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Periodic dike intrusions in Kīlauea's middle East Rift Zone continue post-2018

Emily K. Montgomery-Brown1, Kyle Anderson1 , Ingrid A. Johanson2, Andria P. Ellis2, Michael P. Poland3

  • Affiliations: 1Cascades Volcano Observatory, U.S. Geological Survey, Vancouver, WA, USA. 2Hawaiian Volcano Observatory, U.S. Geological Survey, Hilo, HI, USA. 3Yellowstone Volcano Observatory, U.S. Geological Survey, Vancouver, WA, USA.

  • Presentation type: Talk

  • Presentation time: Monday 09:00 - 09:15, Room S160

  • Programme No: 2.4.3

  • Theme 2 > Session 4

Abstract

Intrusions and eruptions on segments of Kīlauea's East Rift Zone (ERZ) demonstrate periodic recurrence times correlating with the sliding velocity along the adjacent flank décollement (Montgomery-Brown and Miklius, 2021).  Persistent segmentation and regular recurrence intervals were discovered only by including both intrusions and eruptions. Middle ERZ segments demonstrate 14-year recurrence intervals with adjacent flank décollement slip rates of ~0.1 m/yr, whereas upper ERZ segments are less regular, but average ~8 years with higher adjacent flank slip rates of ~0.15 m/yr.  Lower ERZ periodicity is more difficult to constrain with substantially fewer observed events, longer interevent times, and much slower adjacent flank slip rates (<0.01 m/yr); however, historic records and previous eruptions indicate a recurrence interval of about 50 years (Denlinger and Morgan, 2014).  The regular recurrence intervals were initially thought to occur only during periods of open-system effusive eruptions, like the extended 35-year eruption of Pu'u'ō'ō.  The plumbing system was disrupted by the 2018 events -- including dike intrusion, eruption, and M6.9 earthquake -- that caused drastic changes to Kīlauea's behavior (e.g., periodic decollement slow slip events have not resumed, but flank slip velocities remain elevated).  In September 2024, a middle ERZ dike erupted in Nāpau crater in the same region as previous events (1997 and 2011), and on-schedule for the 14-year recurrence, despite large-scale disruptions in 2018. Persistent, periodic recurrence times of intrusions in Kīlauea's upper and middle ERZ segments through the 2018 events provide further evidence of the tight coupling between magma supply and flank deformation at Kīlauea.