Plume composition and volatile flux of Nyamulagira volcano, Democratic Republic of Congo, during birth and evolution of the lava lake, 2014–2015
Journal article, 2017

Very little is known about the volatile element makeup of the gaseous emissions of Nyamulagira volcano. This paper tries to fill this gap by reporting the first gas composition measurements of Nyamulagira’s volcanic plume since the onset of its lava lake activity at the end of 2014. Two field surveys were carried out on 1 November 2014, and 13–15 October 2015. We applied a broad toolbox of volcanic gas composition measurement techniques in order to geochemically characterize Nyamulagira’s plume. Nyamulagira is a significant emitter of SO2, and our measurements confirm this, as we recorded SO2 emissions of up to ~ 14 kt/d during the studied period. In contrast to neighbouring Nyiragongo volcano, however, Nyamulagira exhibits relatively low CO2/SO2 molar ratios (< 4) and a high H2O content (> 92% of total gas emissions). Strong variations in the volatile composition, in particular for the CO2/SO2 ratio, were measured between 2014 and 2015, which appear to reflect the simultaneous variations in volcanic activity. We also determined the molar ratios for Cl/S, F/S and Br/S in the plume gas, finding values of 0.13 and 0.17, 0.06 and 0.11, and 2.3·10?4 and 1·10?4, in 2014 and 2015, respectively. A total gas emission flux of 48 kt/d was estimated for 2014. The I/S ratio in 2015 was found to be 3.6·10?6. In addition, we were able to distinguish between hydrogen halides and non-hydrogen halides in the volcanic plume. Considerable amounts of bromine (18–35% of total bromine) and iodine (8–18% of total iodine) were found in compounds other than hydrogen halides. However, only a negligible fraction of chlorine was found as compounds other than hydrogen chloride.

Total gas flux

Nyamulagira

Plume composition

Author

N. Bobrowski

Johannes Gutenberg University Mainz

Heidelberg University

G. B. Giuffrida

Istituto Nazionale di Geofisica e Vulcanologia

Santiago Arellano

Microwave and Optical Remote Sensing

M. Yalire

OVG

M. Liotta

Istituto Nazionale di Geofisica e Vulcanologia

L. Brusca

Istituto Nazionale di Geofisica e Vulcanologia

S. Calabrese

Dipartimento STeMBio

S. Scaglione

Dipartimento STeMBio

J. Rüdiger

Technische Universität Dortmund

J. M. Castro

Johannes Gutenberg University Mainz

Bo Galle

Microwave and Optical Remote Sensing

D. Tedesco

Istituto Nazionale di Geofisica e Vulcanologia

University of Campania Luigi Vanvitelli

Bulletin of Volcanology

0258-8900 (ISSN) 1432-0819 (eISSN)

Vol. 79 12 90- 90

Subject Categories

Earth and Related Environmental Sciences

DOI

10.1007/s00445-017-1174-0

More information

Latest update

6/12/2018