September 17, 2024 —Kīlauea middle East Rift Zone eruption plume

A view under the plume of volcanic gas being transported by wind southwest from the eruption in Nāpau Crater on the middle East Rift Zone of Kīlauea. With permission from Hawaiʻi Volcanoes National Park, USGS Hawaiian Volcano Observatory gas specialists are traversing under the plume using a vehicle-mounted ultraviolet spectrometer on the closed portion of Chain of Craters Road, to quantify the amount of sulfur dioxide (SO₂) being emitted during the eruption. SO₂ emission rates are a key parameter to measure, as they can be used as a proxy for lava effusion rate and they dictate how much vog, or volcanic air pollution, there is downwind. USGS image by T. Nadeau.