QuakeIndex

Earthquake · reviewed by a seismologist

M 1.8md

10km ENE of Morgan Hill, CA

· 4.7 km deep · released about 17 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Santa Clara County 14 kmSanta Cruz County 44 kmAlameda County 63 kmStanislaus County 66 kmMerced County 74 kmSan Benito County 74 kmSan Mateo County 78 kmSan Joaquin County 89 kmContra Costa County 91 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
4.7 km below the surface
Felt
no reports yet
Nearest
Santa Clara County, 14 km WNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 1592 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 17 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 5.8 870,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 620,000× the energy of this one
  3. Around the size people start to feel M 3.0 55× the energy of this one
  4. This earthquake M 1.8 about 17 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 37.1630, -121.5528. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Santa Clara County, CA 14 km (9 mi) ESE of here earthquakes near Santa Clara County
Santa Cruz County, CA 44 km (27 mi) ENE of here earthquakes near Santa Cruz County
Alameda County, CA 63 km (39 mi) SSE of here earthquakes near Alameda County
Stanislaus County, CA 66 km (41 mi) SW of here earthquakes near Stanislaus County
Merced County, CA 74 km (46 mi) W of here earthquakes near Merced County
San Benito County, CA 74 km (46 mi) NW of here earthquakes near San Benito County

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

Aftershocks so far

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

  1. 1.7 2km E of Aromas, CA
  2. 2.2 9km NE of Milpitas, CA
  3. 2.2 4km SSW of San Juan Bautista, CA
  4. 1.5 2km E of Aromas, CA
  5. 1.7 2km SW of Hollister, CA
  6. 1.8 11km NE of Milpitas, CA
  7. 1.6 2km ENE of Aromas, CA
  8. 2.2 1km ENE of Hollister, CA
  9. 1.8 7km NE of Ridgemark, CA
  10. 1.5 7km NE of Ridgemark, CA
  11. 1.9 13km ESE of Alum Rock, CA
  12. 1.8 5km WSW of Ridgemark, CA
  13. 3.0 10km ESE of Gilroy, CA
  14. 1.9 9km NE of Milpitas, CA
  15. 1.9 4km S 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 3,500 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.