Bulletin of Volcanology

, Volume 74, Issue 1, pp 107–117

Lava channel roofing, overflows, breaches and switching: insights from the 2008–2009 eruption of Mt. Etna


    • Lancaster Environment CentreLancaster University
  • L. Jane Applegarth
    • Lancaster Environment CentreLancaster University
  • Harry Pinkerton
    • Lancaster Environment CentreLancaster University
Research Article

DOI: 10.1007/s00445-011-0513-9

Cite this article as:
James, M.R., Applegarth, L.J. & Pinkerton, H. Bull Volcanol (2012) 74: 107. doi:10.1007/s00445-011-0513-9


During long-lived basaltic eruptions, overflows from lava channels and breaching of channel levées are important processes in the development of extensive 'a'ā lava flow-fields. Short-lived breaches result in inundation of areas adjacent to the main channel. However, if a breach remains open, lava supply to the original flow front is significantly reduced, and flow-field widening is favoured over lengthening. The development of channel breaches and overflows can therefore exert strong control over the overall flow-field development, but the processes that determine their location and frequency are currently poorly understood. During the final month of the 2008–2009 eruption of Mt. Etna, Sicily, a remote time-lapse camera was deployed to monitor events in a proximal region of a small ephemeral lava flow. For over a period of ~10 h, the flow underwent changes in surface elevation and velocity, repeated overflows of varying vigour and the construction of a channel roof (a required prelude to lava tube formation). Quantitative interpretation of the image sequence was facilitated by a 3D model of the scene constructed using structure-from-motion computer vision techniques. As surface activity waned during the roofing process, overflow sites retreated up the flow towards the vent, and eventually, a new flow was initiated. Our observations and measurements indicate that flow surface stagnation and flow inflation propagated up-flow at an effective rate of ~6 m h−1, and that these processes, rather than effusion rate variations, were ultimately responsible for the most vigorous overflow events. We discuss evidence for similar controls during levée breaching and channel switching events on much larger flows on Etna, such as during the 2001 eruption.


BasaltLava channelLava flow fieldOverflowsLevée breachMt. EtnaLava tube

Supplementary material

445_2011_513_MOESM1_ESM.mp4 (36.7 mb)
Online Resource 1A video file constructed from excerpts of the time-lapse images, covering the active lava flows. For detailed viewing, we recommend advancing frame by frame (MP4 37590 kb)
View video
Online Resource 2

A video animation ‘fly through’ of the 3D model of the T1 and F1 area. The animation starts and ends observing the scene vertically, as shown in Fig. 1b (MP4 49547 kb)

Copyright information

© Springer-Verlag 2011