Mono Lake Volcanic Field

Paoha and Negit Islands, Mono Lake, California

The islands of Mono Lake were built by recent eruptions of lava and cinder and by uplift of the shallow lake bottom caused by the rise of magma beneath the lake. The two islands are less than about 2,000 years old, and the lava flows on the north flank of Paoha Island are only about 250 years old.

Pahoa Island in Mono Lake, California.

This aerial view toward the south shows the northeastern side of Paoha Island; the Mono Craters and Sierra Nevada are in the far distance.

Most of Paoha Island consists of layers of lake sediments that were pushed up above the water level as magma rose into the crust below. The north (bottom of photo) and east (left side of island) tips of the island consist of craters and lava flows that may have erupted as recently as A.D. 1720-1850. (Credit: Bailey, R. A.. Public domain.)


Negit Island in Mono Lake, California.

Negit Island in Mono Lake, California viewed toward the northwest. The lava flows of Negit Island erupted between about 2,000 and 200 years ago. Three separate vents erupted dacite lava flows that run parallel to each other. (Credit: Bailey, R. A.. Public domain.)