isolation, saddle and prominence questions

[argothor]

If Isolation is the measure of distance from the summit of the peak in question to the next higher neighbor, what would be the isolation of Mt. Everest?

If Saddle is the low point of the highest connecting ridge (highest ridge at its lowest point) to an elevation greater than the peak's maximum elevation, what would be the elevation of Everest's saddle?

And if Prominence is a measure of summit height minus saddle height, what would the prominence of Everest be?

I'm not really looking for actual numbers, but an understanding of how those would be figured for the highest point on the planet, or how they would be figured if you took North America, the United States, the contiguous U.S., or Colorado as separate entities in which you pretend the rest of the world outside of those geographic or political boundaries do not exist.

Curious minds at work.

[Layne Bracy]

If you haven't seen this, here's a good discussion:
http://peaklist.org/theory/orometry/art ... try_1.html

This variant of the definition helps with Everest:
"Put another way, prominence is the elevation difference between the summit and the lowest contour that encircles it and no higher summit."

This way, you simply have to decide what is the lowest contour on the planet. Generally, this is considered to be the sea level contour, giving Everest a prominence of 29035'. Or, using the 'dry-earth' model, where water is ignored, Everest' prominence would be (29035' + deepest ocean depth), and Mauna Kea is the 2nd-most prominent peak at around 30K. Personally, I like the dry-earth model, since it allows mountains that are completely or largely underwater their true prominence, rather than simply ignoring underwater topology.

Note that the authors or the article say that Everest does not have an isolation value. That works for me, though if someone wanted to say that the isolation of Everest equals the earth's circumference, I'd be OK with that.

[Layne Bracy]

Here's a list of dry-earth most prominent peaks from Adam Helman's book(copied from a discussion years ago on the yahoo prominence group - note that the Kammu Seamount summit can be reached with an 11m scuba-dive!

Table 6.1. World Prominences (to 5,000 meters) Neglecting Oceans
and Ice Caps - the Dry Earth Model

Mountain Location
Prominence(a,b) Elevation(b)

Everest Himalaya (see c) 8,848 (29,035)
Mauna Kea Hawaii 9,330 (30,610) 4,205
(13,796)
Vinson Massif Antarctica 8,272 (27,140) 4,892
(16,050)
Piton des Neiges Reunion Island 7,129 (23,389) 3,069
(10,069)
Aconcagua Andes 7,000 (22,966) 6,960
(22,834)
Mawson Peak Heard Island 6,395 (20,981) 2,745
(9,006)
Mount Cook New Zealand 6,354 (20,846) 3,754
(12,316)
Orohena Tahiti 6,341 (20,804) 2,241
(7,352)
Mount McKinley Alaska 6,168 (20,236) 6,194
(20,320)
Pico do Cano Fogo Island 6,129 (20,108) 2,829
(9,281)
Puncak Jaya New Guinea 6,084 (19,728) 4,884
(16,023)
Paget South Georgia 5,984 (19,403) 2,934
(9,626)
Kilimanjaro Tanzania 5,895 (19,340) 5,895
(19,340)
Teide Tenerife 5,648 (18,530) 3,718
(12,198)
Pico Azores 5,601 (18,376) 2,351
(7,713)
Cristobal Colon Colombia 5,500 (18,045) 5,775
(18,947)
Maromokotro Madagascar 5,426 (17,802) 2,876
(9,436)
Hiva Oa Marquesas 5,330 (17,487) 1,200
(3,937)
Mount Logan Yukon Territory 5,250 (17,224) 5,959
(19,550)
Kammu Seamountd (35 N, 172 E)
5,089 (16,696) -11 (36)
Bermuda Bermuda 5,004 (16,417) 79
(259)

a. Prominence values are accurate to perhaps 100 meters owing to
uncertainties in ocean sounding depths for the corresponding saddles.


b. Values are in meters and feet with the latter in parentheses.

c. As the world's highest mountain, no saddle exists leading to one
higher still.
Hence the prominence is undefined.

If one had to provide a value, within the Dry Earth Model some argue
that the
elevation difference with the global lowpoint, Challenger Deep of the
Marianas Trench,
is an appropriate value for Mount Everest's prominence - 19,772
meters (64,869 feet).

d. Enjoys the distinction of greatest prominence mountain that is
completely submerged.

[argothor]

The reason for my original inquiry was precipitated by reading Steph Abegg's interesting Is it a Peak, Mount or Mountain? article at

http://www.summitpost.org/article/60642 ... tain-.html

She used data from listsofjohn, but used the isolation of Rainier as 732 miles, but I wondered if using zero, since she is just referencing summits in Washington, would be more appropriate and whether or not it would change any of her results. Her response was that it wouldn't be zero but an "undetermined large value of isolation if only WA data were considered". Whereas in the site Layne provided it would be a "not applicable" value. Not being a math wiz, I'm not sure what the difference is between the two, but think of not applicable as zero.

Upon further reflection I also wonder if instead of a prominence of 13,222' for Rainier she should have used Rainier's full elevation of 14,410' since Rainier's saddle of 1,188' is in British Columbia.