Volcano Watch: Something new from something old: A new geologic map of Hawaii

USGS map A portion of the updated 2021 Geologic Map of the State of Hawaii showing part of the District of Puna, where recent lava flow units have been added to the map. In this figure, the new lava flow units have been colored differently than the published map to emphasize their location.

The original purpose of geologic mapping in Hawaii was to understand the distribution of groundwater and soils to support agriculture. But as geologic maps have been developed over time, they’ve provided basic information on how the Hawaiian Islands evolved, the workings of individual volcanoes, and the relative degree of long-term hazards posed.