Mag 8.2 Earthquake and aftershocks ~ 104 km SE of Perryville, Alaska

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On July 29, 2021, an 8.2 magnitude earthquake struck near Alaska at a depth of 32.2 km, prompting a tsunami warning that was later canceled as wave heights were minimal, measuring just over half a foot. The warning affected a significant stretch of coastline from Prince William Sound to Samalga Island. The earthquake was followed by numerous aftershocks, including a notable 6.9 magnitude quake occurring on August 14, 2021, just 50 km from the original epicenter. This series of seismic events has drawn comparisons to the devastating 1964 M9.2 earthquake in Alaska, highlighting the region's seismic activity. Overall, the impact of the recent quakes was relatively minor, with minimal injuries reported. The discussion emphasizes the frequency of major earthquakes, noting that the average occurrence is one M8.0 or greater event per year, with two such events recorded in 2021 alone.
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https://earthquake.usgs.gov/earthquakes/eventpage/ak0219neiszm/executive
https://earthquake.usgs.gov/earthquakes/eventpage/ak0219neiszm/region-info
  • 2021-07-29 06:15:47 (UTC)
  • 55.325°N 157.841°W
  • 32.2 km depth
A lot of aftershocks
https://earthquake.usgs.gov/earthqu...52.2816,-165.60791&extent=59.81168,-142.93213

https://www.usnews.com/news/us/articles/2021-07-29/tsunami-watch-issued-for-hawaii-after-82m-quake-hits-alaska
A tsunami warning for Alaska was canceled early Thursday when communities started reporting minor wave sizes, some just over a half foot (15.2 centimeters). A tsunami warning that also had been issued for https://www.usnews.com/news/best-states/hawaii was canceled, and officials said there was no threat to Guam, American Samoa or the Commonwealth of Northern Mariana Islands.

The tsunami warning for Alaska covered nearly a 1,000-mile (1,600-kilometer) stretch from Prince William Sound to Samalga Island, Alaska, near the end of the Aleutian Islands.
 
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One of my good friends was an MP at the largest Air Force Base in Alaska during the M9.2 earthquake in 1964. I've seen his presentation on the experience and the amazing damage; his description for how long it lasted is especially chilling and scary.

Here's a link to info on that previous event: https://earthquake.usgs.gov/earthquakes/events/alaska1964/

I'm glad that this one was lighter (relatively speaking) and that any injuries were minimal.
 
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Likes davenn and Tom.G
Thanks @Astronuc :smile:

I haven't even had time to post info on this quake
It had my seismo maxing out, even tho it is at the other end of the Pacific

1628501589455.gif


showing the trace up to about 5 minutes before it was to overwrite the signal

The worldwide avg is 1 x M8.0 + event per year. Some years have none, other years have two.
From memory, there was one year that had 4 x M8 + events

This year there has been two so far, the previous one back in early March 2021

cheers
Dave
 
Possibly related M 6.9 - 136 km SE of Perryville, Alaska
  • 2021-08-14 11:57:44 (UTC)
  • 55.085°N 157.540°W
  • 33.3 km depth
https://earthquake.usgs.gov/earthquakes/eventpage/ak021adyci6n/executive

Comparing the location of the 8.2 M earthquake: 55.325°N, 157.841°W, 32.2 km depth
with the location of the 6.9 earthquake: 55.085°N, 157.540°W, 33.3 km depth

The lateral separation assuming an ellipsoidal Earth 20.431 statute mi, 17.754 naut. mi, 32.880 km
Using https://stevemorse.org/nearest/distance.php
 
Astronuc said:
Possibly related M 6.9 - 136 km SE of Perryville, Alaska

definitely related, as in, an aftershock... it's just a bit up dip from the 8.2 ( ~ 50km)

Clipboard01.jpg
Dave
 
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