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

Istituto Nazionale di Geofisica e Vulcanologia

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

Istituto Nazionale di Geofisica e Vulcanologia

Bo Galle

Chalmers, Space, Earth and Environment, Microwave and Optical Remote Sensing

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

University of Palermo

Istituto Nazionale di Geofisica e Vulcanologia

Angelo Battaglia

University of Palermo

Marcello Bitetto

University of Palermo

Sergio Gurrieri

Istituto Nazionale di Geofisica e Vulcanologia

Marco Laiolo

University of Florence

Andrea Mastrolia

Istituto Nazionale di Geofisica e Vulcanologia

Roberto Moretti

Second University of Naples

Geochemistry, Geophysics, Geosystems

1525-2027 (ISSN)

Roots

Basic sciences

Subject Categories

Earth and Related Environmental Sciences

DOI

10.1002/2017GC007227

More information

Latest update

4/13/2018