Mag. 3.9 earthquake - 24 mi north of Santa Rosa, Sonoma County, California, on Wednesday, 12 August 2020 at 11:45 (GMT) -

Mag. 3.9 earthquake  - 24 mi north of Santa Rosa, Sonoma County, California, on Wednesday, 12 August 2020 at 11:45 (GMT)

Minor magnitude 3.9 earthquake at 4 km depth

12 Aug 11:46 UTC: First to report: USGS after 1 minutes.
Aug 12 11:49: Magnitude recalculated from 4.1 to 4.0.
Hypocenter depth recalculated from 8.0 to 4.1 km.
Aug 12 11:51: Magnitude recalculated from 4.0 to 3.9.
Date & time: 12 Aug 2020 11:45:43 UTC -
Magnitude: 3.9
Depth: 4.1 km
Epicenter latitude / longitude: 38.78667°N / 122.74917°W (California, United States)
Nearest volcano: Clear Lake (21 km / 13 mi)
Nearby towns and cities:
5 km (3 mi) SSW of Cobb (pop: 1,780)
17 km (10 mi) W of Hidden Valley Lake (pop: 5,580)
22 km (14 mi) SSW of Clearlake (Lake County) (pop: 15,200)
22 km (14 mi) NNE of Healdsburg (Sonoma County) (pop: 11,700)
23 km (14 mi) E of Cloverdale (Sonoma County) (pop: 8,810)
39 km (24 mi) N of Santa Rosa (pop: 175,000)
111 km (69 mi) WNW of Sacramento (pop: 490,700)
116 km (72 mi) NNW of San Francisco (pop: 864,800)
Primary data source: USGS
Estimated released energy: 4.5 x 1010 joules (12.4 megawatt hours, equivalent to 10.7 tons of TNT) More info
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Data for the same earthquake reported by different agencies

Info: The more agencies report about the same quake and post similar data, the more confidence you can have in the data. It takes normally up to a few hours until earthquake parameters are calculated with near-optimum precision.
MagnitudeDepthLocationSource
M 3.94.1 km1km NNE of The Geysers, CA (USA)USGS
M 3.94 kmNorthern California (USA)EMSC

User reports for this quake (10)

User reports estimate the perceived ground shaking intensity according to the MMI (Modified Mercalli Intensity) scale.
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5655 Saint Helena Road, Santa Rosa CA / Weak shaking (MMI III) : I did not feel a "shaking" at all, but only one powerful jerk/thrust.
cobb / Light shaking (MMI IV) : woke me up
Santa Rosa, CA / Very weak shaking (MMI II)
Noe Valley (United States, 119 km S of epicenter) : Just a light jiggle in SF (reported through EMSC)
Lower Lake (United States, 18 km NE of epicenter) : I FELT A LITTLE SHAKE IN OUR TRAILER...I THOUGHT IT WAS A TREMOR AT THE TIME... (reported through EMSC)
San Francisco (United States of America, 114 km S of epicenter) : Mild shake, 5 seconds long. (reported through EMSC)
Ross (United States, 91 km S of epicenter) : Was sound asleep but a small shake plus rattling sound woke me up. (reported through EMSC)
Suisun (United States, 87 km SE of epicenter) : Was in the tub, not sure if I was feeling a shake, but looked up to see toner sloshing in bottle a little. No reaction from Chihuahuas and cat. (reported through EMSC)
Napa (United States, 67 km SE of epicenter) : Minor back and forth for less than 5 seconds. In bed, St. Helena. (reported through EMSC)
Santa Rosa (United States of America, 36 km S of epicenter) : I was awake but lying down. Sharp jolt felt from North, wall mounted shelves on brackets made cracking sound as jolt felt. Slight swaying motion to room briefly upon standing. (reported through EMSC)
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Earlier earthquakes in the same area

Mag. 3.9 earthquake - 24 mi north of Santa Rosa, Sonoma County, California, on Wednesday, 12 August 2020 at 11:45 (GMT)
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