Earthquake · reviewed by a seismologist
M 1.8md
Earthquake near San Martin, CA
No earthquake was likely felt in San Martin in the 24 hours to 4:35 am PST (12:35 UTC). The last one was M 2.5, 17 km (10 mi) SE, at 7:27 pm PST on 1 November 2026, estimated intensity II (weak) in town; 2 felt reports to USGS. Every earthquake near San Martin
This page: a magnitude 1.8 earthquake was recorded 18 km (11 mi) northeast of San Martin, CA, at 7:24 am PST on 28 January 2019 (15:24 UTC), 49 km deep.
USGS: 18km NE of San Martin, CA
34 km (21 mi) ESE of San Jose, CA · 23 km (14 mi) NNE of Gilroy, CA
- When
- 7:24 am PST on 28 January 2019 ()
- Where
- 18 km (11 mi) northeast of San Martin, CA · earthquakes near San Martin
- Magnitude
- M 1.8 (md)
- Depth
- 49 km below the surface
- Felt
- no reports yet
- Nearest
- Santa Clara County, 21 km WNW
- Nearest mapped fault
- Greenville fault, 9 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 2816 days ago
Earthquake alerts for San Martin, CA
Get a notification in this browser when USGS records an earthquake near San Martin, CA. No account or email needed.
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 minor earthquake. Quakes this small are rarely felt and do not cause damage.
At this magnitude and depth it was probably too small to be felt, even directly above it. In San Martin, 18 km away, the estimate is intensity I (not felt). 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.
Earthquakes near other towns within 30 km: Morgan Hill, Gilroy.
How big was it?
This earthquake released about 16 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.
- Mineral, Virginia 2011 M 5.8 970,000× the energy of this one
- Magna, Utah 2020 M 5.7 680,000× the energy of this one
- Around the size people start to feel M 3.0 61× the energy of this one
- This earthquake M 1.8 about 16 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 4.1 on 2017-10-10 — about 2,600 times the energy of this one.
Before 2016, the USGS record lists 27 earthquakes of M5 or more within 50 km; the five largest:
- 6.9 The 1989 Loma Prieta, California Earthquake · 41 km WSW of this epicentre
- 6.5 Near Morgan Hill, California · 18 km WSW of this epicentre
- 6.2 Near San Jose, California · 33 km WNW of this epicentre
- 6.2 The 1984 Morgan Hill, California Earthquake · 24 km NW of this epicentre
- 6.1 Near San Jose, California · 31 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 37.1832, -121.4530. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Santa Clara County, CA | 21 km (13 mi) | WNW | earthquakes near Santa Clara County |
| Santa Cruz County, CA | 53 km (33 mi) | WSW | earthquakes near Santa Cruz County |
| Stanislaus County, CA | 58 km (36 mi) | NE | earthquakes near Stanislaus County |
| Merced County, CA | 65 km (40 mi) | E | earthquakes near Merced County |
| Alameda County, CA | 66 km (41 mi) | NW | earthquakes near Alameda County |
| San Benito County, CA | 71 km (44 mi) | SSE | earthquakes near San Benito County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
55 earthquakes have been recorded within 50 km since this one.
- 3.1 11km ENE of San Martin, CA
- 1.9 11km ENE of San Martin, CA
- 1.7 10km NNE of Tres Pinos, CA
- 1.8 4km ESE of Tres Pinos, CA
- 1.6 14km SSE of Livermore, CA
- 2.1 10km WSW of Ridgemark, CA
- 2.1 9km NNE of Alum Rock, CA
- 1.9 10km ENE of Morgan Hill, CA
- 1.9 3km NNW of Hollister, CA
- 1.7 7km WSW of Gilroy, CA
- 1.5 9km NNE of Alum Rock, CA
- 1.6 8km SE of Seven Trees, CA
- 1.8 7km WSW of Gilroy, CA
- 1.7 7km WSW of Gilroy, CA
- 2.5 12km NNE of Morgan Hill, 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.