Earthquake near East Foothills, CA

A magnitude 3.3 earthquake was recorded 12 km (7 mi) ESE of East Foothills, CA, at 8:26 am PDT on 28 September 2016 (15:26 UTC). 53 people have reported feeling it to USGS. This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.

Earthquakes near other towns within 30 km: San Jose, Milpitas, Santa Clara, Morgan Hill, Campbell, Los Gatos.

How big was it?

This earthquake released about 1.1 tons of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 4.3 would have released about 32 times as much.

1. Northridge, California 1994 M 6.7 150,000× the energy of this one
2. Mineral, Virginia 2011 M 5.8 6,700× the energy of this one
3. Magna, Utah 2020 M 5.7 4,700× the energy of this one
4. This earthquake M 3.3 about 1.1 tons of TNT
5. Around the size people start to feel M 3.0 this one released 2.4× more

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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record lists 23 earthquakes of M5 or more within 50 km; the five largest:

1. 6.9 The 1989 Loma Prieta, California Earthquake · 37 km SSW of this epicentre Oct 18, 1989
2. 6.5 Near Morgan Hill, California · 26 km SSE of this epicentre Jul 1, 1911
3. 6.2 Near San Jose, California · 10 km WSW of this epicentre Aug 3, 1903
4. 6.2 The 1984 Morgan Hill, California Earthquake · 3 km SSE of this epicentre Apr 24, 1984
5. 6.1 Near San Jose, California · 18 km SSW of this epicentre Jun 11, 1903

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 37.3363, -121.6953. Map © OpenStreetMap contributors.

Nearby places

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

Aftershocks so far

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

1. 1.9 8 km NE of Gilroy, California 07:44 UTC
2. 2.0 14 km E of Seven Trees, California 02:14 UTC
3. 2.1 6 km ENE of East Foothills, California 16:01 UTC
4. 1.5 Northern California 22:32 UTC
5. 1.7 25 km SE of Livermore, California 19:27 UTC
6. 2.4 6 km NE of East Foothills, California 13:48 UTC
7. 2.1 15 km N of Morgan Hill, California 01:01 UTC
8. 1.7 3 km S of Loyola, California 20:24 UTC
9. 1.6 8 km ENE of Morgan Hill, California 11:36 UTC
10. 2.0 8 km E of East Foothills, California 15:05 UTC
11. 1.7 2 km S of Loyola, California 18:50 UTC
12. 2.3 8 km SE of Livermore, California 03:40 UTC
13. 1.7 6 km ESE of East Foothills, California 21:16 UTC
14. 2.3 7 km NNE of East Foothills, California 15:39 UTC
15. 1.8 1 km SSW of Loyola, California 18:45 UTC

Counted from the QuakeIndex database, which ingests the USGS feed every 30 seconds · as of 02:49 UTC. QuakeIndex does not forecast aftershocks. When USGS issues an operational aftershock forecast it appears on the USGS event page.

On USGS

• The official USGS event page — the source of record for every value above
• Did you feel it? Report it to USGS — reports go to USGS, not to us
• ShakeMap for this event, when USGS has produced one

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