Drudge Retort: The Other Side of the News
Thursday, July 29, 2021

USGS Alaska Earthquake Center: The July 29, 2021, (July 28, 2021 local time) M8.2 earthquake southeast of Perryville, Alaska (south of the Alaska Peninsula), occurred as the result of thrust faulting on or near the subduction zone interface between the Pacific and North America plates. The preliminary focal mechanism solution indicates rupture occurred on a fault dipping either shallowly to the northwest, or steeply to the southeast. The location, mechanism and depth - and the large size of the event - are all consistent with slip occurring on the subduction zone interface between the two plates. At the location of this event, the Pacific plate converges with North America to the northwest at a rate of about 64 mm/yr, subducting at the Alaska-Aleutians trench ~125 km to the southeast of the earthquake. While commonly plotted as points on maps, earthquakes of this size are more appropriately described as slip over a larger fault area. Reverse faulting events of the size of the July 29 earthquake are typically about 200x80 km in size (length x width) Large earthquakes are common in the Alaska-Aleutian subduction zone. Since 1900, 8 other earthquakes M7 and larger have occurred within 250 km of the July 29, 2021 event, including earthquakes of M7.8 on July 22, 2020 (located 62 km west of the July 29, 2021 event) and M7.6 on October 19, 2020 (located 145 west of the July 29, 2021 event). Given the temporal and spatial proximity of the July 29, 2021 earthquake to the two previous large earthquakes in July and October 2020, those previous events were foreshocks of the July 2021 earthquake. An earthquake of M8.2 also occurred on November 10, 1938 within 40 km of the July 29, 2021 event. While initial information is incomplete, the July 29 earthquake may have ruptured partially or completely into the ruptured region of the 1938 earthquake. The Alaska-Aleutian Trench also hosted the second largest earthquake recorded by modern seismic instrumentation, the M9.2 March 27 1964 earthquake, which ruptured to within about 250 km of this event, at the eastern end of the 1938 rupture area. The 1938 event produced a small tsunami that was recorded both locally and in Hilo, Hawaii. The remote location of the earthquake resulted in little impact to people and infrastructure.



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hokey f--- Bullwinkle!

#1 | Posted by RightisTrite at 2021-07-29 07:47 AM | Reply

I couldn't have asked for a better birthday present!

#2 | Posted by HanoverFist at 2021-07-29 08:37 AM | Reply

"I couldn't have asked for a better birthday present!"


Why is that? Did Sarah Palin get run over by a speeding glacier?

#3 | Posted by Twinpac at 2021-07-29 08:51 AM | Reply | Funny: 1

You gotta throw us a bone. Wachoo talkin' bout, H-Ova?

#4 | Posted by oldwhiskeysour at 2021-07-29 08:57 AM | Reply

Having a geology background, I can honestly say,
"that's a biggie"...

#5 | Posted by earthmuse at 2021-07-29 10:01 AM | Reply

Anyone that considers a potential disaster for thousands, if not millions is just sick piece of s**t.

#6 | Posted by danni at 2021-07-29 10:30 AM | Reply

"Did Sarah Palin get run over by a speeding glacier?"

That was seriously funny Twin!

#7 | Posted by danni at 2021-07-29 12:07 PM | Reply


Just hoping that Karma finally came to collect her due. That's all.

#8 | Posted by Twinpac at 2021-07-29 12:55 PM | Reply

It was a little fortuitous that it happened way out in the Aleutians and not in the Gulf of Alaska like in 1964.

#9 | Posted by randomcanyon at 2021-07-29 04:12 PM | Reply

Having a geology background, I can honestly say,
"that's a biggie"...

#5 | POSTED BY EARTHMUSE AT 2021-07-29 10:01 AM | REPLY

You haven't seen mine yet.

#10 | Posted by BellRinger at 2021-07-30 01:31 AM | Reply

Earthquakes trigger more earthquakes further down the fault. That particular fault is currently highly loaded and the entire Pacific Northwest is overdue for large earthquakes. Over the next 5-10 years, we're going to get a series of large quakes off the Northwest coast of NA. Including a possible 9.0 off the coast of Washington.

#11 | Posted by s1l3ntc0y0t3 at 2021-07-30 09:05 PM | Reply

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