There are isolated small valleys and basins between the mountain peaks.

The nearest higher neighbor is Cobb Mountain to the south.

[2] Mount Hannah formed quite quickly during a polarity transition.

[5] Three of the dacites in the Mount Hannah sequence have been dated to between 0.90 and 0.92 million years ago.

[4] There are indications that there may be a crustal magma chamber about 10–15 kilometres (6.2–9.3 mi) in diameter and a depth of 15 kilometres (9.3 mi) below Mount Hannah, with a temperature above 550 °C (1,022 °F).