Abstract
The structure of Cerdanya Basin (north-east of Iberian Peninsula) is partly known from geological cross sections, geological maps and vintage geophysical data. However, these data do not have the necessary resolution to characterize some parts of Cerdanya Basin such as the thickness of soft soil, geometry of bedrock or geometry of geological units and associated faults. For all these reasons, the main objective of this work is to improve this deficiency carrying out a detailed study in this Neogene basin applying jointly the combination of passive seismic methods (H/V spectral ratio and seismic array) and electromagnetic methods (audio-magnetotelluric and magnetotelluric method). The passive seismic techniques provide valuable information of geometry of basement along the profile. The maximum depth is located near Alp village with a bedrock depth of 500 m. The bedrock is located in surface at both sites of profile. The Neogene sediments present a shear-wave velocity between 400 and 1000 m/s, and the bedrock basement presents a shear-wave velocity values between 1700 and 2200 m/s. These results are used as a priori information to create a 2D resistivity initial model which constraints the inversion process of electromagnetic data. We have obtained a 2D resistivity model which is characterized by (1) a heterogeneous conductivity zone (<40 Ohm m) that corresponds to shallow part of the model up to 500 m depth in the centre of the profile. These values have been associated with Quaternary and Neogene sediments formed by silts, clays, conglomerates, sandstones and gravels, and (2) a deeper resistive zone (1000–3000 Ohm m) interpreted as Palaeozoic basement (sandstones, limestones and slates at NW and conglomerates and microconglomerates at SE). The resistive zone is truncated by a discontinuity at the south-east of the profile which is interpreted as the Alp-La Tet Fault. This discontinuity is represented by a more conductive zone (600 Ohm m approx.) and is explained as a combination of fractured rock and a fluid network. The result highlights that the support between different geophysical methods is essential in producing geophysical meaningful models.
Similar content being viewed by others
References
Aki K (1957) Space and time spectra of stationary stochastic waves, with special reference to microtremors. Bull Earth Res Inst 35:415–456
Arango C, Marcuello A, Ledo J, Queralt P (2009) 3D magnetotelluric characterization of the geothermal anomaly in the Llucmajor aquifer system (Majorca, Spain). J Appl Geophys 68(4):479. doi:10.1016/j.jappgeo.2008.05.006
Asten MW, Henstridge JD (1984) Array estimators and use of microseisms for reconnaissance of sedimentary basin. Geophysics 49:1828–1837
Bard P-Y (1999) Microtremor measurements: a tool for site effect estimation? State-of-the art paper. In: Irikura K, Kudo K, Okada H, Sasatani T (eds) Second international symposium on the effects of surface geology on seismic motion, Yokohama, December 1–3, 1998, Balkema 1999, vol 3, pp 1251–1279
Bard PY, SESAME-Team (2004) Guidelines for the implementation of the H/V spectral ratio technique on ambient vibrations-measurements, processing and interpretations, SESAME European research project EVG1-CT-2000-00026, deliverable D23.12. http://sesame-fp5.obs.ujf-grenoble.fr
Beamish D, Travassos JM (1992) The use of the D+ solution in magnetotelluric interpretation. J Appl Geophys 29:1–19
Benjumea B, Macau A, Gabàs A, Bellmunt F, Figueras S, Cirés J (2011) Integrated geophysical profiles and H/V microtremor measurements for subsoil characterization. Near Surface Geophys 9(5):413–425
Bonnefoy-Claudet S (2004) Nature du bruit de fond sismique: Implications pour les études des effects de site, PhD. Thesis, Joseph Fourier University (Grenioble-France)
Cabrera LI, Roca E, Santanach P (1988) Basin formation at the end of a strike-slip fault: the Cerdanya Basin (Eastern Pyrenees). J Geol Soc Lond 145:261–268
Chave AD, Jones AG (2012) The magnetotelluric method. Cambridge University Press, Cambridge. doi:10.1017/CBO9781139020138
Colombo D, Heho T, Mc Neice GS (2012) Integrated seismic-electromagnetic workflow for sub-basalt exploration in northwest Saudi Arabia. The Leading Edge 31:42; doi:10.1190/1.3679327
