May 23, 2023 — Mauna Loa GPS Campaign
Another GPS survey benchmark being occupied on Mauna Loa. The metal disk on the ground beneath the tripod is the benchmark, which is cemented to the lava flow surface. Each year, the high-precision GPS unit is centered on the benchmark, and the height of the GPS unit on the tripod is accounted for when calculating how much that spot has moved vertically and horizontally over the past year. Mauna Kea is visible in the background. USGS photo by A. Ellis.