Mount Hannah is a mountain in the

Mayacamas Mountains The Mayacamas Mountains are located in northwestern California in the United States. The mountain range is part of the Northern Inner Coast Ranges, of the California Coast Ranges System. Geography The Mayacamas Mountains are located south of the ...

of the Northern

California Coast Ranges The Coast Ranges of California span from Del Norte or Humboldt County, California, south to Santa Barbara County. The other three coastal California mountain ranges are the Transverse Ranges, Peninsular Ranges and the Klamath Mountains. P ...

. It is in

Lake County, California Lake County is a county located in the north central portion of the U.S. state of California. As of the 2020 census, the population was 68,163. The county seat is Lakeport. The county takes its name from Clear Lake, the dominant geographic fe ...

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 Cobb Mountain is the tallest mountain in the Mayacamas Mountains of California. Location Cobb Mountain's main summit is located in Lake County, west of the town of Cobb. Like nearby Mount Saint Helena, Cobb Mountain is tall enough to receiv ...

, the most dominant,

Seigler Mountain Seigler Mountain is a mountain in the Mayacamas Mountains of the Northern California Coast Ranges. It is in Lake County, California. Name The mountain is named after Thomas Seigler, who discovered the Seigler Springs to the east of the mountain, ...

and

Boggs Mountain Boggs Mountain is a mountain the Mayacamas Mountains in Lake County, California. Part of the mountain holds the Boggs Mountain Demonstration State Forest. About 80% of the trees were burned in the September 2015 Valley Fire. Name In the early day ...

. There are isolated small valleys and basins between the mountain peaks. Mount Hannah has an elevation of . Clean prominence is . Isolation is . The nearest higher neighbor is

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 A magma chamber is a large pool of liquid rock beneath the surface of the Earth. The molten rock, or magma, in such a chamber is less dense than the surrounding country rock, which produces buoyant forces on the magma that tend to drive it upw ...

about in diameter and a depth of below Mount Hannah, with a temperature above .

Notes

Sources

* * * {{DEFAULTSORT:Hannah, Mount Mountains of Lake County, California Mayacamas Mountains