Characterization of volcanic materials using ground penetrating
radar: A case study at Teide volcano (Canary Islands, Spain)
, S. Martı´n-Vela´zquez, T. Martı´n-Crespo,
A. Ma´rquez, J. Lillo, I. Lo´pez, F. Carren˜o
rea de Geologı´a, Dpto. de Matema´ticas y Fı´sica Aplicadas y CC. de la Naturaleza, ESCET,
Universidad Rey Juan Carlos, C/Tulipa´n s/n, 28933 Mo´stoles (Madrid), Spain
Received 26 January 2005; accepted 20 July 2005
Ground penetrating radar (GPR) is a useful geophysical technique that can be used to characterize the nature, geometry and
spatial distribution of subsurface volcanic materials, being these valuable data to complete field observations in those areas
where information obtained from the surface is restricted. We have analyzed the GPR response in several volcanic materials
(massive and heterogeneous lava flows, pahoehoe and aa lava flows, airfall deposits and a dyke) occurring in the Teide volcano
and the Las Can˜adas edifice (Tenerife, Canary Islands, Spain), in order to recognize their occurrence and characterize their
thickness, spatial distribution, internal structures and discontinuities, as well as to evaluate the mean velocities of the
electromagnetic waves in these rocks and deposits. The obtained GPR profiles show that, depending on the nature of the
materials, the geometry of the reflectors is distinctive. The GPR reflectors of airfall pumice are thin, well-layered and laterally
continuous. In contrast, different lava flows, as well as dykes, originate a different radar response. When alternating massive
and scoriaceous beds in lava flows are present, the reflectors are characterized by an undulate and laterally discontinuous
geometry. Regarding the pahoehoe lava flows, their radar signature is defined by well defined reflectors. The aa lava flows
exhibit weak reflectors. Massive and homogeneous lava flows and dykes are resolved as massive structures with scarce or
absent internal reflections. The mean velocity of the electromagnetic waves through the different deposits ranges from 0.07 to
0.12 m ns
. As a general approximation, the velocity of the electromagnetic waves is faster in lava flows that in airfall
deposits, where attenuation is greater and penetration depth is lower. The estimation of the propagation velocity for the
electromagnetic waves has allowed us to process the profiles and to carry out depth–time conversions and migration, in order to
get more realistic 2-D representations.
D 2005 Elsevier B.V. All rights reserved.
Keywords: GPR; Tenerife; Airfall deposits; Lava flows; Dykes; EM waves velocity
0926-9851/$ - see front matter D 2005 Elsevier B.V. All rights reserved.
* Corresponding author. Tel.: +34 91 488 70 92; fax: +34 91 664 74 90.
E-mail address: email@example.com (D. Go´ mez-Ortiz).
Journal of Applied Geophysics 59 (2006) 63 – 78