Simplified geologic map (left) and diagrammatic cross section (right) of Long Valley Caldera.

By California Volcano Observatory 2018 (approx.)

A two part figure with a shaded-relief map view of the Long Valley Caldera marked with the outlines of its resurgent dome, Mammoth Mountain, Crowley Lake, the caldera outline, and major roads. Below is a west-to-east cross-section cartoon of the caldera, showing the locations of these features as well as the depth of caldera fill, basement rocks, and the paths of cold and hot water near magmatic intrusions.

Detailed Description

Simplified geologic map (left) and diagrammatic cross section (right) of Long Valley Caldera. The resurgent dome, Doe Ridge, Mammoth Mountain, and the Inyo Craters and Domes all reflect volcanic activity since 760,000 years ago, when a giant eruption formed the caldera. The thermal springs in Hot Creek are fed by Sierra Nevada snowmelt that seeps underground and migrates eastward in the vicinity of partially molten rock (magma) beneath the western part of the caldera. The water cools as it migrates eastward beneath the ground (red arrows). From U.S. Geological Survey Fact Sheet, 2018-3009.

Sources/Usage

Public Domain.