Delgado J, López Casado C, Estévez A, Giner J, Cuenca A, Molina S (2000) Mapping soft soils in the Segura river valley (SE Spain): a case study of microtremors as an exploration tool. J Appl Geophys 45:19–32
Fäh D, Kinf F, Giardini D (2001) A theoretical investigation of average H/V ratios. Geophys J Int 145:535–549. doi:10.1046/j.1365-246X.2001.01406.x
Falgàs E, Ledo J, Benjumea B, Queralt P, Marcuello A, Teixidó T, Martí A (2011) Integrating hydrogeological and geophysical methods for the characterization of a deltaic aquifer system. Surv Geophys. doi:10.1007/s10712-011-9126-2
Gabàs A, Marcuello A (2003) The relative influence of different types of magnetotelluric data on joint inversions. Earth Planets Space 55(5):243–248
Gabàs A, Macau A, Benjumea B, Bellmunt F, Figueras S, Vilà M (2014) Combination of geophysical methods to support urban geological mapping. Surv Geophys 35(4):983–1002. doi:10.1007/s10712-013-9248-9
Gallardo LA, Meju MA (2003) Characterization of heterogeneous near-surface materials by joint 2D inversion of dc resistivity and seismic data. Geophys Res Lett 30(13):1658. doi:10.1029/2003GL017370
Gallardo LA, Meju MA (2004) Joint two-dimensional DC resistivity and seismic travel time inversion with cross-gradient constraints. J Geophys Res 109. doi:10.1029/2033JB002716
Gallardo LA, Meju MA (2007) Joint two-dimensional cross-gradient imaging for magnetotelluric and seismic travel time data for structural and lithological classification. Geophys J Int 169:1261–1272. doi:10.111/j.1365-246X.2007.03366.x
García X, Ledo J, Queralt P (1999) 2-D Inversion of 3-D magnetotelluric data: the Kayabe dataset. Earth Planets Space 51:1135–1143
Grandjean G, Gourry JC, Sanchez O, Bitri A, Garambois S (2011) Structural study of the Ballandaz landslide (French Alps) using geophysical imagery. J Appl Geophys 75:531–542. doi:10.1016/j.jappgeo.2011.07.008
Gunther T, Rücker C (2006) A new joint inversion approach applied to the combined tomography of DC Resistivity and Seismic refraction data. In: 19th EEGS symposium on the application of geophysics to engineering and environmental problems
Ibs-von Seht M, Wohlenberg J (1999) Microtremor measurements used to map thickness of soft sediments. Bull Seismol Soc Am 89(1):250–259
Kim JH, Yi MJ, Hwang SH, Song Y, Cho SJ, Synn J-H (2007) Integrated geophysical surveys for the safety evaluation of a ground subsidence zone in a small city. J Geophys Eng 4:332–347. doi:10.1088/1742-2132/4/3/S12
Konno K, Ohmachi T (1998) Ground motion characteristics estimated from spectral ratio between horizontal and vertical components of microtremor. Bull Seismol Soc Am 88:228–241
Kwon HS, Song Y, Yi MJ, Chung HJ, Kim KS (2006) Case histories of electrical resistivity and controlled-source magnetotelluric surveys for the site investigation of tunnel construction. J Environ Eng Geophys 11:237–248
Lachet C, Bard PY (1994) Numerical and theoretical investigations on the possibilities and limitations of the Nakamura’s technique. J Phys Earth 42:377–397
Ledo J, Jones A (2002) Electromagnetic images of a strike-slip fault: The Tintina fault—Northern Canadian. Geophys Res Lett 29. doi:10.1029/2001GL013408
Ledo J, Jones AG, Siniscalchi A, Campanyà J, Kiyan D, Romano G, Rouai M, opoMed MT Team (2011) Electrical signature of modern and ancient tectonic process in the crust of the Atlas mountains of Morocco. Phys Earth Planet Interiors 185:82–88
Lee W, Stewart S (1981) Principles and applications of microearthquake networks. Academic Press, London
Macau A (2008) Microzonación sísmica. Contribución a los estudios de peligrosidad sísmica a escala local en zonas rurales y urbanas. PhD thesis
McNeice GW, Jones AG (2001) Multisite, multifrequency tensor decomposition of magnetotelluric data. Geophysics 66(1):158–173
Meqbel N, Ritter O, DESIRE Group (2013) A magnetotelluric transect across the Dead Sea Basin: electrical properties of geological and hydrological units of the upper crust. Geophys J Int 193(3):1415—1431. doi:10.1093/gji/ggt051
Motsuno T, Seama N, Evans RL, Chave AD, Baba K, Goto T, Heinson G, Boren G, Yoneda A, Utada H (2010). Upper mantle electrical resistivity structure beneath the central Mariana subduction system. Geochem Geophys Geosyst 11(9). doi:10.1029/2010GC003101
Muñoz G (2014) Exploring for geothermal resources with electromagnetic methods. Surv Geophys 35(1):101–122
