The flat, grooved surface of this lava block was sandblasted by high-velocity pyroclastic surges during an eruption in 1775. The pyroclastic surges accompanied formation of the 700-m-wide Tolire Jaha maar on the NW flank of Gamalama.

Photo by Jack Lockwood, 1980 (U.S. Geological Survey).

This image is made available as a Public Domain Work, but proper attribution is appreciated.

Gamalama