Ófærufoss
This two-tiered waterfall tumbles over a pair of strong, basaltic lava layers in central Iceland. These falls occur where the Nydri-Ófæru river plunges over the edge of Eldgjá, a half-kilometer wide and 40 kilometer long crack in the ground. That canyon is a fissure, the remnant of a huge outpouring of volcanic lava over a thousand years ago.
The fissure system Laki, that erupted in 1783 is linked to a larger magma plumbing system, most likely of the volcano Grímsvötn. Similarly this fissure is likely linked to the volcanic plumbing system beneath Katla, a large and active volcanic complex near Iceland’s southern coast.
The lower tier of this waterfall formerly featured a natural bridge of igneous rock. However, that bridge collapsed during a flood in 1993.
-JBB
Image credits: https://flic.kr/p/HgxZ6e http://bit.ly/2425jNq
References: http://www.katlageopark.com/geosites/eldgja-ofaerufoss/ http://www.worldwaterfalldatabase.com/waterfall/Ófaerufoss-14650/ http://bit.ly/1TrfQNl