HR: 1340h
AN: V53C-1423    [Abstracts]
TI: Ground deformation in La Palma (Canary Islands) detected using Stacking Radar Interferometry
AU: * Fernandez, J
EM: jose_fernandez@mat.ucm.es
AF: Instituto de Astronomia y Geodesia (CSIC-UCM), Fac. C. Matematicas, Ciudad Universitaria, Plaza de Ciencias, 3., Madrid, 28040, Spain
AU: Gonzalez, P J
EM: pjgonzal@mat.ucm.es
AF: Instituto de Astronomia y Geodesia (CSIC-UCM), Fac. C. Matematicas, Ciudad Universitaria, Plaza de Ciencias, 3., Madrid, 28040, Spain
AU: Tiampo, K F
EM: ktiampo@seis.es.uwo.ca
AF: Department of Earth Sciences, University of Western Ontario, London, Ont N6A 5B7, Canada
AU: Perlock, P A
EM: oaoerloc@uwo.ca
AF: Department of Earth Sciences, University of Western Ontario, London, Ont N6A 5B7, Canada
AU: Camacho, A G
EM: antonio_camacho@mat.ucm.es
AF: Instituto de Astronomia y Geodesia (CSIC-UCM), Fac. C. Matematicas, Ciudad Universitaria, Plaza de Ciencias, 3., Madrid, 28040, Spain
AB: Ground deformation in ocean volcanic islands can reveal deep accommodation of strain at depth due to very different mechanisms. Nowadays, volcano-tectonics and its relation to volcanic activity is a very open research field. Using InSAR measurements, we are able to detect transient and/or persistent patterns of deformation in this kind of volcanic environments. We have studied an 8-year period (1992-2000) using ERS-1/2 SAR images over the island of La Palma, Canary Islands. First, single interferograms have not shown significant deformation over several cycles (or fringes), and second, La Palma is located in a tropical area so interferometric phase measurements would be greatly affected with the existence of tropospheric water vapour and dense vegetation. In order to mitigate those effects, we use a total number of 48 interferogram to obtain a stacked (average) velocity map of the surface deformation covering most of the island, where coherence is preserved. We found two areas of deformation. First, a subsidence signal around 5-6 mm/yr is located in the southern tip of the island in the area of 1971-Teneguia volcano (a recent cinder cone and lava flows). Second, a broader subsidence area around 3-4 mm/yr is located covering the western of the Cumbre Vieja volcano. We present preliminar modelling results about the causative sources. Ground deformation using InSAR is an important tool to reveal the actual state of strain at the surface in an oceanic volcanic island and using jointly with mathematical modelling is able to infer useful information about deep processes in and below the volcanic edifice.
DE: 1240 Satellite geodesy: results (6929, 7215, 7230, 7240)
DE: 8419 Volcano monitoring (7280)
DE: 8485 Remote sensing of volcanoes
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting