Earthquake · reviewed by a seismologist
M 3.3ml
Earthquake near Morgan Hill, CA
No earthquake was likely felt in Morgan Hill in the 24 hours to 2:44 pm PST (22:44 UTC). The last one was M 2.6, 20 km (13 mi) N, at 12:38 pm PDT on 27 October 2026, estimated intensity II (weak) in town; 8 felt reports to USGS. Every earthquake near Morgan Hill
This page: a magnitude 3.3 earthquake was recorded 10 km (6 mi) northeast of Morgan Hill, CA, at 1:32 am PDT on 12 September 2023 (08:32 UTC), 5.8 km deep. 327 people have reported feeling it to USGS.
USGS: 10 km NE of Morgan Hill, CA
25 km (15 mi) ESE of San Jose, CA · 20 km (13 mi) N of Gilroy, CA
- When
- 1:32 am PDT on 12 September 2023 ()
- Where
- 10 km (6 mi) northeast of Morgan Hill, CA · earthquakes near Morgan Hill
- Magnitude
- M 3.3 (ml)
- Depth
- 5.8 km below the surface
- Felt
- 327 reports · strongest reported intensity III
- Nearest
- Santa Clara County, 11 km WNW
- Nearest mapped fault
- Calaveras fault, 4 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 224 days ago
Earthquake alerts for Morgan Hill, CA
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Alerts are on for .
Not a warning. An alert comes after USGS publishes a quake, usually minutes after the shaking. For early warning use ShakeAlert, through your phone's Wireless Emergency Alerts or the MyShake app.
This was a small earthquake. Shaking like this is often felt indoors nearby and very rarely causes damage.
At this magnitude and depth, people at rest would likely notice it out to about 51 km (32 mi) from the epicentre. In Morgan Hill, 10 km away, the estimate is intensity III (weak). Estimated from magnitude, depth and distance with the intensity equation USGS Did You Feel It? uses; felt reports, where there are any, are the measurement.
Likely felt in: Morgan Hill 10 km, intensity III · Gilroy 20 km, intensity III · San Jose 33 km, intensity II · Watsonville 35 km, intensity II · Campbell 35 km, intensity II · Los Gatos 36 km, intensity II · Santa Clara 39 km, intensity II · Milpitas 40 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 1.3 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.
- Northridge, California 1994 M 6.7 130,000× the energy of this one
- Mineral, Virginia 2011 M 5.8 6,000× the energy of this one
- Magna, Utah 2020 M 5.7 4,300× the energy of this one
- This earthquake M 3.3 about 1.3 tons of TNT
- Around the size people start to feel M 3.0 this one released 2.6× 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
The largest earthquake within 50 km since 2016 was M 5.1 on 2022-10-25 — about 470 times the energy of this one.
Before 2016, the USGS record lists 28 earthquakes of M5 or more within 50 km; the five largest:
- 6.9 The 1989 Loma Prieta, California Earthquake · 32 km WSW of this epicentre
- 6.5 Near Morgan Hill, California · 10 km SSW of this epicentre
- 6.2 Near San Jose, California · 24 km WNW of this epicentre
- 6.2 The 1984 Morgan Hill, California Earthquake · 17 km NW of this epicentre
- 6.1 Near San Jose, California · 20 km W 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 37.1875, -121.5730. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Santa Clara County, CA | 11 km (7 mi) | WNW | earthquakes near Santa Clara County |
| Santa Cruz County, CA | 43 km (27 mi) | WSW | earthquakes near Santa Cruz County |
| Alameda County, CA | 59 km (37 mi) | NNW | earthquakes near Alameda County |
| Stanislaus County, CA | 65 km (41 mi) | NE | earthquakes near Stanislaus County |
| San Mateo County, CA | 75 km (47 mi) | WNW | earthquakes near San Mateo County |
| Merced County, CA | 75 km (47 mi) | E | earthquakes near Merced County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
60 earthquakes have been recorded within 50 km since this one.
- 2.7 5 km S of San Juan Bautista, CA
- 1.6 4 km WSW of Cupertino, CA
- 1.9 7 km ESE of Prunedale, CA
- 1.6 25 km NE of Hollister, CA
- 1.5 25 km NE of Hollister, CA
- 2.0 20 km E of Alum Rock, CA
- 2.4 6 km WSW of Gilroy, CA
- 1.7 9 km NE of Milpitas, CA
- 1.6 10 km WSW of Patterson, CA
- 1.6 11 km WSW of Patterson, CA
- 1.5 16 km SW of Westley, CA
- 1.6 12 km W of Patterson, CA
- 1.9 4 km WSW of Cupertino, CA
- 2.7 9 km NE of Alum Rock, CA
- 1.5 10 km WSW of Patterson, 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.
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.