QuakeIndex

quarry blast · reviewed by a seismologist

M 1.8md

2 km E of Aromas, California

· -0.1 km deep · released about 15 lb of TNT

Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Santa Cruz County 37 kmSanta Clara County 38 kmSan Benito County 56 kmMonterey County 77 kmMerced County 87 kmAlameda County 88 kmSan Mateo County 89 kmStanislaus County 93 kmContra Costa County 119 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
-0.1 km below the surface
Felt
1 report · strongest reported intensity II
Nearest
Santa Cruz County, 37 km WNW
Status
Reviewed by a seismologist

USGS · last changed by USGS · we first saw it 3515 days ago

This was a minor earthquake. Quakes this small are rarely felt and do not cause damage. 1 person has reported feeling it to USGS.

USGS catalogues this as quarry blast, not an earthquake.

How big was it?

This earthquake released about 15 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 1,000,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 730,000× the energy of this one
  3. Around the size people start to feel M 3.0 65× the energy of this one
  4. This earthquake M 1.8 about 15 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 36.8865, -121.6187. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection
Santa Cruz County, CA 37 km (23 mi) ESE of here earthquakes near Santa Cruz County
Santa Clara County, CA 38 km (23 mi) S of here earthquakes near Santa Clara County
San Benito County, CA 56 km (35 mi) WNW of here earthquakes near San Benito County
Monterey County, CA 77 km (48 mi) NNW of here earthquakes near Monterey County
Merced County, CA 87 km (54 mi) WSW of here earthquakes near Merced County
Alameda County, CA 88 km (55 mi) SSE of here earthquakes near Alameda County

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

Aftershocks so far

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

  1. 2.3 5 km SSW of Gilroy, California
  2. 2.9 14 km N of Morgan Hill, California
  3. 2.2 3 km S of San Juan Bautista, California
  4. 1.9 5 km S of Gilroy, California
  5. 1.6 16 km E of Seven Trees, California
  6. 1.6 5 km S of Gilroy, California
  7. 3.4 3 km S of San Juan Bautista, California
  8. 3.6 5 km S of Gilroy, California
  9. 1.5 5 km SW of Gilroy, California
  10. 1.9 15 km SSE of Tres Pinos, California
  11. 1.9 8 km ENE of San Martin, California
  12. 1.9 15 km SSE of Tres Pinos, California
  13. 2.3 9 km S of Tres Pinos, California
  14. 2.0 8 km SSE of San Juan Bautista, California
  15. 2.0 4 km SSE of San Juan Bautista, California

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 2016-07-19 — it released about 4,400 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.