Exploring the Geothermal Mysteries Under Nemrut’s Snow-Capped Surface

Astronaut photo of the snow-covered caldera of the Nemrut volcano in eastern Türkiye captured on April 17, 2022, by an astronaut aboard the International Space Station.

Lakes and lava flows fill the depression atop this geologically young stratovolcano in eastern Türkiye.

An astronaut aboard the International Space Station captured this photo of the snow-covered caldera of the Nemrut volcano in eastern Türkiye, along the western shore of Lake Van. Mount Nemrut (Nemrut Daği) is a geologically young stratovolcano and last erupted in 1650 C.E.

The eastern half of the caldera is partially filled by solidified lava flows from past eruptions. Snow cover present at the time of this photo accentuates pressure ridges that formed as the lava was flowing and cooling. These pressure ridges vary in size, thickness, and orientation due to the varying viscosity and flow direction of the lavas during eruptions.

Lake Nemrut (Nemrut Gölü) occupies the western half of the caldera, creating a rough crescent shape that partially submerges the old lava flows. This freshwater lake, reaching up to 176 meters deep, is accompanied by a smaller lake at the upper center of the caldera. This lake is fed by hot springs, which indicates ongoing geothermal activity beneath the caldera.

Astronaut photograph ISS069-E-16350 was acquired on April 17, 2022, with a Nikon D5 digital camera using a focal length of 1150 millimeters. The image was provided by the ISS Crew Earth Observations Facility and the Earth Science and Remote Sensing Unit at Johnson Space Center. The image was taken by a member of the Expedition 67 crew. It has been cropped and enhanced to improve contrast, and lens artifacts have been removed. The International Space Station Program supports the laboratory as part of the ISS National Lab to help astronauts take pictures of Earth that will be of the greatest value to scientists and the public and to make those images freely available on the Internet. Additional images taken by astronauts and cosmonauts can be viewed at the NASA/JSC Gateway to Astronaut Photography of Earth. Caption by Amber Turner/Jacobs-JETS II Contract at NASA-JSC.