Tracking formation of a lava lake from ground and space: Masaya volcano (Nicaragua), 2015-2017
Journal article, 2018
A vigorously degassing lava lake appeared inside the Santiago pit crater of Masaya volcano (Nicaragua) in December 2015, after years of degassing with no (or minor) incandescence. Here, we present an unprecedented-long (3 years) and continuous volcanic gas record that instrumentally characterizes the (re)activation of the lava-lake. Our results show that, before appearance of the lake, the volcanic gas plume composition became unusually CO2-rich, as testified by high CO2/SO2 ratios (mean, 12.2±6.3) and low H2O/CO2 ratios (mean, 2.3±1.3). The volcanic CO2 flux also peaked in November 2015 (mean, 81.3±40.6 kg/s; maximum, 247 kg/s). Using results of magma degassing models and budgets, we interpret this elevated CO2 degassing as sourced by degassing of a volatile-rich fast-convecting (3.6-5.2 m3·s-1) magma, supplying CO2-rich gas bubbles from minimum equivalent depths of 0.36-1.4 km. We propose this elevated gas bubbles supply destabilized the shallow (<1 km) Masaya magma reservoir, leading to upward migration of vesicular (buoyant) resident magma, and ultimately to (re)formation of the lava lake. At onset of lava lake activity on 11 December 2015 (constrained by satellite-based (MODIS) thermal observations), the gas emissions transitioned to more SO2-rich composition, and the SO2 flux increased by a factor ~40 % (11.4±5.2 kg/s) relative to background degassing (8.0 kg/s), confirming faster than normal (4.4 vs. ~3 m3·s-1) shallow magma convection. Elevated shallow magma circulation is also supported by gradual increase in irradiated thermal energy, captured by MODIS, from which we calculate that 0.4-0.8 m3·s-1 of magma have been surface-emplaced since December 2015.
Author
Sandro Aiuppa
National Institute of Geophysics and Volcanology
University of Palermo
Martin de Moor
National University Costa Rica
Santiago Arellano
Chalmers, Space, Earth and Environment, Microwave and Optical Remote Sensing
D. Coppola
University of Turin
Vincenzo Francofonte
National Institute of Geophysics and Volcanology
Bo Galle
Chalmers, Space, Earth and Environment, Microwave and Optical Remote Sensing
G. Giudice
National Institute of Geophysics and Volcanology
Marco Liuzzo
National Institute of Geophysics and Volcanology
Elvis Mendoza
Instituto Nicaragüense de Estudios Territoriales
Armando Saballos
Instituto Nicaragüense de Estudios Territoriales
Giancarlo Tamburello
University of Palermo
National Institute of Geophysics and Volcanology
Angelo Battaglia
University of Palermo
Marcello Bitetto
University of Palermo
Sergio Gurrieri
National Institute of Geophysics and Volcanology
Marco Laiolo
University of Florence
Andrea Mastrolia
National Institute of Geophysics and Volcanology
Roberto Moretti
Second University of Naples
Geochemistry, Geophysics, Geosystems
15252027 (eISSN)
Vol. 19 2 496-515Roots
Basic sciences
Subject Categories
Earth and Related Environmental Sciences
DOI
10.1002/2017GC007227