Erta Ale

Tectonics and subduction of the lava lake's crust in 2008

Tectonics and subduction of the lava lake's crust  in 2008
Most spattering activity takes place at a hornito on the southwestern shoreline (top right).
Tectonics and subduction of the lava lake's crust  in 2008
Degassing is mainly taking place from the hornito's vent and causes mild lava spattering.
Tectonics and subduction of the lava lake's crust  in 2008
Sometimes waves from the lake up to one metre high erode and enlarge the lips of the hornito's vent.
Tectonics and subduction of the lava lake's crust  in 2008
Big waves from bubble eruptions lead to the formation of lava stalactites at the hornito's lips (top left).
Tectonics and subduction of the lava lake's crust  in 2008
Lava upwelling takes place mostly along the southeastern shoreline, far away from the hornito.
Tectonics and subduction of the lava lake's crust  in 2008
Upwelling sometimes causes brief and violent bursts which lift the shiny lava crust on the lake's surface.
Tectonics and subduction of the lava lake's crust  in 2008
After the bursts fresh yellow lava splashes over the colder, and therefore darker, lava crust.
Tectonics and subduction of the lava lake's crust  in 2008
Such bursts agitate the lake's surface causing waves and cracking up the crust on the eastern shoreline.
Tectonics and subduction of the lava lake's crust  in 2008
At the NW shore lava is subducted into the depths of the lake, while some incandescent lava gets squeezed out through fissures.
Tectonics and subduction of the lava lake's crust  in 2008
Tension induced into the crust by the subduction process often extends the skin so much that red lava appears from below.
Tectonics and subduction of the lava lake's crust  in 2008
Sometimes a crustal plate is thrusted above another one, and incandescent lava is exposed along the wavefront.
Tectonics and subduction of the lava lake's crust  in 2008
Occasionally the crust becomes so thick that it does not get subducted and accumulates on the western shoreline forming shiny folds.
Photos by Marco Fulle, taken from a distance of 70 meters with 135mm and 500mm lenses and digital single lens reflex camera (equivalent focal lenghts of 200mm and 750mm on 24x36 film).