QuakeIndex

Earthquake · reviewed by a seismologist

M 1.6md

Earthquake near Loyola, CA

No earthquake was likely felt in Loyola in the 24 hours to 2:09 pm PST (22:09 UTC). The last one was M 2.0, 5 km (3 mi) SSE, at 9:23 am PST on 10 November 2026, estimated intensity II (weak) in town; 4 felt reports to USGS. Every earthquake near Loyola

This page: a magnitude 1.6 earthquake was recorded 9 km (5 mi) southwest of Loyola, CA, at 7:45 am PDT on 2 September 2023 (14:45 UTC), 6.6 km deep.

USGS: 9 km SW of Loyola, CA

11 km (7 mi) WSW of Cupertino, CA · 31 km (20 mi) W of San Jose, CA

7:45 am PDT, Sep 2, 2023 · · 6.6 km deep · released about 8.4 lb of TNT

Every earthquake near Loyola Felt it? Tell USGS Check my area
10 km30 km60 km120 km N San Mateo County 22 kmSanta Cruz County 35 kmSanta Clara County 43 kmAlameda County 45 kmContra Costa County 72 kmSan Francisco County 90 kmMarin County 98 kmSan Joaquin County 106 kmStanislaus County 107 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
7:45 am PDT on 2 September 2023 ()
Where
9 km (5 mi) southwest of Loyola, CA · earthquakes near Loyola
Magnitude
M 1.6 (md)
Depth
6.6 km below the surface
Felt
no reports yet
Nearest
San Mateo County, 22 km NW
Nearest mapped fault
San Andreas fault, 2 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 9 km (6 mi) from the epicentre. In Loyola, 9 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: Los Altos Hills, Los Altos, Portola Valley, Ladera, Mountain View, Cupertino.

How big was it?

This earthquake released about 8.4 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 1,800,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,300,000× the energy of this one
  3. Around the size people start to feel M 3.0 110× the energy of this one
  4. This earthquake M 1.6 about 8.4 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 5.1 on 2022-10-25 — about 140,000 times the energy of this one.

Before 2016, the USGS record lists 18 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.9 The 1989 Loma Prieta, California Earthquake · 39 km SE of this epicentre
  2. 6.3 16 km SW of Davenport, California · 44 km SSW of this epicentre
  3. 6.2 Near San Jose, California · 33 km E of this epicentre
  4. 6.2 The 1984 Morgan Hill, California Earthquake · 43 km E of this epicentre
  5. 6.1 Near San Jose, California · 34 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 37.2965, -122.1700. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
San Mateo County, CA 22 km (14 mi) NW earthquakes near San Mateo County
Santa Cruz County, CA 35 km (22 mi) SSE earthquakes near Santa Cruz County
Santa Clara County, CA 43 km (27 mi) E earthquakes near Santa Clara County
Alameda County, CA 45 km (28 mi) NNE earthquakes near Alameda County
Contra Costa County, CA 72 km (45 mi) NNE earthquakes near Contra Costa County
San Francisco County, CA 90 km (56 mi) WNW earthquakes near San Francisco County

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

Aftershocks so far

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

  1. 1.5 2 km ESE of Pacifica, CA
  2. 1.7 2 km NNE of Saratoga, CA
  3. 1.6 4 km SW of Hillsborough, CA
  4. 1.7 9 km NNE of Alum Rock, CA
  5. 1.6 4 km SW of Hillsborough, CA
  6. 1.5 2 km NNE of Millbrae, CA
  7. 2.1 10 km SE of Sunol, CA
  8. 1.5 8 km SSW of Livermore, CA
  9. 1.5 3 km NNE of Millbrae, CA
  10. 1.7 2 km ENE of Pacifica, CA
  11. 1.5 6 km NNE of Alum Rock, CA
  12. 1.6 3 km NNE of Millbrae, CA
  13. 2.0 14 km ESE of Alum Rock, CA
  14. 1.6 2 km ENE of San Leandro, CA
  15. 1.6 8 km NNE of Milpitas, 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.