Maar Formation

During March 1977, a volcano-like eruption was sighted near Becharof Lake 70 miles south of King Salmon. Geologists visiting the area found two holes, the largest about 1,000 feet across, on the near-level plain beside the lake. From these holes clouds of steam and ash billowed forth, and lava and rock fragments could be seen spurting upward occasionally.

At first it was not obvious whether the new activity was the beginning of a volcano or a transient breaching of the surface that would eventually lead to the formation of water-filled pits called maars. Maars are found elsewhere in the world, including the north side of the Seward Peninsula, near Cape Espenberg.