Gravity‐driven deformation of Tenerife measured by InSAR time series analysis

Abstract

We study the state of deformation of Tenerife (Canary Islands) using Differential Synthetic Aperture Radar Interferometry (DInSAR). We apply the Small BAseline Subset (SBAS) DInSAR algorithm to radar images acquired from 1992 to 2005 by the ERS sensors to determine the deformation rate distribution and the time series for the coherent pixels identified in the island. Our analysis reveals that the summit area of the volcanic edifice is characterized by a rather continuous subsidence extending well beyond Las Cañadas caldera rim and corresponding to the dense core of the island. These results, coupled with GPS ones, structural and geological information and deformation modeling, suggest an interpretation based on the gravitational sinking of the dense core of the island into a weak lithosphere and that the volcanic edifice is in a state of compression. We also detect more localized deformation patterns correlated with water table changes and variations in the deformation time series associated with the seismic crisis in 2004.

An Overview of Geodetic Volcano Research in the Canary Islands

“…Some deformation at surface has been detected, associated to this reactivation, using GNSS (see Figure 8) and InSAR (see Figure 10) observations and described in different works (González et al, 2005;Prieto et al, 2005;Fernández et al, 2006Fernández et al, , 2007Samsonov et al, 2008;Fernández et al, 2009;González et al, 2010a;Tizzani et al, 2010 ENVISAT data was performed with GAMMA software. All possible combinations were used to create interferograms and then stacking was used to increase signal-to-noise ratio.…”

“…These 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 results, coupled with GPS ones, structural and geological information and deformation modeling, suggest an interpretation based on the gravitational sinking of the dense core of the island into a weak lithosphere and that the volcanic edifice is in a state of compression. Fernández et al (2009) also detect more localized deformation patterns, some of them previously detected using classical…”

“…covering complete Islands (Carrasco et al, 2000a;, with high spatial resolution and, in after a few years, precision (Fernández et al, 2009;González and Fernández, 2011). Both events drastically changed, the geodetic monitoring of volcanic activity worldwide and in particular for the Canary Islands.…”

“…In the 21st century, several gravimetric works (sometimes complemented with microseismic experiments) have sought to better define gravity anomalies and show structural details on different islands such as Lanzarote (Camacho et al, 2001;Gorbatikov et al, 2004), -García et al, 2007;Gottsmann et al, 2008;Camacho et al, 2011a, b), Fuerteventura (Montesinos et al, 2005), La Palma (Camacho et al, 2009), El Hierro (Montesinos et al, 2006;Gorbatikov et al, 2013), and La Gomera (Montesinos et al, 2011. ), and in the vicinity of the Canary Islands (Llanes, 2006).…”

“…For example, for La Palma the following characteristics can be described (Camacho et al, 2009): a large body of high density in the northern half corresponding to ancient volcanism massive; a high-density structure elongated along the NS rift in the middle; and lower densities in the south and on both sides of the central rift, associated to fracturing, to light recent volcanic deposits and zones of very recent activity (as Teneguia volcano at the south end of the Island).…”