July 20, 2025 — FTIR during Kīlauea summit eruption episode 29

During episode 29 of lava fountaining at the ongoing Kīlauea summit eruption, USGS scientists approached the caldera rim—with permission from Hawai‘i Volcanoes National Park—to measure volcanic gas emissions. The lava fountain seen here, on the morning of July 20, reached approximately 100 feet (30 meters) high. Using an FTIR (Fourier Transform Infrared Spectroscopy) instrument, the team analyzed gases released during the eruption. Measuring volcanic gas composition and concentration helps scientists better understand magma storage and supports ongoing volcanic hazard assessments. USGS photo by M. Benage.