Abstract
AbstractThe 2018 lower East Rift Zone (LERZ) eruption and the accompanying collapse of the summit caldera marked the most destructive episode of activity at Kı̄lauea Volcano in the last 200 years. The eruption was extremely well‐monitored, with extensive real‐time lava sampling as well as continuous geodetic data capturing the caldera collapse. This multiparameter data set provides an exceptional opportunity to determine the reservoir geometry and magma transport paths supplying Kı̄lauea’s LERZ. The forsterite contents of olivine crystals, together with the degree of major element disequilibrium with carrier melts, indicates that two distinct crystal populations were erupted from Fissure 8 (termed high‐ and low‐Fo). Melt inclusion entrapment pressures reveal that low‐Fo olivines (close to equilibrium with their carrier melts) crystallized within the Halema’uma’u reservoir (∼2‐km depth), while many high‐Fo olivines (>Fo81.5; far from equilibrium with their carrier melts) crystallized within the South Caldera reservoir (∼3–5‐km depth). Melt inclusions in high‐Fo olivines experienced extensive post‐entrapment crystallization following their incorporation into cooler, more evolved melts. This favored the growth of a CO2‐rich vapor bubble, containing up to 99% of the total melt inclusion CO2 budget (median = 93%). If this CO2‐rich bubble is not accounted for, entrapment depths are significantly underestimated. Conversely, reconstructions using equation of state methods rather than direct measurements of vapor bubbles overestimate entrapment depths. Overall, we show that direct measurements of melts and vapor bubbles by secondary‐ion mass spectrometry and Raman spectroscopy, combined with a suitable H2O‐CO2 solubility model, is a powerful tool to identify the magma storage reservoirs supplying volcanic eruptions.
Highlights
IntroductionThe 2018 lower East Rift Zone (LERZ) eruption was the largest and most destructive in the last 200 years of activity at Kılauea Volcano, Hawai’i (Neal et al, 2019), accompanied by the highest co-eruptive fluxes of SO2 ever measured at Kılauea (up to 200 kt a day; Kern et al, 2020; Whitty et al, 2020), and very high lava WIESER ET AL.Geochemistry, Geophysics, Geosystems effusion rates (100–300 m3/s; Neal et al, 2019; Patrick, Dietterich et al, 2019)
May 2018, but only six melt inclusions from July 2018 and one from Aug 2018 are hosted in olivines which lie within the equilibrium field
Detailed investigation of melt inclusion volatile systematics from the 2018 eruption of Kılauea reveal that the erupted crystal cargo originated from both the Halema’uma’u reservoir and the South Caldera reservoir
Summary
The 2018 lower East Rift Zone (LERZ) eruption was the largest and most destructive in the last 200 years of activity at Kılauea Volcano, Hawai’i (Neal et al, 2019), accompanied by the highest co-eruptive fluxes of SO2 ever measured at Kılauea (up to 200 kt a day; Kern et al, 2020; Whitty et al, 2020), and very high lava WIESER ET AL.Geochemistry, Geophysics, Geosystems effusion rates (100–300 m3/s; Neal et al, 2019; Patrick, Dietterich et al, 2019). The 2018 eruption was preceded by swarms of lower-crustal earthquakes at ∼6–12-km depth beneath Kılauea’s summit area on March 7, April 11, and April 18, 2018 (Flinders et al, 2020) This inflation has been variably interpreted to result from a short-term increase in magma supply (Flinders et al, 2020), or a decrease in the output of magma along the ERZ to PuuŌō, leading to magma backing up within the summit reservoir (Patrick et al, 2020). Inflationary ground deformation began at Pu‘uŌō, suggesting that excess magma was accumulating beneath this vent (Neal et al, 2019) The pressurization at these two locations continued throughout March and April, demonstrated by the rise of the lava pond at Pu‘uŌō, and overflows of the summit lava lake in mid-late April. 24 fissures opened between May 3 and May 27, 2018
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
