QuakeIndex

quarry blast · reviewed by a seismologist

M 1.7md

Earthquake near Aromas, CA

USGS: 2 km E of Aromas, California

13 km (8 mi) SSW of Gilroy, CA · 48 km (30 mi) SSE of San Jose, CA

3:44 pm PDT, Aug 23, 2016 · · -0.1 km deep · released about 11 lb of TNT

Every earthquake near Aromas Felt it? Tell USGS Check my area
10 km30 km60 km120 km N Santa Clara County 37 kmSanta Cruz County 37 kmSan Benito County 56 kmMonterey County 77 kmMerced County 86 kmAlameda County 88 kmSan Mateo County 89 kmStanislaus County 92 kmContra Costa County 118 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
3:44 pm PDT on 23 August 2016 ()
Where
3 km (2 mi) E of Aromas, CA · earthquakes near Aromas
Magnitude
M 1.7 (md)
Depth
-0.1 km below the surface
Felt
no reports yet
Nearest
Santa Clara County, 37 km N
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 3521 days ago

A magnitude 1.7 earthquake was recorded 3 km (2 mi) E of Aromas, CA, at 3:44 pm PDT on 23 August 2016 (22:44 UTC). This was a minor earthquake. Quakes this small are rarely felt and do not cause damage.

Earthquakes near other towns within 30 km: San Juan Bautista, Las Lomas, Pajaro, Interlaken, Watsonville, Gilroy.

USGS catalogues this as quarry blast, not an earthquake.

How big was it?

This earthquake released about 11 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.7 would have released about 32 times as much.

  1. Mineral, Virginia 2011 M 5.8 1,300,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 930,000× the energy of this one
  3. Around the size people start to feel M 3.0 83× the energy of this one
  4. This earthquake M 1.7 about 11 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 4.2 on 2016-07-19 — about 5,600 times the energy of this one.

Before 2016, the USGS record lists 30 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.9 The 1989 Loma Prieta, California Earthquake · 29 km NW of this epicentre
  2. 6.5 Near Morgan Hill, California · 25 km N of this epicentre
  3. 6.2 Near San Jose, California · 48 km NNW of this epicentre
  4. 6.2 The 1984 Morgan Hill, California Earthquake · 47 km N of this epicentre
  5. 6.1 Near San Jose, California · 38 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 36.8913, -121.6143. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Santa Clara County, CA 37 km (23 mi) N earthquakes near Santa Clara County
Santa Cruz County, CA 37 km (23 mi) WNW earthquakes near Santa Cruz County
San Benito County, CA 56 km (35 mi) ESE earthquakes near San Benito County
Monterey County, CA 77 km (48 mi) SSE earthquakes near Monterey County
Merced County, CA 86 km (53 mi) ENE earthquakes near Merced County
Alameda County, CA 88 km (55 mi) NNW earthquakes near Alameda County

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

Aftershocks so far

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

  1. 2.0 Central California
  2. 2.1 9 km SSW of Tres Pinos, California
  3. 2.8 17 km SSE of Tres Pinos, California
  4. 1.8 11 km ESE of East Foothills, California
  5. 1.5 11 km ESE of East Foothills, California
  6. 1.8 5 km SW of Gilroy, California
  7. 2.0 20 km SSE of Tres Pinos, California
  8. 1.6 20 km SSE of Tres Pinos, California
  9. 2.1 7 km WSW of Ridgemark, California
  10. 2.1 7 km SW of Ridgemark, California
  11. 1.8 2 km WSW of San Juan Bautista, California
  12. 1.9 15 km SE of Tres Pinos, California
  13. 1.5 0 km W of Hollister, California
  14. 2.1 11 km ESE of East Foothills, California
  15. 1.5 2 km WNW of Ridgemark, 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.

On USGS

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