Fumarolic activities with sulfur deposits are found at the twin summit craters and on the southeast flanks.

About 8,000 to 13,000 people attempt the climb each year, about 90% via routes from Camp Muir on the southeast flank.

Three eruptions have been reported from vents on the southeast flank during the late-19th and early-20th centuries.

Sulphur mining took place on the southeast flank until 1944.

Several satellite cones occur on the southeast flank and on the northern foot.

Kizimen has been erupting since November 2010, when a fissure opened on the volcano's southeast flank.

The first part of the hike follows the grass- and flower-covered slope on the southeast flank of the Eastern summit.

Route 220 lies along the southeast flank of the hill.

In 1562-64, an eruption on the southeast flank produced lava flows which reached the sea.

Fumaroles, mud pots and hot springs are located on the south and the southeast flanks.