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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

Authors:
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 (patrizio.torrese@unipv.it), (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 [3] 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
[6], 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 m)
correspond to lava tubes and cavities, intermediate resistivity values (100–800 m) are related to massive and
consolidated materials (mainly lava flows) and the lowest resistivity values (5–50 m) 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.
References:
[1] Garry, W., Bleacher, J. (eds.): Analogs for Planetary Exploration. No. 483 in GSA Special Paper, 567 pp. The
Geological Society of America, Boulder (2011)
[2] Rossi and van Gasselt (2017) Planetary Geology, 441 p. DOI: 10.1007/978-3-319-65179-8
[3] Bessone et al. (2018) Testing technologies and operational concepts for field geology exploration of the Moon
and beyond: the ESA PANGAEA-X campaign, this meeting, Geophysical Research Abstract, #EGU2018-4013
[4] AGPA Team (2018) AGPA web site, http://www.agpa-project.eu, accessed January 2018
[5] Rossi, A. P., et al. (2018) Augmented [U+FB01]eld Geology and Geophysics for Planetary Analogues, this
meeting
[6] 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:
10.5281/zenodo.1084885.
... This first series of collapses do not provide access to relevant sections of the underground tube, being mainly plugged by breakdowns. However, during a recent geophysical campaign using geoelectric tomography, Torrese et al. (2018) demonstrated that intact section of the conduit surely exist in between these collapses. The following sinkhole, Jameo de Prendes, is the first one providing direct access to the pyroduct, situated at approximately 15-20 m below the surface. ...
Chapter
The volcanic island of Lanzarote hosts an impressive variety of cavities formed by different volcanic processes. The presence of well preserved lava fields belonging to historic eruptions and more ancient and weathered quaternary and pliocene terrains and the association with an arid climate provide the unique oportunity of studying volcanic caves at different stages of evolution on the same volcanic island. The different mechanisms of lava tube emplacement can be observed in great detail, from the most recent pyroducts of different sizes formed during the Timanfaya eruption (1730-1736) to the exceptionally voluminous conduits of the Corona volcano, formed during the Last Glacial Maximum and partially submerged by the sea level upraise during the Holocene. In addition, other type of cavities, like explosive and geyser vents, “hornitos” and sinkholes in pyroclastic deposits offer the opportunity to extend the study to other important volcano-speleogenetic processes in different settings. All these cavities are easily accessible and present a variety of morphological, mineralogical, biological and microbiological significances, allowing for a wide range of multidisciplinary studies. The countless analogies with lava tube collapses and other potential volcanic cave features detected on the Moon and Mars also provide an unprecedented research ground that offers hints to solve some open issues in the interpretation of still unresolved planetary cavities. These characteristics make the Lanzarote and Chinijo Islands UNESCO Global an exceptional case where the protection and scientific outreach has been extended to the volcanic subsurface. In this chapter we offer a review of the current knowledge and existing scientific studies on the volcanic caves of Lanzarote and we discuss future researches and protection issues that need to be addressed in order to fully include this geoheritage in strategic plans of environmental protection.
... The integrated use of both surface imaging and subsurface geophysics can be synergistic [5], useful for cross-validation and improved geologic interpretation. The approach can be applied on a planetary analogue target, such as lava tubes, or future planetary cases, such as Lunar or Martian landing sites with the need to characterise, map and explore the subsurface, e.g. through lava tubes, collapses and caves. ...
Testing technologies and operational concepts for field geology exploration of the Moon and beyond: the ESA PANGAEA-X campaign, this meeting
  • Bessone
Bessone et al. (2018) Testing technologies and operational concepts for field geology exploration of the Moon and beyond: the ESA PANGAEA-X campaign, this meeting, Geophysical Research Abstract, #EGU2018-4013
Drone-based photogrammetric survey raw data from ESA PANGAEA-X 2017 planetary analogue campaign -Data
  • V Unnithan
  • A P Rossi
  • Tim Jaehrig
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].
  • Doi Zenodo
Zenodo, DOI: 10.5281/zenodo.1084885.