The HI-SEAS site has Mars-like geology which allows crews to perform high-fidelity geological field work and add to the realism of the mission simulation. The Martian regolith examined by the CheMin instrument (Blake et al. 2012) is very similar to the weathered basaltic materials found in this part of Hawaii. The site is a former cinder rock quarry on the side of a spatter cone. It is surrounded by relatively recent lava flows with very little plant or animal life present. None of the sparse flora or fauna is rare which mitigates the likelihood of adverse environmental impact due to mission activities. The flows include a wide variety of volcanic features to explore, such as lava tubes, skylights, channels, and tumuli. The HI-SEAS site is visually isolated, yet accessible by a dirt road, and a hospital and other emergency services are within a one hour driving distance (much less by helicopter). It has a cool, dry climate that varies very little over the year, enabling long-duration missions.