An HVO geologist uses a high-precision Global Positioning System (GPS) unit to c

An HVO geologist uses a high-precision Global Positioning System (GPS) unit to collect latitude, longitude, and altitude data on a down-dropped portion of Kīlauea's caldera. On December 18, the area was evaluated for potential monitoring camera locations to better document changes in the surface level of Kīlauea's summit crater lake, which is visible in the background of the image. HVO fieldwork in this closed area of Hawai‘i Volcanoes National Park is done with permission of the National Park Service to support public safety and further scientific understanding of Kīlauea Volcano. USGS photo by K. Mulliken.