Mount Waesche is a mountain of volcanic origin at the southern end of the Executive Committee Range in Marie Byrd Land, Antarctica. It is 3,292 metres (10,801 ft) high, and stands 20 kilometres (12 mi) southwest of Mount Sidley, the highest volcano in Antarctica. The mountain lies southwest of the Chang Peak caldera and is largely covered with snow and glaciers, but there are rock exposures on the southern and southwestern slopes. The volcano may have been active as late as the Holocene, with tephra layers recovered from ice cores possibly originating from Mount Waesche. Seismic activity has been recorded both from the volcano and from an area south of it and might reflect ongoing volcanic activity. Name and research history It was discovered by the United States Antarctic Service expedition on a flight on December 15, 1940, and named for Vice Admiral Russell R. Waesche, United States Coast Guard, member of the Antarctic Service Executive Committee. Field studies took place in 1999-2000 and 2018-2019. Geography and geomorphology Mount Waesche lies in Marie Byrd Land, one of the most inaccessible areas of Antarctica. It is one of 18 volcanoes in that region, which were active from the Oligocene to recent times. The origin of volcanic activity there has been correlated to the activity of a mantle plume underneath the crust. The region also includes the highest volcano in Antarctica, Mount Sidley, which reaches height. There may be as many as 138 volcanoes buried underneath the ice. The volcano is high. It is a double volcano, with the north-northeasterly Chang Peak caldera and the south-southwesterly Mount Waesche proper. The Chang Peak caldera is wide and the largest in Marie Byrd Land; Mount Waesche rises almost over and lies on the rim of the caldera. Mount Waesche is the more conspicuous peak and lava flows crop out on its southern and southwestern flank, while a wide caldera lies at its summit. On the northern side of Chang Peak caldera lies a high outcrop, and it and another outcrop consist of pumice and vitrophyre. Both volcanoes appear to be mainly formed by lava. At least five parasitic vents lie on the volcano, with several aligned on radial fissure vents; they are cinder cones and scoria cones and have erupted cinder, lava and volcanic bombs. A long large radial dyke projects from Mount Waesche and is the only part of the edifice where hyaloclastic