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North America's largest and perhaps most popular volcano is the plume of mantle situated right beneath the surface of what we arbitrarily call Yellowstone National Park.

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This image shows the two most iconic symbols of Yellowstone--bison and geysers.

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This image shows the very core of Yellowstone--a mantle plume high in energy but low in sulfur, which means when it erupts--and I do mean WHEN--it might not release enough aerosols to disrupt the global climate, despite popular opinions. (After all, no two volcanoes have the same personalities.)

Because of its proximity to the Rocky Mountains and the Colorado Plateau, the plateau in which Yellowstone situates beneath stands an average of 8,000 feet above sea level.

Our Yellowstone is located at coordinates 44.4280 degrees North and 110.5885 West. This alternate Yellowstone is located at coordinates 40.4977 degrees North and 121.4207 West, the location of Lassen Peak in California, the southernmost active volcano in the Cascades.

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Its last eruption was in the late 1910s, over half a century before the more culturally prominent Mount Saint Helens, which is situated in the same mountain chain. Its proximity to the Pacific Plate makes Lassen taller than the Yellowstone plateau--10,457 feet above sea level.

In this alternate scenario, a combination of Pacific subduction and a stationary mantle plume turned what we'd have called Lassen Peak into an alternate, Californian Yellowstone. Would this combination have affected local elevation in any way?

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    $\begingroup$ Reminder to close-voters... (Maybe I should have gone for the moderator elections so I could send messages to everyone to read that...) $\endgroup$ – Frostfyre Aug 26 '16 at 12:38
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Counter-intuitively, despite Mount Lassen being taller than the rim of the Yellowstone Caldera, Californian Yellowstone would be at a lower altitude than Wyoming Yellowstone.

The elevation of the Yellowstone area is dominated by the remnants of the Laramide Orogeny, with a "natural" ground level of around 7000 feet. The Yellowstone hotspot isn't much of an uplift source: at ~8000 feet elevation, it's only about a thousand feet higher, and it's significantly lower than the 10,000+-foot peaks around it. It's more of a "mountain eraser": if you follow its path backwards, you'll see it's cut a broad swath through the Basin-and-Range Province.

The Cascade Range is a chain of relatively short uplift mountains, with a scattering of dramatically taller volcanoes. Mount Lassen sits in an area where the "natural" level of the ground is around 5000 feet. Taking this into account, a "Californian Yellowstone" would likely be a plateau about 6000 feet high, with a low rim of uplift-mountain remnants surrounding it on three sides, and a broad mountain-free track stretching southwest to the Pacific coast.

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If the subduction is different, I expect the mountains to be in different places and the land to be shaped differently in general. If the caldera is in a different place then of course the elevation will be lower where it wound up and higher where it didn’t happen.

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