Stress and mass changes at a “wet” volcano: Example during the 2011–2012 volcanic unrest at Kawah Ijen volcano (Indonesia)

Abstract

Since 2010, Kawah Ijen volcano has been equipped with seismometers, and its extremely acid volcanic lake has been monitored using temperature and leveling sensors, providing unprecedented time resolution of multiparametric data for an acidic volcanic lake. The nature of stress and mass changes of the volcano is studied by combining seismic analyses and volcanic lake measurements that were made during the strongest unrest ever recorded by the seismic network at Kawah Ijen. The distal VT earthquake swarm that occurred in May 2011 was the precursor of volcanic unrest in October 2011 that caused an increase in shallow earthquakes. The proximal VT earthquakes opened pathways for fluids to ascend by increasing the permeability of the rock matrix. The following months were characterized by two periods of strong heat and mass discharge into the lake and by the initiation of monochromatic tremor (MT) activity when steam/gases interacted with shallow portions of the aquifer. Significant seismic velocity variations, concurrent with water level rises in which water contained a large amount of steam/gas, were associated with the crises, that caused an although the unrest did not affect the shallow hydrothermal system at a large scale. Whereas shallow VT earthquakes likely reflect a magmatic intrusion, MT and relative seismic velocity changes are clearly associated with shallow hydrothermal processes. These results will facilitate the forecast of future crises.

Kawah Ijen volcanic activity: a review

“…After relatively constant temperatures, the temperature pattern is not stable anymore and is affected by sharp drops and increases until the 17th of March. This period coincides with a strong unrest evidenced by the seismometers (Caudron et al 2014).…”

“…After this period, the activity diminished until July 2012 which was characterized by a high record of LFs. This crisis is studied in details in (Caudron et al 2014). Figure 30 portrays the lake temperature evolution between May 2010 and July 2012.…”

Decrease in Seismic Velocity Observed Prior to the 2018 Eruption of Kīlauea Volcano With Ambient Seismic Noise Interferometry

“…Ambient noise studies do not require an active source or repeating earthquakes and have been successfully applied to measure changes in seismic velocity in a range of different environments, such as volcanoes Donaldson et al, 2017;Sánchez-Pastor et al, 2018;Sens-Schönfelder & Wegler, 2006), landslides (Mainsant et al, 2012), underground mines , geothermal reservoirs (Hillers et al, 2015;Obermann et al, 2015), active faults zones , earthen dams (Olivier et al, 2017;Planès et al, 2015), and other environments. Notably, it has been shown that a detectable change in seismic velocity occurs in the days leading up to an eruption at some volcanoes (Bennington et al, 2015;Budi-Santoso & Lesage, 2016;Caudron et al, 2015;Grêt et al, 2005;Hirose et al, 2017;Patanè et al, 2006;Ratdomopurbo & Poupinet, 1995;Wegler et al, 2006). These virtual source signals can be constructed at different times, so small temporal changes in seismic velocity can be measured to study processes in the Earth's crust.…”

Response of hydrothermal system to stress transients at Lassen Volcanic Center, California, inferred from seismic interferometry with ambient noise

“…In the last several years, seismic interferometry has become one of the most effective seismological tools for time-lapse monitoring of hydrothermal and magmatic reservoirs (e.g., Brenguier et al 2008bBrenguier et al , 2011Brenguier et al , 2016Haney et al 2009;Nagaoka et al 2010;Jaxybulatov et al 2014;Caudron et al 2015;Spica et al 2015). Here, we apply seismic interferometry to continuous seismic recordings for investigating the temporal seismic behavior of the Lassen hydrothermal system.…”