Topographic and stochastic influences on pāhoehoe lava lobe emplacement

Christopher W Hamilton, Lori S. Glaze, Mike R. James, Stephen M. Baloga

Research output: Contribution to journalArticle

26 Scopus citations

Abstract

A detailed understanding of pāhoehoe emplacement is necessary for developing accurate models of flow field development, assessing hazards, and interpreting the significance of lava morphology on Earth and other planetary surfaces. Active pāhoehoe lobes on Kīlauea Volcano, Hawai'i, were examined on 21-26 February 2006 using oblique time series stereo-photogrammetry and differential global positioning system measurements. During this time, the local discharge rate for peripheral lava lobes was generally constant at 0.0061 ± 0.0019 m3/s, but the areal coverage rate of the lobes exhibited a periodic increase every 4.13 ± 0.64 min. This periodicity is attributed to the time required for the pressure within the liquid lava core to exceed the cooling-induced strength of its margins. The pāhoehoe flow advanced through a series of down-slope and cross-slope breakouts, which began as ∼0.2-m-thick units (i.e., toes) that coalesced and inflated to become approximately meter-thick lobes. The lobes were thickest above the lowest points of the initial topography and above shallow to reverse-facing slopes, defined relative to the local flow direction. The flow path was typically controlled by high-standing topography, with the zone directly adjacent to the final lobe margin having an average relief that was a few centimeters higher than the lava-inundated region. This suggests that toe-scale topography can, at least temporarily, exert strong controls on pāhoehoe flow paths by impeding the lateral spreading of the lobe. Observed cycles of enhanced areal spreading and inflated lobe morphology are also explored using a model that considers the statistical likelihood of sequential breakouts from active flow margins and the effects of topographic barriers.

Original languageEnglish (US)
Pages (from-to)1-16
Number of pages16
JournalBulletin of Volcanology
Volume75
Issue number11
DOIs
Publication statusPublished - Nov 2013
Externally publishedYes

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Keywords

  • Lobe emplacement
  • Pāhoehoe lava
  • Stochastic processes
  • Topographic influences

ASJC Scopus subject areas

  • Geochemistry and Petrology

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