Nakamura Y (1989) A method for dynamic characteristics estimations of subsurface using microtremors on the ground surface. QR RTRI 30:25–33
Nogoshi M, Igarashi T (1971) On the amplitude characteristics of microtremor (Part 2). J Seism Soc Jpn 24:26–40 (in Japanese with English abstract)
Ogawa Y, Takakura S, Honkura Y (2002) Resistivity structure across Itoigawa-Shizuoka tectonic line and its implications for concentrated deformation. Earth Planet Space 54:1115–1120
Ogaya X, Ledo J, Queralt P, Marcuello A, Quintà A (2013) First geoelectrical image of the subsurface of the Hontomín site (Spain) for CO2 geological storage: a magnetotelluric 2D characterization. Int J Greenhouse Gas Control 13:168–179
Ortuño M, Queralt P, Martí A, Ledo J, Masana E, Perea H, Santanach P (2008) The North Maladeta Fault (Spanich Central Pyrenees) as te Vielha 1923 earthquake seismic source: recent activity revealed by geomorphological and geophysical research. Tectonophysics 453:246–262
Parolai S, Bormann P, Milkereit C (2002) New relationship between VS, thickness of sediments, and resonance frequency calculated by the H/V ratio of seismic noise for the Cologne Area (Germany). Bull Seismol Soc Am 92(6):2521–2527
Patro BPK, Harinarayana T, Sastry RS, Rao M, Manoj C, Naganjaneyulu K, Sarma SVS (2005) Electrical Imaging of Narmada-Son Lineament Zone, central India form magnetotellurics. Phys Earth Planet Inter 148:215–232
Piña-Varas P, Ledo J, Queralt P, Roca E, García-Lobón J, Ibarra P, Biete C (2013) Two-dimensional magnetotelluric characterization of the El Hito Anticline (Loranca Basin, Spain). J Appl Geophys 95:121–134
Pous J, Julia R, Solé Sugranes L (1986) Cerdanya basin geometry and its implication on the neogene evolution of the Eastern Pyrenees. Tectonophysics 129:355–365
Queralt P, Jones AG, Ledo J (2007) Electromagnetic imaging of a complex ore body: 3D forward modeling, sensitivity tests, and down-mine measurements. Geophysics 72. doi:10.1190/1.2437105
Rivero LI (1993) Estudio Gravimétrico del Pirineo Oriental. PhD thesis. Universitat de Barcelona, pp 103–117
Roca E (1996) E10 The Neogene Cerdanya and Seu d’Urgell intramontane basins (Eastern Pyrenees). In: Friend PF, Dabrio CJ (eds) Tertiary basins of Spain: the stratigraphic record of crustal kinematics. Cambridge University Press, Cambridge, pp 114–119
Rodi W, Mackie R (2001) Nonlinear conjugate gradients algorithm for 2-D magnetotelluric inversion. Geophysics 66:174–187
Rubinat M, Ledo J, Roca E, Rosell O, Queralt P (2010) Magnetotelluric characterization of a salt diapir: a case study on Bicorb-Quesa Diapir (Prebetic Zone, SE Spain). J Geol Soc Lond 167:145–153
Unsworth MJ, Malin PE, Egbert GD, Booker JR (1997) Internal structure of the San Andreas fault at Parkfield, California. Geology 25:359–362
Wathelet M (2003) Report on the inversion of velocity profile and version 0 of the inversion software. SESAME Report D14:07
Wathelet M, Jongmans D, Ohrnberger M (2004) Surface wave inversion using a direct search algorithm and its application to ambient vibration measurements, EGU, first general assembly. Nice, France
Wathelet M, Jongmans D, Ohrnberger M, Bonnefoy-Claudet S (2008) Array performances for ambient vibrations on a shallow structure and consequences over Vs inversion. J Seismol 12:1–19
Yamaguchi S, Sutoh S, Hashimoto H, Murakami H and Takagi N (2002) 2-D resistivity structure of the southern part of the Nojima fault and relationship to the activity of the faults. Zisin (J Seismol Soc Jpn) 55:143–151
Yamaguchi S, Ogawa Y, Fuji-ta K, Ujihara N, Inokushi H, Oshiman N (2010) Audio-frequency magnetotelluric imaging of the Hijima fault, Yamasaki fault system, southwest Japan. Earth Planet Space 62:401–411
Acknowledgments
This work was supported by the Spanish Ministry of Science and Innovation project “Progress In Electromagnetic Research for CO2 geological reservoirs (PIER-CO2)”. We thank Prof. M. J. Rycroft, Dr. Muñoz and Dr. Ferguson for their interesting comments and suggestions on our manuscript.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Gabàs, A., Macau, A., Benjumea, B. et al. Joint Audio-Magnetotelluric and Passive Seismic Imaging of the Cerdanya Basin. Surv Geophys 37, 897–921 (2016). https://doi.org/10.1007/s10712-016-9372-4
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10712-016-9372-4