Re: Rapid 3D analysis of rockfalls in Yosemite

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eeek

Rapid 3D analysis of rockfalls in Yosemite
June 28, 2018 04:14PM

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Registered: 15 years ago
Posts: 17,051

Yosemite National Park contains some of the world's most iconic landforms, including Half Dome, Yosemite Falls, and El Capitan. Although the cliffs of Yosemite Valley may appear static, rockfalls from these cliffs are common, with a rockfall occurring every four to five days on average. Rockfalls are key to shaping this iconic landscape but also pose risk to the four- to five-million visitors to the park annually.

https://www.sciencedaily.com/releases/2018/06/180628171423.htm

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Not quite The Geezer, but getting there

Re: Rapid 3D analysis of rockfalls in Yosemite
June 29, 2018 01:41AM

Registered: 9 years ago
Posts: 388

Interesting work, particularly the finding there was a "positive surface change" after the rockfall, in contrast to the "negative surface change indicative of material loss" usually seen after such events, indicating that the rock underneath had rotated out as a result of the rockfall and will therefore itself fall at some (not predictable) future time.

However, what caught my eye was this statement near the beginning of the article: "Rockfalls are the dominant erosional process in Yosemite, key to shaping this iconic landscape..." Is this an admission by the authors (including two NPS employees and one USGS employee) that Yosemite Valley's shape isn't due to glaciers but to rockfall?

Edited 2 time(s). Last edit at 06/29/2018 01:47AM by Not quite The Geezer, but getting there.

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balzaccom

Re: Rapid 3D analysis of rockfalls in Yosemite
June 29, 2018 06:40AM

Registered: 13 years ago
Posts: 1,425

I'm guessing that they'd say that the initial formation was glaciers, and now the rock falls are contributing their impact.

It's hard to argue that glaciers are the primary geological cause of any current changes in Yosemite Valley today---there hasn't been a glacier there in many thousands of years.

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Or just read a good mystery novel set in the Sierra; https://www.amazon.com/Danger-Falling-Rocks-Paul-Wagner/dp/0984884963