Source: US Geological Survey
USGS Hawaiian Volcano Observatory staff are conducting the annual Mauna Loa GPS campaign. During the survey, GPS instruments are deployed at established benchmarks so that their recorded positions can be compared with those from previous years to discern small changes in ground deformation associated with volcanic activity. Temporary GPS receivers and antennas are placed on tripods centered over benchmarks, which serve as a reference point for centering of the antenna. The equipment is left in place to collect data for a couple of days at each site. USGS photo by A. Ellis.
Campaign, also known as ‘survey’, GPS data augment the permanent, continuously recording GPS instruments in HVO’s monitoring network. In this photo, a tripod mounted with a GPS antenna is temporarily installed over a benchmark the rim of Moku‘āweoweo, the caldera at the summit of Mauna Loa. Hawai‘i Volcanoes National Park Mauna Loa Summit Cabin is visible in the background. USGS image by A. Ellis.