QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

9km NE of Morgan Hill, CA

· 2.3 km deep · released about 13 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Santa Clara County 11 kmSanta Cruz County 42 kmAlameda County 60 kmStanislaus County 66 kmSan Mateo County 75 kmMerced County 76 kmSan Benito County 77 kmSan Joaquin County 88 kmContra Costa County 88 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
Magnitude
M 1.8 (md)
Depth
2.3 km below the surface
Felt
no reports yet
Nearest
Santa Clara County, 11 km WNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1742 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

How big was it?

This earthquake released about 13 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.8 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,100,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 810,000× the energy of this one
  3. Around the size people start to feel M 3.0 72× the energy of this one
  4. This earthquake M 1.8 about 13 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.

Where

Epicentre 37.1818, -121.5797. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Santa Clara County, CA 11 km (7 mi) ESE of here earthquakes near Santa Clara County
Santa Cruz County, CA 42 km (26 mi) ENE of here earthquakes near Santa Cruz County
Alameda County, CA 60 km (37 mi) SSE of here earthquakes near Alameda County
Stanislaus County, CA 66 km (41 mi) SW of here earthquakes near Stanislaus County
San Mateo County, CA 75 km (46 mi) ESE of here earthquakes near San Mateo County
Merced County, CA 76 km (47 mi) W of here earthquakes near Merced County

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

Aftershocks so far

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

  1. 2.0 8km ENE of Milpitas, CA
  2. 1.7 16km SSE of Livermore, CA
  3. 1.7 9km ENE of Alum Rock, CA
  4. 1.5 8km ENE of Gilroy, CA
  5. 1.8 14km SE of Livermore, CA
  6. 1.7 7km WSW of Gilroy, CA
  7. 1.6 10km NNE of Alum Rock, CA
  8. 1.6 8km NNE of Milpitas, CA
  9. 1.8 19km SSE of Livermore, CA
  10. 1.6 23km WSW of Patterson, CA
  11. 1.6 4km W of San Juan Bautista, CA
  12. 1.9 3km WSW of Hollister, CA
  13. 2.7 5km SSW of Lexington Hills, CA
  14. 1.9 12km ESE of Alum Rock, CA
  15. 2.0 1km W of San Juan Bautista, 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.

For this area

The largest earthquake within 50 km in our catalogue was M 4.2 on 2021-01-17 — it released about 4,600 times the energy of this one.

From the QuakeIndex catalogue, built from the USGS FDSN event service.

On USGS

QuakeIndex does not issue warnings. For earthquake early warning see ShakeAlert.