How a 'Huge, Silent' Earthquake Caused a Mysterious Global Tsunami

newsweek ^ | 2/11/22 | ORLANDO JENKINSON ON

[BenLurkin]

In a study published in Geophysical Research Letters on February 8, scientists said that a total of five earthquakes, including one massive, "hidden" tremor, created the tsunami after striking close to the South Sandwich Islands on August 12, 2021, in the remote Southern Ocean off the coast of the continent of South America.

The study showed that tsunami-causing earthquakes such as the August 12 incident had complex patterns that could confound how scientists measure major tectonic activity

Researchers described an initial rupture that happened deep below the oceanic crust in between the South American and South Sandwich tectonic plates at a depth of around 29 miles. This earthquake, which measured 7.5 on the Richter Scale, then triggered other quakes, including a much shallower—and much more violent—third earthquake.

This later 8.2 magnitude earthquake generated most of the energy in the rupture series, the researchers said, and had far-reaching effects, with waves recorded thousands of miles from its source.

Yet for such a huge and globe-spanning event, the earthquake left barely any trace in typical data used by scientists to study such phenomena, puzzling researchers as to what had really happened.

[HighSierra5]

I don’t remember that quake at all. To really study all the details of a quake you need a lot of sensors nearby. Probably not very many in that area.

[Carriage Hill]

I don’t remember reading or hearing about the whole incident.Was it Karl Rove just revving-up his “Weather Machine”?

[ElkGroveDan]

Obviously caused by free market capitalism.

[Tennessee Nana]

Sandwich Islands as in Hawaii ???

[BenLurkin]

I think these are sort of between the Falklands and Antartica.

[BenLurkin]

[Ken Regis]

SPA station SHOULD have recorded the event.

Antarctica. South Pole. VERY LOW attenuation.

[BenLurkin]

[Larry Lucido]

If an earthquake falls in the forest and nobody hears it...wait..

[who_would_fardels_bear]

One day they will find out that the real reason that the condo in Surfside collapsed was because Rose O’Donnell fell out of bed.

[DocRock]

"To really study all the details of a quake you need a lot of sensors nearby. Probably not very many in that area."

I make time lapse videos of many large seismic events with spectros - here is a link to the time lapse of these large South Sandwich events. The South Sandwich station is at the bottom of the center column and the main event starts at 4:11 into the video. There are hot links to other events in the description.

MASH HERE

[PIF]

Beginning of a crustal displacement?

[dfwgator]

[Disambiguator]

Some Desitin will help with that.

[outofsalt]

Looking at your Spectros, Puerto Rico was orange during the SI and Haiti quakes.
Looking at Volcano Discovery archive showed only small stuff.
https://www.volcanodiscovery.com/earthquakes/puertorico/archive/2021-08-20-2021-08-22.html

[DocRock]

Different filters result in some base colors other than blue, and some stations are on a regular timed calibration or in error mode. The South Sandwich events that day are easier to target on nearby station’s propagation as the p and s waves spread. I didn’t mention that in the same video is a large 6.9 Alaska and a 7.2 Haiti quake. Thanks for your comments

[Battle Axe]

What is the antipodal of this event??

[Tennessee Nana]

Oh

[DocRock]

"What is the antipodal of this event??"

I usually put in a 'hollow globe' to show antipodal events. This video shows Alaska hits around the 2 minute mark. Starts around THIS TIME - MASH HERE

I've noted that exact antipodes almost never get a direct hit, and I think that is because of the different density of the core that the waves pass through, around or are deflected by. But I do think those are the nodes on a fundamental standing wave and the harmonics get hits, too. In this case around the equator. Just my observations.