, CA

7:25 pm PST, Jan 21, 2020 · · 5.4 km deep · released about 18 lb of TNT

10 km30 km60 km120 km N San Benito County 32 kmSanta Clara County 57 kmMonterey County 59 kmSanta Cruz County 61 kmMerced County 76 kmStanislaus County 95 kmAlameda County 108 kmSan Mateo County 113 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
7:25 pm PST on 21 January 2020 ()
Where
6 km (3 mi) south-southwest of Ridgemark, CA · earthquakes near Ridgemark
Magnitude
M 1.9 (md)
Depth
5.4 km below the surface
Felt
no reports yet
Nearest
San Benito County, 32 km ESE
Nearest mapped fault
San Andreas fault, 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 2477 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 13 km (8 mi) from the epicentre. In Ridgemark, 6 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: Hollister 10 km, intensity II. Estimated for each town centre; each link is that town's own record.

How big was it?

This earthquake released about 18 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 840,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 600,000× the energy of this one
  3. Around the size people start to feel M 3.0 53× the energy of this one
  4. This earthquake M 1.9 about 18 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 19,000 times the energy of this one.

Before 2016, the USGS record lists 24 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.5 Near Morgan Hill, California · 44 km NNW of this epicentre
  2. 5.9 10 km SE of Tres Pinos, California · 16 km ESE of this epicentre
  3. 5.8 Near Watsonville, California · 34 km NW of this epicentre
  4. 5.8 Near Paicines, California · 17 km SE of this epicentre
  5. 5.8 The 1979 Coyote Lake, California Earthquake · 39 km NNW 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 36.7670, -121.3920. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
San Benito County, CA 32 km (20 mi) ESE earthquakes near San Benito County
Santa Clara County, CA 57 km (35 mi) NNW earthquakes near Santa Clara County
Monterey County, CA 59 km (37 mi) S earthquakes near Monterey County
Santa Cruz County, CA 61 km (38 mi) WNW earthquakes near Santa Cruz County
Merced County, CA 76 km (47 mi) NE earthquakes near Merced County
Stanislaus County, CA 95 km (59 mi) NNE earthquakes near Stanislaus County

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

Aftershocks so far

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

  1. 2.9 2km NE of Pinnacles, CA
  2. 1.6 8km NNW of Pinnacles, CA
  3. 2.0 3km W of San Juan Bautista, CA
  4. 1.9 7km NNW of Pinnacles, CA
  5. 1.6 12km E of Pinnacles, CA
  6. 2.1 10km S of Tres Pinos, CA
  7. 1.7 3km E of Aromas, CA
  8. 2.1 13km NW of Pinnacles, CA
  9. 1.6 8km NE of Gilroy, CA
  10. 2.4 9km SSW of Tres Pinos, CA
  11. 2.5 7km NNW of Pinnacles, CA
  12. 1.6 4km NNW of Pinnacles, CA
  13. 1.5 6km NW of Pinnacles, CA
  14. 1.5 12km NW of Pinnacles, CA
  15. 2.1 5km SE of Tres Pinos, 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.