Light mag. 3.1 earthquake - Napa County, 10.2 mi east of Santa Rosa, Sonoma County, California, USA, on Thursday, 4 Mar 2021 7:53 am (GMT -8) -

Light mag. 3.1 earthquake - Napa County, 10.2 mi east of Santa Rosa, Sonoma County, California, USA, on Thursday, 4 Mar 2021 7:53 am (GMT -8)

Light magnitude 3.1 earthquake at 11 km depth

4 Mar 15:56 UTC: First to report: USGS after 3 minutes.
4 Mar 17:44: Magnitude recalculated from 3.2 to 3.1. Hypocenter depth recalculated from 10.0 to 10.4 km (from 6.2 to 6.5 mi).
4 Mar 18:36: Hypocenter depth recalculated from 10.4 to 10.6 km (from 6.5 to 6.6 mi).
Update Thu, 4 Mar 2021, 16:00
Small earthquake of magnitude 3.2 just reported 10 miles northeast of Santa Rosa, California, United States
3.2 quake 4 Mar 7:53 am (GMT -8)
3.2 quake 4 Mar 7:53 am (GMT -8)
A shallow magnitude 3.2 earthquake was reported in the morning near Santa Rosa, Sonoma County, California, USA.
According to the United States Geological Survey, the quake hit on Thursday 4 March 2021 at 7:53 am local time at a shallow depth of 6.2 miles. Shallow earthquakes are felt more strongly than deeper ones as they are closer to the surface. The exact magnitude, epicenter, and depth of the quake might be revised within the next few hours or minutes as seismologists review data and refine their calculations, or as other agencies issue their report.
A second report was later issued by the European-Mediterranean Seismological Centre (EMSC), which listed it as a magnitude 3.2 earthquake as well.
Towns or cities near the epicenter where the quake might have been felt as very weak shaking include Saint Helena (pop. 5,800) located 4 miles from the epicenter, Santa Rosa (pop. 175,000) 10 miles away, Rohnert Park (pop. 42,400) 13 miles away, Windsor (pop. 27,500) 16 miles away, Petaluma (pop. 60,400) 18 miles away, and Napa (pop. 80,400) 19 miles away. In Vallejo (pop. 121,300, 30 miles away), Fairfield (pop. 113,000, 31 miles away), and San Francisco (pop. 864,800, 49 miles away), the quake was probably not felt.
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Earthquake data:

Date & time: 4 Mar 2021 15:53:28 UTC -
Local time at epicenter: Thursday, 4 Mar 2021 7:53 am (GMT -8)
Magnitude: 3.1
Depth: 10.6 km
Epicenter latitude / longitude: 38.48017°N / 122.533°W (Napa County, California, United States)
Nearest volcano: Clear Lake (58 km / 36 mi)
Nearby towns and cities:
6 km (4 mi) WSW of Saint Helena (Napa County) (pop: 5,810) --> See nearby quakes!
16 km (10 mi) ENE of Santa Rosa (pop: 175,000) --> See nearby quakes!
21 km (13 mi) NE of Rohnert Park (pop: 42,400) --> See nearby quakes!
26 km (16 mi) ESE of Windsor (Sonoma County) (pop: 27,500) --> See nearby quakes!
29 km (18 mi) NNE of Petaluma (pop: 60,400) --> See nearby quakes!
30 km (18 mi) NW of Napa (pop: 80,400) --> See nearby quakes!
48 km (30 mi) NNW of Vallejo (pop: 121,300) --> See nearby quakes!
49 km (31 mi) WNW of Vacaville (pop: 96,800) --> See nearby quakes!
79 km (49 mi) N of San Francisco (pop: 864,800) --> See nearby quakes!
91 km (57 mi) W of Sacramento (pop: 490,700) --> See nearby quakes!
Weather at epicenter at time of quake:
Few Clouds 8.1°C (47 F), humidity: 85%, wind: 0 m/s (0 kts) from SE
Primary data source: USGS (United States Geological Survey)
Estimated released energy: 2.8 x 109 joules (783 kilowatt hours, equivalent to 0.674 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.
3.110.6 km6km WSW of St. Helena, CA, USAUSGS

User reports for this quake (16)

User reports estimate the perceived ground shaking intensity according to the MMI (Modified Mercalli Intensity) scale.
Leave a comment if you find a particular report interesting or want to add to it.
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Miramonte Pl, Santa Rosa, CA (7.4 km SW of epicenter) [Map] / Weak shaking (MMI III) / rattling, vibrating / very short : I was in bed, happened to have a garbage truck passing outside at that moment, and even though had never felt a vibration from such a truck, assumed that was the cause. My bed shook enough to be noticeable, so I though maybe a small earthquake. Then I saw an article on-line about it and then met another person on this street who also felt it.  
6.7 km ENE of epicenter [Map] / Light shaking (MMI IV) / rattling, vibrating / 2-5 s
Rincon Valley (11.4 km W of epicenter) [Map] / Very weak shaking (MMI II) / 2-5 s : dishes rattled in cupboard.  
12.4 km NNW of epicenter [Map] / Light shaking (MMI IV) / rattling, vibrating / 1-2 s
20.8 km SSE of epicenter [Map] / Weak shaking (MMI III) / rattling, vibrating / 1-2 s
9.6 km W of epicenter [Map] / Very weak shaking (MMI II) / single lateral shake / 1-2 s
6.7 km SW of epicenter [Map] / Weak shaking (MMI III) / 2-5 s
165 Oak.Shadow Dr. Santa Rosa 95409 (6.8 km SW of epicenter) [Map] / Weak shaking (MMI III) / single vertical bump / 1-2 s : I felt a single vertical bump at 7:54 PST. Caused the house to rattle about one second.  
  • I was sitting on the bed, it moved sideways back-and-forth for a count of three, the wall of the house was moving also. 7:54 a.m.
95409 (12.1 km W of epicenter) [Map] / Very weak shaking (MMI II) / single lateral shake / 1-2 s : Felt it  
Kenwood, ca / Light shaking (MMI IV) / 5-10 s
Santa Rosa / Light shaking (MMI IV) : I felt sharing  
Santa Rosa / Light shaking (MMI IV)
Saint Helena / Very weak shaking (MMI II) / 2-5 s
St Helena / Light shaking (MMI IV)
Napa, CA / Light shaking (MMI IV) / 1-2 s : It was very short, just long enough to wonder whether or not it had been an earthquake  
Santa Rosa / Weak shaking (MMI III) / very short
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