Strong mag. 5.8 earthquake - North Pacific Ocean, 98 km northeast of Hasaki, Chōshi-shi, Chiba, Japan, on Wednesday, Aug 4, 2021 5:33 am (GMT +9) -

Strong mag. 5.8 earthquake - North Pacific Ocean, 98 km northeast of Hasaki, Chōshi-shi, Chiba, Japan, on Wednesday, Aug 4, 2021 5:33 am (GMT +9)

Strong magnitude 5.8 earthquake at 33 km depth

3 Aug 20:39 UTC: First to report: VolcanoDiscovery after 6 minutes.
3 Aug 20:42: Now using data updates from GFZ
3 Aug 20:43: Magnitude recalculated from 5.6 to 5.8. Epicenter location corrected by 4.2 km (2.6 mi) towards WNW.
3 Aug 21:06: Hypocenter depth recalculated from 10.0 to 33.0 km (from 6.2 to 21 mi). Epicenter location corrected by 10.6 km (6.6 mi) towards WNW.
Update Tue, 3 Aug 2021, 20:48
Magnitude 5.8 earthquake strikes near Mito, Mito-shi, Ibaraki, Japan
5.8 quake 4 Aug 5:33 am (GMT +9)
5.8 quake 4 Aug 5:33 am (GMT +9)
A shallow magnitude 5.8 earthquake was reported early morning near Mito, Mito-shi, Ibaraki, Japan.
According to the German Research Centre for Geosciences (GFZ), the quake hit on Wednesday 4 August 2021 at 5:33 am local time at a shallow depth of 10 km. 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 France's Réseau National de Surveillance Sismique (RéNaSS), which listed it as a magnitude 6.0 earthquake. A third agency, the European-Mediterranean Seismological Centre (EMSC), reported the same quake at magnitude 5.8.
Based on the preliminary seismic data, the quake was probably felt by many people in the area of the epicenter. It should not have caused significant damage, other than objects falling from shelves, broken windows, etc.
In Hasaki (pop. 39,200) located 103 km from the epicenter, and Kashima-shi (pop. 65,800) 110 km away, the quake should have been felt as light shaking.
Weak shaking might have been felt in Hitachi (pop. 186,300) located 117 km from the epicenter, Katsuta (pop. 156,000) 120 km away, Hitachi-Naka (pop. 156,800) 120 km away, Katori-shi (pop. 83,200) 124 km away, Mito (pop. 246,500) 126 km away, and Iwaki (pop. 357,300) 130 km away.
VolcanoDiscovery will automatically update magnitude and depth if these change and follow up if other significant news about the quake become available. If you're in the area, please send us your experience through our reporting mechanism, either online or via our mobile app. This will help us provide more first-hand updates to anyone around the globe who wants to know more about this quake.
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Earthquake data

Date & time: Aug 3, 2021 20:33:39 UTC -
Local time at epicenter: Wednesday, Aug 4, 2021 5:33 am (GMT +9)
Magnitude: 5.8
Depth: 33.0 km
Epicenter latitude / longitude: 36.22°N / 141.74°E (North Pacific Ocean, Japan)
Antipode: 36.22°S / 38.26°W
Nearest volcano: Nasu (202 km / 126 mi)
Nearby towns and cities:
98 km (61 mi) NE of Hasaki (pop: 39,200) --> See nearby quakes!
102 km (64 mi) ENE of Kashima-shi (pop: 65,800) --> See nearby quakes!
106 km (66 mi) ESE of Hitachi (pop: 186,300) --> See nearby quakes!
110 km (68 mi) E of Katsuta (pop: 156,000) --> See nearby quakes!
110 km (68 mi) E of Hitachi-Naka (pop: 156,800) --> See nearby quakes!
117 km (72 mi) E of Mito (pop: 246,500) --> See nearby quakes!
117 km (73 mi) ENE of Katori-shi (pop: 83,200) --> See nearby quakes!
120 km (74 mi) SE of Iwaki (pop: 357,300) --> See nearby quakes!
194 km (120 mi) ENE of Tokyo (pop: 8,336,600) --> See nearby quakes!
208 km (129 mi) ENE of Yokohama (pop: 3,574,400) --> See nearby quakes!
337 km (209 mi) E of Honshū Island (pop: 104,000,000) --> See nearby quakes!
311 km (194 mi) NE of Shikine-jima Island (pop: 600) --> See nearby quakes!
Weather at epicenter at time of quake:
Clear Sky 26.5°C (80 F), humidity: 86%, wind: 5 m/s (9 kts) from SSW
Primary data source: GFZ (German Research Centre for Geosciences)
Estimated released energy: 3.2 x 1013 joules (8.78 gigawatt hours, equivalent to 7558 tons of TNT or 0.5 atomic bombs!) 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.
Mag.DepthLocationSource
5.833 kmNear East Coast of Honshu, JapanGFZ
5.920 kmNEAR EAST COAST OF HONSHU, JAPANEMSC
5.710 kmJapan: Near TokyoRENASS
5.810 km122 Km ENE of Hasaki, JapanUSGS
6.09.8 kmOff East Coast of Honshu, Japan [Sea: Japan]INGV
5.837 kmNear East Coast of Honshu, JapanGeoAu
5.810 kmNear East Coast of Honshu, JapanBMKG

