Geophysical Research Abstracts
Vol. 20, EGU2018-14285, 2018
EGU General Assembly 2018
© Author(s) 2018. CC Attribution 4.0 license.
Reconstructing the subsurface of planetary volcanic analogues: ERT
imaging of Lanzarote lava tubes complemented with drone
stereogrammetry, surface and in-cave LiDAR and seismic investigations
Patrizio Torrese (1), Angelo Pio Rossi (2), Vikram Unnithan (2), Dorit Borrmann (3), Helge Lauterbach (3),
Gianluigi Ortenzi (4), Tim Jährig (2), Riccardo Pozzobon (5), Francesco Sauro (6), Tommaso Santagata (7),
Andreas Nuechter (3), and Frank Sohl (4)
(1) Università di Pavia, Dipartimento di Scienze della Terra e dell’Ambiente, Pavia, Italy (email@example.com), (2)
Jacobs University Bremen, Physics and Earth Sciences, Bremen, Germany, (3) Julius-Maximilians-Universität Würzburg,
Würzburg, Germany, (4) DLR, Institute for Planetary Research, Berlin, Germany, (5) Università di Padova, Padova, Italy, (6)
Università di Bologna, Bologna, Italy, (7) VIGEA - Virtual Geographic Agency, Reggio Emilia, Italy
The study of planetary volcanic analogues through the application of geophysical methods is an important prepara-
tory step towards planetary subsurface exploration [e.g. 1, 2]. Within the recent ESA (European Space Agency)
astronaut training campaign extension PANGAEA-X  held in Lanzarote (Canary Islands), the Augmented ﬁeld
Geology and Geophysics for Planetary Analogues (AGPA) project [4, 5] was aimed at integrating training data
collection and analogue ﬁeld geology procedures with geophysical in-situ and remote sensing methods.
The geophysical campaign included ERT (Electrical Resistivity Tomography) surveys, drone stereogrammetry
, surface and in-cave LiDAR (Light Detection and Ranging) and seismic investigations. ERT surveys provided
the resistivity imaging of lava tubes in two sites located along the Corona volcano system. ERT has been proven to
be successfully in detecting and locating lava tubes and achieving a correct estimation of their size and depth and
provided a good deﬁnition of the boundaries between different volcanic units. The width of lava tubes varies from
10 to 20 m with depth less than 20 m in the investigated areas. The highest resistivity values (> 800–1000 Ωm)
correspond to lava tubes and cavities, intermediate resistivity values (∼100–800 Ωm) are related to massive and
consolidated materials (mainly lava ﬂows) and the lowest resistivity values (5–50 Ωm) correspond to different
types of non-consolidated volcanic deposits (mainly pyroclastic or explosive deposits).
In one test site, the reliability of ERT imaging in detecting lava tubes was veriﬁed by comparison with the true
imaging obtained from surface and in-cave LiDAR. The resistivity imaging was also compared to the seismic
imaging obtained from very light reﬂection and refraction surveys.
In the other test site, the presence of lava tubes is proven by the evidence of collapsed features (jameos or
sinkholes) aligned on the ground surface. Drone stereogrammetry provided the DTM (Digital Terrain Model) of
the area used for ERT imaging calibration. An assessment of seismic noise level provided early results on the
effectiveness of seismic noise measurements for the detection of lava tubes.
The integrated use of ERT and other geophysical investigations has been proven to be an effective approach for
the detection of planetary analogue targets, such as lava tubes, allowing the cross-validation of data and improving
the geologic interpretation.
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and beyond: the ESA PANGAEA-X campaign, this meeting, Geophysical Research Abstract, #EGU2018-4013
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 Rossi, A. P., et al. (2018) Augmented [U+FB01]eld Geology and Geophysics for Planetary Analogues, this
 Unnithan, V., Rossi, A. P. Jaehrig, Tim. (2017) Drone-based photogrammetric survey raw data from ESA
PANGAEA-X 2017 planetary analogue campaign - Data collected on 2017-11-19 [Data set]. Zenodo, DOI: