The Rheology of Crystallizing basaltic lavas from Nyiragongo and Nyamuragira volcanoes, D.R.C.

Main Article Content

Aaron Andrew Morrison
Alan Whittington
Benoît Smets
Matthieu Kervyn
Alexander Sehlke


Nyiragongo (Democratic Republic of Congo) erupts fluid, fast-moving, foidite lavas. Nearby Nyamuragira frequently erupts less mobile tephrite lavas. Nyamuragira flows rarely threaten urbanized areas, but Nyiragongo flows threaten Goma (pop. ~900,000) and surrounding villages, resulting in fatalities in 1977 and 2002. We report new laboratory measurements of viscosity evolution during cooling and crystallization from both volcanoes by concentric cylinder viscometry. Melt viscosity is ~33 Pa s at the liquidus (~1220°C) for Nyiragongo lavas, similar to Hawaiian basalts. Lavas remain fluid over ~75°C of undercooling (?c <0.05) before rapid crystallization forms a crystal network inhibiting flow. Melt viscosity is ~40 Pa s at the liquidus (~1260 C) for Nyamuragira lavas, which remain fluid over ~110 C of undercooling (?c <0.11) before the onset of rapid crystallization. Low viscosity allows thin Nyiragongo flows to reach >10 ms-1 even at subliquidus temperatures on low slopes, posing great risk to Goma.


Download data is not yet available.

Article Details

How to Cite
Morrison, A. A., Whittington, A., Smets, B., Kervyn, M. and Sehlke, A. (2020) “C”., Volcanica, 3(1), pp. 1–28. doi: 10.30909/vol.03.01.0128.
Citation information
This article has citations in Scopus
Link to article page on Google Scholar
Connected papers
Received 2019-04-23
Accepted 2019-12-18
Published 2020-02-09
Alternative metrics via Dimensions and altmetric


Smart Citations via scite_