I posted some photos of lava tubes in the Dong Nai area of south Vietnam. A report will be published in due course.
http://cavinglizsea.blogspot.com/2014/02/vietnam-lava-tubes-dong-nai-2014-pt-2.html
http://cavinglizsea.blogspot.com/2014/02/vietnam-lava-tubes-dong-nai-2014-pt-2.html