Greg, It looks more like a giant sinkhole to me. God help those people.
FLAT perfectly sloped soil after a torrent carved that hole,...nope, the triangular shaped sloped material is a CONCRETE structure, mate. looks to be where it ends, ...that or some of it's GONE.
TC
Greg, I think I 'misspoke'. I should have said that your photo reminded me of a giant sinkhole. Didn't mean it in the literal sense.
"For joy of knowing what may not be known we take the golden road to Samarkand." James Elroy Flecker