The cascading origin of the 2018 Kīlauea eruption and implications for future forecasting

Abstract

The 2018 summit and flank eruption of Kīlauea Volcano was one of the largest volcanic events in Hawaiʻi in 200 years. Data suggest that a backup in the magma plumbing system at the long-lived Puʻu ʻŌʻō eruption site caused widespread pressurization in the volcano, driving magma into the lower flank. The eruption evolved, and its impact expanded, as a sequence of cascading events, allowing relatively minor changes at Puʻu ʻŌʻō to cause major destruction and historic changes across the volcano. Eruption forecasting is inherently challenging in cascading scenarios where magmatic systems may prime gradually and trigger on small events.

Reconstructing Magma Storage Depths for the 2018 Kı̄lauean Eruption From Melt Inclusion CO2 Contents: The Importance of Vapor Bubbles

“…These new melts (along with the high‐Fo olivines they scavenged) would then have mixed into the cooler, lower Mg# melts present within the middle to upper parts of the SC reservoir. Alternatively, if inflationary signals were generated by a reduction in the amount of magma flowing along the ERZ to Pu‘u ’Ō’ō (Patrick et al., 2020), progressive internal pressurization of the SC reservoir could also disturb piles of settled crystals. Rapid cooling of mush‐derived olivines following their mixing into more evolved melts would have initiated large amounts of PEC.…”

“…If the disturbance to the mush pile was solely the result of pressurization of the volcanic plumbing system, it might be expected that the majority of high‐Fo olivines were disturbed from their mush piles in mid‐March to April 2019, when inflationary signals were the strongest (Neal et al., 2019; Patrick et al., 2020). In this scenario, high‐Fo olivines might be expected to be more dominant in the May 2018 versus July and August 2018 samples.…”

“…Alternatively, if inflationary signals were generated by a reduction in the amount of magma flowing along the ERZ to Pu'u 'Ō'ō (Patrick et al, 2020), progressive internal pressurization of the SC reservoir could also disturb piles of settled crystals. Rapid cooling of mush-derived olivines following their mixing into more evolved melts would have initiated large amounts of PEC.…”

“…The 2018 eruption was preceded by swarms of lower‐crustal earthquakes at ∼6–12‐km depth beneath Kı̄lauea’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 Puʻu ʻŌʻō, leading to magma backing up within the summit reservoir (Patrick et al., 2020). On March 13, 2018, inflation was recorded by tiltmeters located at Kı̄lauea’s summit.…”

Ongoing (2015‐) Magma Surge in the Upper Mantle Beneath the Island of Hawaiʻi

“…However, the PMFZ intrusion is primarily characterized by a strong and persistent increase in the rate of mantle-depth VT earthquakes over 2015 to present, while the 2003-2007 mantle surge produced only mantle-depth DLP seismicity beneath Mauna Loa. Geochemically, the 2003-2007 mantle surge was primarily characterized by an increase (more than double) in CO 2 emissions in 2003-2004, but CO 2 emission rates "were not available in the years immediately prior to 2018 due to challenging measurement geometry" (Patrick et al, 2020 (Greene et al, 2013), and MgO contents between 2015 and 2018 were consistent with long-term values at Pu'u 'Ō'ō (Gansecki et al, 2019). However isotopic variations during the Pu'u 'Ō"ō eruption have been interpreted to indicate the magma erupted during the 2003-2007 surge was new mantle-derived magma (Greene et al, 2013).…”