Earthquake · reviewed by a seismologist
M 1.9md
Earthquake near Newark, CA
No earthquake was likely felt in Newark in the 24 hours to 11:35 pm PST (07:35 UTC). The last one was M 3.5, 53 km (33 mi) ESE, at 7:21 am PDT on 27 September 2026, estimated intensity II (weak) in town; 8 felt reports to USGS. Every earthquake near Newark
This page: a magnitude 1.9 earthquake was recorded 4 km (3 mi) southwest of Newark, CA, at 11:46 pm PDT on 22 September 2021 (06:46 UTC), 12 km deep. 2 people have reported feeling it to USGS.
USGS: 4km SW of Newark, CA
12 km (7 mi) N of Mountain View, CA · 33 km (20 mi) NW of San Jose, CA
- When
- 11:46 pm PDT on 22 September 2021 ()
- Where
- 4 km (3 mi) southwest of Newark, CA · earthquakes near Newark
- Magnitude
- M 1.9 (md)
- Depth
- 12 km below the surface
- Felt
- 2 reports · strongest reported intensity II
- Nearest
- Alameda County, 21 km NE
- Nearest mapped fault
- Hayward fault, 11 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 1874 days ago
Earthquake alerts for Newark, CA
Get a notification in this browser when USGS records an earthquake near Newark, 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, people at rest would likely notice it out to about 9 km (6 mi) from the epicentre. In Newark, 4 km away, the estimate is intensity II (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: Newark 4 km, intensity II · East Palo Alto 7 km, intensity II · Fremont 9 km, intensity II · Palo Alto 9 km, intensity II. Estimated for each town centre; each link is that town's own record.
How big was it?
This earthquake released about 23 lb of TNT. Magnitude is logarithmic: each whole step up releases about 32 times more energy, so a magnitude 2.9 would have released about 32 times as much.
- Mineral, Virginia 2011 M 5.8 660,000× the energy of this one
- Magna, Utah 2020 M 5.7 470,000× the energy of this one
- Around the size people start to feel M 3.0 42× the energy of this one
- This earthquake M 1.9 about 23 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 4.5 on 2019-10-15 — about 6,500 times the energy of this one.
Before 2016, the USGS record lists 17 earthquakes of M5 or more within 50 km; the five largest:
- 7.9 The 1906 San Francisco, California Earthquake · 50 km WNW of this epicentre
- 6.2 Near San Jose, California · 34 km SE of this epicentre
- 6.2 The 1984 Morgan Hill, California Earthquake · 41 km ESE of this epicentre
- 6.1 Near San Jose, California · 42 km SE of this epicentre
- 5.8 7 km NNW of Boulder Creek, California · 36 km S 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 37.5065, -122.0777. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| Alameda County, CA | 21 km (13 mi) | NE | earthquakes near Alameda County |
| San Mateo County, CA | 28 km (17 mi) | WSW | earthquakes near San Mateo County |
| Santa Clara County, CA | 47 km (29 mi) | SE | earthquakes near Santa Clara County |
| Contra Costa County, CA | 47 km (29 mi) | NNE | earthquakes near Contra Costa County |
| Santa Cruz County, CA | 55 km (34 mi) | S | earthquakes near Santa Cruz County |
| Marin County, CA | 84 km (52 mi) | NW | earthquakes near Marin County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
56 earthquakes have been recorded within 50 km since this one.
- 1.8 1km NE of San Ramon, CA
- 2.7 2km NE of San Ramon, CA
- 1.6 2km NE of San Ramon, CA
- 2.0 1km NE of San Ramon, CA
- 1.5 1km NE of San Ramon, CA
- 1.6 1km NE of San Ramon, CA
- 1.6 1km NE of San Ramon, CA
- 1.8 1km NE of San Ramon, CA
- 2.0 1km NE of San Ramon, CA
- 2.0 1km NE of San Ramon, CA
- 1.5 2km NE of San Ramon, CA
- 3.0 1km NE of San Ramon, CA
- 1.7 1km NE of San Ramon, CA
- 2.3 1km NE of San Ramon, CA
- 2.1 1km NNE of San Ramon, 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.