User reports for this quake (9)

User reports estimate the perceived ground shaking intensity according to the MMI (Modified Mercalli Intensity) scale.
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Yokosuka, Kanagawa (216 km WSW of epicenter) [Map] / Light shaking (MMI IV) / horizontal (sideways) swinging / 10-15 s : I was in the shower and felt my apartment sway back and forth | One user found this interesting.  
Narita / Very weak shaking (MMI II) / complex motion difficult to describe / 30-60 s : I felt the bed moving under me. I got up and walked and could feel movement under my feet. | One user found this interesting.  
Gotemba / Weak shaking (MMI III) / horizontal (sideways) swinging / 10-15 s : Slight shaking for about 15 seconds | One user found this interesting.  
Shibuya (193.7 km WSW of epicenter) [Map] / Very weak shaking (MMI II) / horizontal (sideways) swinging / 5-10 s
Yokosuka, Kanagawa (213.8 km WSW of epicenter) [Map] / Weak shaking (MMI III) / horizontal (sideways) swinging / 30-60 s
Funabashi / Weak shaking (MMI III)
Sendai-shi (241.3 km NNW of epicenter) [Map] / Light shaking (MMI IV) / 15-20 s
Saitama / Weak shaking (MMI III)
Mobara / Very weak shaking (MMI II) / 1-2 minutes
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Aftershocks

More info

Recorded aftershocks, latest first (71 quakes)

  • 15 Sep 2021 06:12 UTC
    | M 2.6 |
    52.8 km (32.8 mi) depth
    |
    44 km (27 mi) distance
    | NIED | Details
  • 08 Sep 2021 15:09 UTC
    | M 2.6 |
    60.6 km (37.7 mi) depth
    |
    13 km (8 mi) distance
    | NIED | Details
  • 08 Sep 2021 08:15 UTC
    | M 2.9 |
    24 km (14.9 mi) depth
    |
    36 km (22 mi) distance
    | NIED | Details
  • 08 Sep 2021 05:42 UTC
    | M 2.8 |
    21.7 km (13.5 mi) depth
    |
    36 km (23 mi) distance
    | NIED | Details
  • 07 Sep 2021 21:34 UTC
    | M 2.7 |
    21.9 km (13.6 mi) depth
    |
    27 km (17 mi) distance
    | NIED | Details
  • 04 Sep 2021 02:34 UTC
    | M 2.8 |
    50.8 km (31.6 mi) depth
    |
    20 km (12 mi) distance
    | NIED | Details
  • 21 Aug 2021 15:26 UTC
    | M 2.7 |
    52.8 km (32.8 mi) depth
    |
    19 km (12 mi) distance
    | NIED | Details
  • 16 Aug 2021 06:11 UTC
    | M 3.0 |
    45.8 km (28.5 mi) depth
    |
    27 km (17 mi) distance
    | NIED | Details
  • 14 Aug 2021 00:53 UTC
    | M 2.8 |
    54.6 km (33.9 mi) depth
    |
    16 km (10 mi) distance
    | NIED | Details
  • 10 Aug 2021 06:38 UTC
    | M 3.2 |
    54.2 km (33.7 mi) depth
    |
    12 km (7 mi) distance
    | NIED | Details
  • 07 Aug 2021 11:27 UTC
    | M 3.3 |
    46.4 km (28.8 mi) depth
    |
    29 km (18 mi) distance
    | NIED | Details
  • 06 Aug 2021 14:55 UTC
    | M 3.1 |
    4.6 km (2.9 mi) depth
    |
    35 km (22 mi) distance
    | NIED | Details
  • 06 Aug 2021 04:28 UTC
    | M 3.5 |
    16 km (9.9 mi) depth
    |
    31 km (19 mi) distance
    | NIED | Details
  • 05 Aug 2021 21:10 UTC
    | M 3.7 |
    11.4 km (7.1 mi) depth
    |
    15 km (9 mi) distance
    | NIED | Details
  • 05 Aug 2021 20:32 UTC
    | M 3.0 |
    12.1 km (7.5 mi) depth
    |
    11 km (7 mi) distance
    | NIED | Details
  • 05 Aug 2021 14:45 UTC
    | M 2.6 |
    45.7 km (28.4 mi) depth
    |
    14 km (8 mi) distance
    | NIED | Details
  • Show all

Earlier earthquakes in the same area

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