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Strong mag. 5.5 earthquake - 164 mi east of Sand Point, Aleutians East, Alaska, USA, on 28 Jul 10:32 pm (GMT -8) -

This quake was likely an aftershock of the 8.2 quake Chignik Earthquake, Gulf of Alaska, July 29, 2021 06:15 GMT, which had occurred 17 minutes earlier.
Strong mag. 5.5 earthquake - 164 mi east of Sand Point, Aleutians East, Alaska, USA, on 28 Jul 10:32 pm (GMT -8) Strong mag. 5.5 earthquake - 164 mi east of Sand Point, Aleutians East, Alaska, USA, on 28 Jul 10:32 pm (GMT -8)

Strong magnitude 5.5 earthquake at 10 km depth

29 Jul 06:38 UTC: First to report: USGS after 6 minutes.
29 Jul 06:41: Hypocenter depth recalculated from 15.7 to 16.2 km (from 9.8 to 10.1 mi). Epicenter location corrected by 5.8 km (3.6 mi) towards NW.
... [show all] ...
29 Jul 08:28: Magnitude recalculated from 5.6 to 5.5. Hypocenter depth recalculated from 5.0 to 10.0 km (from 3.1 to 6.2 mi). Epicenter location corrected by 60 km (37 mi) towards SSE.

Earthquake details

Date & timeJul 29, 2021 06:32:30 UTC -
Local time at epicenter28 Jul 10:32 pm (GMT -8)
StatusConfirmed
Magnitude5.5
Depth10.0 km
Epicenter latitude / longitude54.9213°N / 156.4119°W (Gulf of Alaska, Alaska, United States)
Antipode54.921°S / 23.588°E
Shaking intensityModerate shaking
Felt4 reports
Primary data sourceUSGS (United States Geological Survey)
Nearest volcanoBlack Peak (176 km / 109 mi)
Nearby towns and cities204 km (127 mi) SE of Chignik Lagoon (pop: 78) | Show on map | Quakes nearby
205 km (127 mi) ESE of Perryville (pop: 113) | Show on map | Quakes nearby
209 km (130 mi) SE of Chignik Lake (pop: 73) | Show on map | Quakes nearby
264 km (164 mi) E of Sand Point (pop: 1,060) | Show on map | Quakes nearby
264 km (164 mi) SSE of Port Heiden (pop: 98) | Show on map | Quakes nearby
265 km (165 mi) SSW of Akhiok (pop: 72) | Show on map | Quakes nearby
377 km (234 mi) E of King Cove (pop: 1,010) | Show on map | Quakes nearby
384 km (239 mi) SW of Womens Bay (pop: 719) | Show on map | Quakes nearby
394 km (245 mi) SW of Kodiak Station (pop: 1,300) | Show on map | Quakes nearby
403 km (251 mi) SW of Kodiak (pop: 6,250) | Show on map | Quakes nearby
Weather at epicenter at time of quakeOvercast Clouds 12.1°C (54 F), humidity: 87%, wind: 6 m/s (12 kts) from SSW
Estimated seismic energy released1.1 x 1013 joules (3.12 gigawatt hours, equivalent to 2682 tons of TNT or 0.2 atomic bombs!) | about seismic energy
Show interactive Map
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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
5.510 kmSouth of AlaskaUSGS
5.820 kmSOUTH OF ALASKAEMSC
5.810 kmNear AnchorageRENASS
5.818 kmAlaska PeninsulaGFZ
5.924 kmSouth of AlaskaGeoAu

Seismograms

Seismic station: College Outpost, Alaska, USA (COLA/IU network) | Distance from quake: 1203 km / 747 mi | Show on map | Station Info
Seismic station College Outpost, Alaska, USA: vertical movement plot around time of quake (source: IRIS/BUD)
Seismogram (vertical component) around time of quake. Thin dotted red line indicates time of quake. Seismic waves arrive some time later, depending on distance. Source: IRIS Buffer of Uniform Data (BUD) webtool
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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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North Pole AK (1203.4 km NNE of epicenter) [Map] / Weak shaking (MMI III) / complex rolling (tilting in multiple directions) : Light rolling  
Whitehorse (1411.5 km NE of epicenter) [Map] / not felt (reported through our app)
Soldotna Alaska (683.6 km NNE of epicenter) [Map] / not felt : Did not feel it. Nothing moved. Dogs where normal. No shaking (reported through our app)  
North Pole AK (1203.4 km NNE of epicenter) [Map] / Weak shaking (MMI III) / complex rolling (tilting in multiple directions) : Light rolling  
Whitehorse, Yukon (1411.9 km NE of epicenter) [Map] / not felt (reported through our app)
Metlakatla (1575.6 km ENE of epicenter) [Map] / not felt (reported through our app)
near Cohoe, Kenai Peninsula, Alaska (665.5 km NNE of epicenter) [Map] / Moderate shaking (MMI V) (reported through our app)
Homer / not felt
Anchorage / Weak shaking (MMI III) / rattling, vibrating / 15-20 s : Something fell in the kitchen and I felt some shaking.  

Earlier earthquakes in the same area

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