Tracking formation of a lava lake from ground and space: Masaya volcano (Nicaragua), 2015-2017
Artikel i vetenskaplig tidskrift, 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.
Författare
Sandro Aiuppa
Istituto Nazionale di Geofisica e Vulcanologia
Universita degli Studi di Palermo
Martin de Moor
Universidad Nacional de Costa Rica
Santiago Arellano
Chalmers, Rymd-, geo- och miljövetenskap, Mikrovågs- och optisk fjärranalys
D. Coppola
Universita degli Studi di Torino
Vincenzo Francofonte
Istituto Nazionale di Geofisica e Vulcanologia
Bo Galle
Chalmers, Rymd-, geo- och miljövetenskap, Mikrovågs- och optisk fjärranalys
G. Giudice
Istituto Nazionale di Geofisica e Vulcanologia
Marco Liuzzo
Istituto Nazionale di Geofisica e Vulcanologia
Elvis Mendoza
Instituto Nicaragüense de Estudios Territoriales
Armando Saballos
Instituto Nicaragüense de Estudios Territoriales
Giancarlo Tamburello
Universita degli Studi di Palermo
Istituto Nazionale di Geofisica e Vulcanologia
Angelo Battaglia
Universita degli Studi di Palermo
Marcello Bitetto
Universita degli Studi di Palermo
Sergio Gurrieri
Istituto Nazionale di Geofisica e Vulcanologia
Marco Laiolo
Universita degli Studi di Firenze
Andrea Mastrolia
Istituto Nazionale di Geofisica e Vulcanologia
Roberto Moretti
Seconda Universitet degli Studi di Napoli
Geochemistry, Geophysics, Geosystems
15252027 (eISSN)
Vol. 19 2 496-515Fundament
Grundläggande vetenskaper
Ämneskategorier
Geovetenskap och miljövetenskap
DOI
10.1002/2017GC007227