Seen from space, few other extinct volcanoes look as exotic and spectacular as Waw an Namus. The volcano, located deep in the Sahara Desert in the Fezzan region of southwestern Libya, appears as a smear of dark basalticash and tephra that contrasts sharply with the light-colored sand of the Sahara Desert.
The Operational Land Imager (OLI) on Landsat 8 captured this view of the feature on May 29, 2015. While the precise date of the most recent eruption is not known, the lack of erosion and weathering implies that it probably occurred in the last few thousand years. South of the ash field, mud streams have begun the slow process of eroding the tephra and ash away. The ash field extends around a much smaller caldera that is about 4 kilometers (2 miles) wide. Calderas are hollowed-out circular depressions that form at the summit of volcanoes when magma is withdrawn or erupted from a shallow underground magma reservoir.
The lower image shows a closer view of the caldera. Within it, three small salty lakes ringed with vegetation are visible. The volcano gets its name from the lakes, which are reportedly home to thriving communities of mosquitos. (In Arabic, Waw an Namus means “crater of mosquitos.”) The edge of a cinder cone is also visible near the center of the caldera. Cinder cones are steep, conical hills that accumulate around volcanic vents. They are made from small glassy rock fragments that pile up around vents as ash and congealed lava erupts.
The beauty and unique appearance of Waw an Namus has long fascinated travelers.