Mount Hannah

Mount Hannah is a mountain in the Mayacamas Mountains of the Northern California Coast Ranges. It is in Lake County, California.

Location
Mount Hannah is in Lake County, California. It is one of the mountains in the Cobb Mountain Area, many of which have volcanic origin. Others are Cobb Mountain, the most dominant, Seigler Mountain and Boggs Mountain. There are isolated small valleys and basins between the mountain peaks.

Mount Hannah has an elevation of 3692 ft. Clean prominence is 1338 ft. Isolation is 7.94 km. The nearest higher neighbor is Cobb Mountain to the south.

Geology
Mount Hannah formed quite quickly during a polarity transition. It was built up by a number of closely-spaced eruptions. Three of the dacites in the Mount Hannah sequence have been dated to between 0.90 and 0.92 million years ago. There are indications that there may be a crustal magma chamber about 10 - 15 km in diameter and a depth of 15 km below Mount Hannah, with a temperature above 550 C.