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Formation of channelized lava flows on an unconfined slope

Date

2006

Authors

Kerr, Ross
Griffiths, Ross
Cashman, Katharine

Journal Title

Journal ISSN

Volume Title

Publisher

American Geophysical Union

Abstract

The formation of channelized lava flows on a wide uniform slope is investigated both theoretically and experimentally. When a lava is released at a constant flow rate from a point source, we predict that it flows both down and across the slope at the same rate in a early time regime before undergoing a transition to a long-time regime where down-slope flow is faster than lateral flow. Eventually, the lateral flow is stopped by the strength of the growing surface crust, and the flow then travels down slope in a channel of constant width. Using scaling analysis, we derive expressions for the final channel width in both flow regimes, as a function of the flow rate, the slope, the density difference driving the flow, the lava viscosity, the thermal diffasivity, and the yield strength of the crust. We also find a dimensionless flow morphology parameter that controls whether the subsequent channel flow occurs in a "mobile crust" regime or in a "tube" regime. These theoretical predictions are in good agreement with laboratory experiments in which polyethylene glycol wax flows down a wide uniform slope under cold water. The theory is also applied to the understanding of the formation of a basaltic sheet flow lobe in Hawaii, which had an estimated crust yield strength of order 6 × 104 Pa. Coyright 2006 by the American Geophysical Union.

Description

Keywords

Keywords: channel flow; lava flow; sheet flow; slope

Citation

Source

Journal of Geophysical Research

Type

Journal article

Book Title

Entity type

Access Statement

License Rights

DOI

10.1029/2005JB004225

Restricted until

2037-12-31