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Remote Measurements of Lava Flux at Arenal and Soufrière Hills Volcanoes using AVTIS. G. Wadge 1 , D.G. Macfarlane 2 , M. James 3 , D.A. Robertson 2 , H. Pinkerton 3 , H. Odbert 1 and L.J.Applegarth 3. 1. ESSC, University of Reading
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Remote Measurements of Lava Flux at Arenal and Soufrière Hills Volcanoes using AVTIS G. Wadge1, D.G. Macfarlane2, M. James3, D.A. Robertson2, H. Pinkerton3, H. Odbert1 and L.J.Applegarth3 1. ESSC, University of Reading 2. School of Physics and Astronomy, University of St. Andrews 3. Environment Centre, Lancaster University OVSICORI UNA
Prototype AVTIS Field Instrument Instrument • FMCW 94 GHz radar • 0.3 m Antenna • Pan & Tilt Positioner • Laptop Control • 2 Car Batteries • 1m range resolution • 2 K temperature resolution • Spot size radar =9 m/ km • Spot size radiom.=12/ km • Imaging rate = 4 pixels/sec.
WEST FLOW SOUTH FLOW Arenal, Costa Rica: April 2005 Low effusion rate basaltic andesite lava flows from the summit
Reflected power (dBr) Arenal: Radar Surveyed Topography
Arenal South Flow, from Southwest 24/04/05
Arenal South Flow, from Southwest 28/04/05
Arenal South Flow, from Southwest 30/04/05
Arenal SouthLava Flow: Volume changes gives extrusion rates Extrusion Rates Southwest view Day 2 to 8 = 0.23 +/- 0.04 m3/s Day 2 to 6 = 0.18 +/- 0.05 m3/s Day 6 to 8 = 0.34 +/- 0.07 m3/s South View Day 1 to 5 = 0.28 +/- 0.13 m3/s Day 5 to 9 = 0.15 +/- 0.05 m3/s Day 1 to 9 = 0.22 +/- 0.09 m3/s South View Height Changes Day 1-5 Day 5-9 Day 1-9
… and change shape … Soufrière Hills, Montserrat Collapsing dome, often hidden by clouds
Montserrat,Perche’s viewpoint: 25 Oct., 2005 AVTIS DEM Photo
Vertical surface height change:25 Oct. - 4 Nov. 2005 Extrusion Rate: 1.1 ± 0.1 m3s-1
4 Nov. 2005 thermal images of the Soufriere Hills lava dome IR AVTIS mm-wave radiometer FLIR IR camera
4 Nov. 2005 thermal images of the Soufriere Hills lava dome IR
Conclusions • AVTIS radar and radiometer tested through cloud out to 7 km • At Arenal, 15 m thick basaltic andesite flows were measured over 8 days from a range of 3 km giving a flux of 0.2 ± 0.08 m3s-1 • At Soufrière Hills, endogenous andesitic dome growth was measured over 10 days from a range of 1.2 km giving a flux of 1.1 ± 0.1 m3 s-1