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Strong mag. 5.0 earthquake - USA on 29 Jul 1:55 am (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 4 hours earlier.
Strong mag. 5.0 earthquake - USA on 29 Jul 1:55 am (GMT -8) Strong mag. 5.0 earthquake - USA on 29 Jul 1:55 am (GMT -8)

Strong magnitude 5.0 earthquake at 10 km depth

29 Jul 10:13 UTC: First to report: GFZ after 18 minutes.

Earthquake details

Date & timeJul 29, 2021 09:55:20 UTC -
Local time at epicenter29 Jul 1:55 am (GMT -8)
Depth10.0 km
Epicenter latitude / longitude55.31°N / 155.66°W (Gulf of Alaska, United States)
Antipode55.31°S / 24.34°E
Shaking intensityModerate shaking near epicenter
Felt1 report
Primary data sourceGFZ (German Research Centre for Geosciences)
Nearest volcanoYantarni (212 km / 132 mi)
Nearby towns and cities204 km (127 mi) SSW of Akhiok (pop: 72) | Show on map | Quakes nearby
211 km (131 mi) ESE of Chignik Lagoon (pop: 78) | Show on map | Quakes nearby
221 km (137 mi) ESE of Chignik Lake (pop: 73) | Show on map | Quakes nearby
229 km (142 mi) ESE of Perryville (pop: 113) | Show on map | Quakes nearby
256 km (159 mi) SW of Old Harbor (pop: 221) | Show on map | Quakes nearby
259 km (161 mi) SE of Port Heiden (pop: 98) | Show on map | Quakes nearby
306 km (190 mi) E of Sand Point (pop: 1,060) | Show on map | Quakes nearby
321 km (200 mi) SW of Womens Bay (pop: 719) | Show on map | Quakes nearby
331 km (206 mi) SW of Kodiak Station (pop: 1,300) | Show on map | Quakes nearby
340 km (211 mi) SW of Kodiak (pop: 6,250) | Show on map | Quakes nearby
Weather at epicenter at time of quakeOvercast Clouds 12.6°C (55 F), humidity: 80%, wind: 6 m/s (11 kts) from SSW
Estimated seismic energy released2 x 1012 joules (554 megawatt hours, equivalent to 477 tons of TNT) | 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.
5.010 kmSouth of AlaskaGFZ


Seismic station: College Outpost, Alaska, USA (COLA/IU network) | Distance from quake: 1146 km / 712 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 (2)

User reports estimate the perceived ground shaking intensity according to the MMI (Modified Mercalli Intensity) scale.
Kenai, Alaska (636.1 km NNE of epicenter) [Map] / not felt (reported through our app)
Sterling AK (646.6 km NNE of epicenter) [Map] / Very weak shaking (MMI II) / horizontal (sideways) swinging / 5-10 s (reported through our app)

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