Photo Information

Source of landslide high on south side of Casita Volcano, Nicaragua
Photograph by J.L. Macias on March 23, 1999

Close view of the source area for the landslide high on the south flank of Casita Volcano. The landslide scar exposes rocks and deposits that form Casita. The light-colored rocks in the uppermost part of the source area were relatively unaltered by weathering or hydrothermal activity, but many fractures cut through the rocks; low-grade alteration was concentrated along the fractures because groundwater had preferentially moved along the cracks. The dark purple rock is hydrothermally-altered basaltic scoria. As the landslide moved down the volcano, it increased in size as it eroded highly altered rocks of the volcano's lower flank.

 

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U.S. Department of the Interior, U.S. Geological Survey, Menlo Park, California, USA
URL http://volcanoes.usgs.gov/Imgs/Jpg/Casita/30710609_018_caption.html
Contact: VHP WWW Team
Last modification: 13 November 1999 (SRB)