Moderate mag. 3.7 earthquake - Sonoma County, 4.6 mi west of Cobb, California, USA, on Friday, 4 Dec 2020 2:45 am (GMT -8) -
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Moderate magnitude 3.7 earthquake at 3 km depth
4 Dec 10:48 UTC: First to report: USGS after 4 minutes.
4 Dec 15:24: Magnitude recalculated from 3.5 to 3.7.
4 Dec 18:28: Hypocenter depth recalculated from 2.4 to 2.6 km (from 1.5 to 1.6 mi).
4 Dec 15:24: Magnitude recalculated from 3.5 to 3.7.
4 Dec 18:28: Hypocenter depth recalculated from 2.4 to 2.6 km (from 1.5 to 1.6 mi).
Update Fri, 4 Dec 2020, 10:51
Small magnitude 3.5 earthquake 5 miles west of Cobb, California, United States3.5 quake 4 Dec 2:45 am (GMT -8)
Just 6 minutes ago, a 3.5-magnitude earthquake struck near Cobb, Lake County, California, USA. The tremor was recorded early morning on Friday 4 December 2020 at 2.45 am local time, at a very shallow depth of 1.5 miles below the surface.
The event was filed by the United States Geological Survey (USGS), the first seismological agency to report it.
A second report was later issued by the European-Mediterranean Seismological Centre (EMSC), which listed it as a magnitude 3.5 earthquake as well.
Based on the preliminary seismic data, the quake should not have caused any significant damage, but was probably felt by many people as light vibration in the area of the epicenter.
Weak shaking might have been felt in Cobb (pop. 1,800) located 5 miles from the epicenter.
Other towns or cities near the epicenter where the quake might have been felt as very weak shaking include Kelseyville (pop. 3,400) located 11 miles from the epicenter, Cloverdale (pop. 8,800) 11 miles away, Middletown (pop. 1,300) 11 miles away, Hidden Valley Lake (pop. 5,600) 13 miles away, Clearlake (pop. 15,200) 14 miles away, Healdsburg (pop. 11,700) 15 miles away, and Windsor (pop. 27,500) 19 miles away.
The event was filed by the United States Geological Survey (USGS), the first seismological agency to report it.
A second report was later issued by the European-Mediterranean Seismological Centre (EMSC), which listed it as a magnitude 3.5 earthquake as well.
Based on the preliminary seismic data, the quake should not have caused any significant damage, but was probably felt by many people as light vibration in the area of the epicenter.
Weak shaking might have been felt in Cobb (pop. 1,800) located 5 miles from the epicenter.
Other towns or cities near the epicenter where the quake might have been felt as very weak shaking include Kelseyville (pop. 3,400) located 11 miles from the epicenter, Cloverdale (pop. 8,800) 11 miles away, Middletown (pop. 1,300) 11 miles away, Hidden Valley Lake (pop. 5,600) 13 miles away, Clearlake (pop. 15,200) 14 miles away, Healdsburg (pop. 11,700) 15 miles away, and Windsor (pop. 27,500) 19 miles away.
Earthquake data:
Date & time: 4 Dec 2020 10:45:06 UTC -
Local time at epicenter: Friday, 4 Dec 2020 2:45 am (GMT -8)
Magnitude: 3.7
Depth: 2.6 km
Epicenter latitude / longitude: 38.82°N / 122.80883°W
(Sonoma County, California, United States)Nearest volcano: Clear Lake (17 km / 11 mi)
Nearby towns and cities:
7 km (5 mi) W of Cobb (pop: 1,780) --> See nearby quakes!
18 km (11 mi) E of Cloverdale (Sonoma County) (pop: 8,810) --> See nearby quakes!
22 km (14 mi) SW of Clearlake (Lake County) (pop: 15,200) --> See nearby quakes!
24 km (15 mi) NNE of Healdsburg (Sonoma County) (pop: 11,700) --> See nearby quakes!
24 km (15 mi) NNE of Russian River (pop: 11,700) --> See nearby quakes!
30 km (19 mi) N of Windsor (Sonoma County) (pop: 27,500) --> See nearby quakes!
43 km (27 mi) N of Santa Rosa (pop: 175,000) --> See nearby quakes!
54 km (34 mi) N of Rohnert Park (pop: 42,400) --> See nearby quakes!
74 km (46 mi) NW of Napa (pop: 80,400) --> See nearby quakes!
116 km (72 mi) NW of Concord (pop: 128,700) --> See nearby quakes!
Weather at epicenter at time of quake:
Clear Sky
4.8°C (41 F), humidity: 93%, wind: 1 m/s (3 kts) from NE
Primary data source: USGS (United States Geological Survey)Clear Sky
4.8°C (41 F), humidity: 93%, wind: 1 m/s (3 kts) from NEEstimated released energy: 2.2 x 1010 joules (6.22 megawatt hours, equivalent to 5.35 tons of TNT) More info
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.
| Magnitude | Depth | Location | Source |
| 3.7 | 2.6 km | 7km NW of The Geysers, CA, USA | USGS |
| 3.5 | 2 km | NORTHERN CALIFORNIA, USA | EMSC |
User reports for this quake (3)
User reports estimate the perceived ground shaking intensity according to the MMI (Modified Mercalli Intensity) scale.
10.8 km ENE of epicenter [Map] / Moderate shaking (MMI V) / vibration and rolling / 5-10 s
Murrieta california / Weak shaking (MMI III) / very short
Murrieta california / Weak shaking (MMI III) / very short
Earlier earthquakes in the same area
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