QuakeIndex

Earthquake · reviewed by a seismologist

M 1.7ml

Earthquake near Julian, CA

No earthquake was likely felt in Julian in the 24 hours to 8:06 am PST (16:06 UTC). The last one was M 4.9, 151 km (94 mi) ESE, at 10:27 am PST on 3 November 2026, estimated intensity II (weak) in town; 321 felt reports to USGS. Every earthquake near Julian

This page: a magnitude 1.7 earthquake was recorded 24 km (15 mi) east-southeast of Julian, CA, at 11:40 pm PST on 9 December 2020 (07:40 UTC), 9.7 km deep.

USGS: 24km ESE of Julian, CA

76 km (47 mi) ENE of San Diego, CA

11:40 pm PST, Dec 9, 2020 · · 9.7 km deep · released about 9.3 lb of TNT

Every earthquake near Julian Felt it? Tell USGS Check my area
10 km30 km60 km120 km N San Diego County 39 kmRiverside County 87 kmImperial County 94 km
Distance rings around the epicentre, with the nearest towns at their true direction and later quakes as coloured dots. Not a shaking map — see the USGS ShakeMap for that.
When
11:40 pm PST on 9 December 2020 ()
Where
24 km (15 mi) east-southeast of Julian, CA · earthquakes near Julian
Magnitude
M 1.7 (ml)
Depth
9.7 km below the surface
Felt
no reports yet
Nearest
San Diego County, 39 km W
Nearest mapped fault
Elsinore fault, 5 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 2163 days ago

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 7 km (4 mi) from the epicentre. In Julian, 24 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.

Earthquakes near other towns within 30 km: Pine Valley, Borrego Springs, Descanso.

How big was it?

This earthquake released about 9.3 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.

  1. Mineral, Virginia 2011 M 5.8 1,600,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 1,100,000× the energy of this one
  3. Around the size people start to feel M 3.0 100× the energy of this one
  4. This earthquake M 1.7 about 9.3 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 5.2 on 2016-06-10 — about 200,000 times the energy of this one.

Before 2016, the USGS record lists 13 earthquakes of M5 or more within 50 km; the five largest:

  1. 6.6 The 1968 Borrego Mountain, California Earthquake · 30 km NE of this epicentre
  2. 6.6 The 1987 Superstition Hills, California Earthquake · 47 km E of this epicentre
  3. 6.4 The 1954 San Jacinto Fault, California Earthquake · 41 km NE of this epicentre
  4. 6.0 16km WSW of Oasis, CA · 44 km NNE of this epicentre
  5. 5.7 Eastern San Diego County, California · 32 km NE 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 33.0110, -116.3588. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
San Diego County, CA 39 km (24 mi) W earthquakes near San Diego County
Riverside County, CA 87 km (54 mi) NNE earthquakes near Riverside County
Imperial County, CA 94 km (58 mi) E earthquakes near Imperial County

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

Aftershocks so far

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

  1. 1.6 5km SW of Salton City, CA
  2. 1.7 20km ESE of Julian, CA
  3. 2.9 5km SW of Salton City, CA
  4. 1.7 20km ESE of Julian, CA
  5. 2.2 5km SW of Salton City, CA
  6. 1.5 12km NW of Ocotillo Wells, CA
  7. 1.9 10km ENE of Borrego Springs, CA
  8. 1.6 14km SE of Ocotillo Wells, CA
  9. 1.9 16km N of Ocotillo, CA
  10. 2.1 17km ESE of Julian, CA
  11. 1.6 11km NNW of Ocotillo, CA
  12. 1.6 9km E of San Diego Country Estates, CA
  13. 1.6 17km ESE of Julian, CA
  14. 1.7 10km ENE of Borrego Springs, CA
  15. 1.5 17km N of Borrego Springs, 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

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