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

1525-2027 (ISSN)

Fundament

Grundläggande vetenskaper

Ämneskategorier

Geovetenskap och miljövetenskap

DOI

10.1002/2017GC007227