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Volcano, Storm, and News Updates for the Big Island of Hawaii.

Fissures sliced through Kīlauea Volcano’s lower East Rift Zone in 2018, and lava engulfed hundreds of structures. Lava chemistry tracked changes in composition as the draining and caldera collapses stirred up deeper, hotter parts of the summit magma system and sent mixed magma down the rift. USGS scientists shared their findings in a new article, “The tangled tale of Kīlauea’s 2018 eruption as told by geochemical monitoring” (abstract at http://ow.ly/SrPK50xtPxZ). From May 3-9, 2018, lavas erupting in the lower East Rift Zone were viscous and cool (~2030°F). These lavas were from pockets of magma left over from prior LERZ eruptions that had been cooling and crystallizing for more than 55 years. On May 13, an increase in inferred lava temperatures (~2066°F) heralded the arrival of hotter, more fluid lava. By May 28, activity focused at a single vent – fissure 8 – with a massive outpouring of hotter (~2093°F) lava that continued for more than 2 months. By the final 20 days of the eruption, most of the old magma stored within the active rift system had flushed out and the last and volumetrically more substantial source of magma was coming from the summit magma system. During the eruption, this information was used to inform response teams of shifts in eruptive conditions and potential hazards. The application of routine lava chemistry analysis provided an unparalleled opportunity to understand changes in magma characteristics during this rapidly evolving eruptive crisis. About the image: (A) Simplified model of Kīlauea’s magma system feeding the 2018 lower East Rift Zone eruption and locations of hypothesized magma end-members (b.s.l. is “below sea level”). (B) Fluid basalt erupting from fissure 20 on May 20, 2018. (C) Fissure 17 erupting andesite more explosively about a half a mile away.

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