Earthquake · reviewed by a seismologist
M 1.7md
Earthquake near Shandon, CA
No earthquake was likely felt in Shandon in the 24 hours to 8:46 am PST (16:46 UTC). The last one was M 2.0, 13 km (8 mi) NE, at 3:39 pm PST on 2 December 2025, estimated intensity II (weak) in town. Every earthquake near Shandon
This page: a magnitude 1.7 earthquake was recorded 27 km (17 mi) east-southeast of Shandon, CA, at 11:17 am PDT on 20 May 2020 (18:17 UTC), 14 km deep.
USGS: 23km NNW of Simmler, CA
- When
- 11:17 am PDT on 20 May 2020 ()
- Where
- 27 km (17 mi) east-southeast of Shandon, CA · earthquakes near Shandon
- Magnitude
- M 1.7 (md)
- Depth
- 14 km below the surface
- Felt
- no reports yet
- Nearest
- San Luis Obispo County, 34 km WSW
- 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 2359 days ago
Earthquake alerts for Shandon, 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 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 Shandon, 27 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.
How big was it?
This earthquake released about 10 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.
- Mineral, Virginia 2011 M 5.8 1,500,000× the energy of this one
- Magna, Utah 2020 M 5.7 1,000,000× the energy of this one
- Around the size people start to feel M 3.0 92× the energy of this one
- This earthquake M 1.7 about 10 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 4.3 on 2019-12-17 — about 7,900 times the energy of this one.
Before 2016, the USGS record lists 5 earthquakes of M5 or more within 50 km:
- 6.5 1922 Parkfield, California Earthquake · 27 km NNW of this epicentre
- 6.0 2004 Parkfield, California Earthquake · 39 km NW of this epicentre
- 5.5 1966 Parkfield, California Earthquake · 33 km NNW of this epicentre
- 5.0 11 km NNE of Shandon, California · 31 km NW of this epicentre
- 5.0 11 km NNE of Shandon, California · 31 km NW 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 35.5330, -120.1195. Map © OpenStreetMap contributors.
Nearby places
| Place | Distance | Direction from the epicentre | |
|---|---|---|---|
| San Luis Obispo County, CA | 34 km (21 mi) | WSW | earthquakes near San Luis Obispo County |
| Kings County, CA | 66 km (41 mi) | NNE | earthquakes near Kings County |
| Santa Barbara County, CA | 111 km (69 mi) | S | earthquakes near Santa Barbara County |
| Monterey County, CA | 133 km (83 mi) | NW | earthquakes near Monterey County |
Places and coordinates from the US Census Bureau Gazetteer (2024). Distances are from the epicentre.
Aftershocks so far
45 earthquakes have been recorded within 50 km since this one.
- 1.7 6km E of Atascadero, CA
- 1.6 9km NNW of Cholame, CA
- 1.7 16km SSE of Shandon, CA
- 1.8 6km E of Atascadero, CA
- 1.6 22km S of Kettleman City, CA
- 2.4 24km SE of Santa Margarita, CA
- 1.6 21km SE of Shandon, CA
- 3.0 5km S of Shandon, CA
- 2.0 23km NNE of Nipomo, CA
- 1.7 17km SSE of Kettleman City, CA
- 2.4 15km SSE of Kettleman City, CA
- 1.7 16km SSE of Kettleman City, CA
- 3.0 17km SE of Kettleman City, CA
- 1.7 10km SSE of Parkfield, CA
- 1.9 10km SSE of Parkfield, 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.