LINEAR AND ARCUATE CAVERNOUS LANDFORMS OF MARS AND EARTH AS HABITATION SITES AND REFUGIA: SOME OPPORTUNITIES AND CONSTRAINTS

We concur that outburst channels downslope from a controversial crevice cave on Ascraeus Mons were eroded by lava, not water and we present photodocumentation of presumably similar lava flowing actively on Kilauea Volcano, Hawaii, USA. We conclude that exploration, study and habitation of spacious, accessible caves on Mars remain viable, even though NASA space suit developers suggest that subsurface astronaut activities are not feasible because the risk to human life outweighs the potential benefits of such investigations. We exclude volcanic crevice caves and most lava tube caves from further consideration but urge special attention to crevice caves in stratified rock, hollow volcanic tumuli, dissolution caves in beds of salt, piping (suffosion) caves in poorly consolidated clastics, glacier caves, littoral caves in ancient shorelines and cavernous spaces beneath dsplaced monoliths.