QuakeIndex

quarry blast · reviewed by a seismologist

M 1.7md

Earthquake near Thermalito, CA

No earthquake was likely felt in Thermalito in the 24 hours to 6:02 am PST (14:02 UTC). The last one was M 5.6, 142 km (88 mi) W, at 8:10 am PDT on 24 June 2026, estimated intensity III (weak) in town; 5,311 felt reports to USGS. Every earthquake near Thermalito

No: USGS classifies this as a quarry blast, not an earthquake. A magnitude 1.7 quarry blast was recorded 9 km (6 mi) north of Thermalito, CA, at 2:02 pm PST on 3 January 2019 (22:02 UTC), less than 1 km deep.

USGS: 10km N of Thermalito, CA

26 km (16 mi) SE of Chico, CA · 115 km (71 mi) N of Sacramento, CA

2:02 pm PST, Jan 3, 2019 · · -0.2 km deep · released about 12 lb of TNT

10 km30 km60 km120 km N Butte County 8 kmYuba County 42 kmSutter County 63 kmGlenn County 69 kmColusa County 72 kmNevada County 78 kmPlumas County 79 kmTehama County 80 kmSierra County 92 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
2:02 pm PST on 3 January 2019 ()
Where
9 km (6 mi) north of Thermalito, CA · earthquakes near Thermalito
Magnitude
M 1.7 (md)
Depth
-0.2 km below the surface
Felt
no reports yet
Nearest
Butte County, 8 km N
Nearest mapped fault
Foothills fault system, 14 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 2779 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 13 km (8 mi) from the epicentre. In Thermalito, 9 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: Oroville, South Oroville, Oroville East, Berry Creek, Paradise, Durham.

USGS catalogues this as quarry blast, not an earthquake.

How big was it?

This earthquake released about 12 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 1,200,000× the energy of this one
  2. Magna, Utah 2020 M 5.7 870,000× the energy of this one
  3. Around the size people start to feel M 3.0 78× the energy of this one
  4. This earthquake M 1.7 about 12 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

No earthquake of M4 or more has been recorded within 50 km since our catalogue begins in 2016.

Before 2016, the USGS record lists 3 earthquakes of M5 or more within 50 km:

  1. 5.7 The 1975 Oroville, California Earthquake · 19 km SSE of this epicentre
  2. 5.2 4 km E of Palermo, California · 20 km SSE of this epicentre
  3. 5.1 5 km ENE of Palermo, California · 19 km SSE 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 39.5962, -121.5952. Map © OpenStreetMap contributors.

Nearby places

PlaceDistanceDirection from the epicentre
Butte County, CA 8 km (5 mi) N earthquakes near Butte County
Yuba County, CA 42 km (26 mi) SSE earthquakes near Yuba County
Sutter County, CA 63 km (39 mi) S earthquakes near Sutter County
Glenn County, CA 69 km (43 mi) W earthquakes near Glenn County
Colusa County, CA 72 km (45 mi) SW earthquakes near Colusa County
Nevada County, CA 78 km (49 mi) ESE earthquakes near Nevada County

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

Aftershocks so far

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

  1. 1.8 1km NNE of Chico, CA
  2. 2.1 6km S of Bucks Lake, CA
  3. 2.1 8km W of La Porte, CA
  4. 1.8 5km SW of Hamilton City, CA
  5. 2.4 6km SW of Hamilton City, CA
  6. 1.9 10km NNW of Oroville, CA
  7. 1.8 14km N of Colusa, CA
  8. 2.5 15km ENE of Willows, CA
  9. 1.6 4km NNE of Hamilton City, CA
  10. 1.6 12km SE of Willows, CA
  11. 2.2 16km N of Colusa, CA
  12. 1.9 6km SW of Hamilton City, CA
  13. 1.8 6km SW of Hamilton City, CA
  14. 2.5 5km NNE of Hamilton City, CA
  15. 2.5 4km SE of Concow, 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.