Evolution of Seismicity During the 2018 Kīlauea Volcano Eruption

Date: 4/26/2019

Time: 08:30 AM

Room: Puget Sound

The 2018 eruption of Kīlauea Volcano began on April 30th, as Pu`u `Ō`ō vent collapsed and a trail of earthquakes marched towards the Lower East Rift Zone (LERZ). The subsequent withdrawal of the lava lake at Halema`uma`u began on May 1st, and the first of 24 eruptive fissures in the LERZ opened-up half a day before the M6.9 tectonic earthquake on May 4th.

Seismicity on the LERZ subsided when Fissure 8 became the dominant source of lava after May 27th, while a dozen explosive, very long period (VLPe) events with moment magnitudes of M4.7-5.1 occurred at Kīlauea summit at 8-45 hour intervals from May 16-26th. By the end of May, these explosive events transitioned into VLP collapse (VLPc) events, with moment magnitudes of M5.2-5.4 at almost-daily occurrences until August 5th. A total of 62 VLP events, and the swarms of smaller earthquakes in between, chronicle the largest collapse of the Kīlauea summit caldera in at least 200 years.

Bounding these keystone seismic events, from April 30th to August 5th, are unprecedented rates of seismicity that signal the migration of magma in conduits and/or failure of asperities on faults. The interplay between the volcanoseismic and tectonic events during the 2018 Kīlauea eruption sequence is poorly understood. In this preliminary work, we look at hypocentral locations, timing, and frequency content of over 60k detected events at this time period to better elucidate their source processes and triggering mechanisms, and ultimately, future hazard mitigation.

Presenting Author: Jefferson C. Chang

Authors