Deformation of volcanoes measured by InSAR

InSAR (Interferometry of Synthetic Aperture Radar data) is used to obtain maps of surface displacements in volcanic areas. Displacements are induced by magma transport and storage at shallow depth, loading due to eruptive deposits emplacement or volcanoes instabilities. They are used to image magmatic storage zones.

Figure 1 : Deformation at Colima Volcano (Mexico) from 2002 to 2006 obtained by ENVISAT data. Mean velocity in LOS in mm/year for the summit area of Colima Volcano (positive values are for displacements directed towards the satellite). Results are superimposed on the SRTM Digital Elevation Model. Black boxes are for the area of reference where the mean velocity is arbitrarily set to zero. a) Mean velocity obtained for the descending track 384. b) Mean velocity obtained for the ascending track 48. Displacements can be modeled considering both a uniform circular load of 1.3 Mm3/y with a 0.5 km radius and a Mogi deflating source at 2.5 km depth with ΔV=0.23*106m3/y. NCV : Nevado de Colima Volcano, CV : Colima Volcano. The outline of the 1998 lava flow is reported in panel a). (from Pinel et al, 2011).

Figure 2 : Deformation at Colima Volcano (Mexico) from 2007 to 2010 obtained by ALOS data. Superposition of the mean velocity obtained using the ascending track 195 on the Google Earth image. The red line is for 6.5 km. One cycle of color is for a velocity of 2.7 cm/y.