Deep seismic profiling of the continents and their margins

Tectonophysics 472 (2009) 1–5

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Preface

Deep seismic profiling of the continents and their margins T. Ito a,⁎, T. Iwasaki b, H. Thybo c a b c

Department of Earth Sciences, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522, Japan Earthquake Research Institute, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan Department of Geography and Geology, University of Copenhagen, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark

a r t i c l e

i n f o

Article history: Received 22 January 2009 Accepted 23 January 2009 Available online 19 March 2009

a b s t r a c t Application of deep seismic methods to studies of the crust and lithospheric mantle receives considerable interest and the methods are constantly refined and new methods are developed, which allows the extension of studies to new subjects and regions. Deep seismic methods are applied to a long range of geoscientific subjects in research on the formation and development of crust and lithosphere in continental and oceanic environments. From being an experimental discipline some 30–40 years ago, a series of methods can now be applied almost routinely to research on the lithosphere. However, in many applications, the methods are used up-to their limits at the present technological state. Therefore, development of methods has high priority in the seismic community. This volume provides an overview of recent development of deep seismic techniques and their application to the imaging and probing of the continents and their margins. © 2009 Elsevier B.V. All rights reserved.

1. Introduction Seismic velocity was first determined by use of controlled sources in Ireland about 150 years ago when Mallet (1852) measured the seismic velocity of the granites between two islands in the bay outside Dublin. This technological break-through led to a significant development of methods for observation of waves which have been refracted or reflected at wide-angle incidence in the sedimentary sequences or in the crystalline crust. The theory of seismic reflection and refraction was developed by Knott (1899) and wave propagation by Lamb (1904). The applications of seismic-wave observations for canon locations during World War I, formed the background for the subsequent development of pioneering work on application to seismic prospection. The first patent for seismic refraction prospection was obtained in the twenties by Mintrop as an important method for determination of the location and size of salt domes and, thereby, shallow oil reservoirs. The subsequent development of controlled source reflection seismology was mainly driven by the need for identification of deeper structure. Application to imaging of structure of sedimentary basins was, thereby, developed to a high level by the oil industry from the thirties and onwards. After the first registrations of seismic normal-incidence reflections from the crystalline crust and the Moho by use of chemical explosions as seismic source (Meissner, 1967; Clowes et al., 1968), there was a rapid progress of the deep seismic normal-incidence reflection methods for determination of structure in the Earth's crust. This progress followed ⁎ Corresponding author. E-mail addresses: [email protected] (T. Ito), [email protected] (T. Iwasaki), [email protected] (H. Thybo). 0040-1951/$ – see front matter © 2009 Elsevier B.V. All rights reserved. doi:10.1016/j.tecto.2009.01.018

earlier development of the controlled source methods based on registration of seismic refractions and wide-angle reflections. The International Upper Mantle Project (UMP) of 1961 to 1970 marked a strong increase in the application of controlled source seismological techniques throughout the globe, and led to the first experiments that aimed at imaging the mantle by wide-angle techniques. Two major experiments should be mentioned in this context. The Early Rise experiment took place across most of North America in collaboration between US and Canadian institutions (Warren et al., 1968). Data was acquired at high resolution, at the standards of that time, along 12 profiles radiating out from a common shot point in Lake Superior. Shots were repeatedly fired at the same location during night after day time reinstallation of the seismographs. This major experiment still provides the best available controlled source seismic data from North America but, unfortunately, the profiles are nonreversed and the data is no longer available in digital format. The data has been applied to studies of the lithospheric structure and even of the transition zone (Lewis and Meyer, 1968; Iyer et al., 1969; Masse, 1973; Thybo and Perchuc, 1997; Thybo et al., 2000). Stimulated by these experiments, several seismic expeditions using offshore shots were also undertaken in Japan. The crustal section across Northeast Japan arc, which was characterized by a very low mantle velocity (7.5 km/s), was regarded as a typical structure model of an island arc (e.g. Yoshii and Asano, 1972; Okada et al., 1979). The Deep Probe experiment provided 30 years later a dataset at unprecedented resolution along a ca. 4000 km long profile at the western rim of the Rocky Mountains between central Canada and southern US (Henstock et al., 1998; Kanasewich et al., 2002). The largest controlled source seismological experiment ever carried out is probably the Soviet Peaceful Nuclear Explosion (PNE)

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programme that took place between 1965 and 1988. The data was observed at dense arrays of seismographs to offsets of 4000 km for physically compact sources with high energy output and precise location and onset time. This allows for reliable correlation of seismic phases with a well-defined, short source waveform. The programme included 41 nuclear detonations for geophysical studies (Sultanov et al., 1999). The sources were strong enough for recording of seismic energy on the global seismograph network. The data has been extensively interpreted for lithospheric structure (e.g. Mechie et al., 1993; Nielsen et al., 1999, 2002; Thybo and Perchuc, 1997; Morozova et al., 2000), and for seismic structure at the transition zone (Ryberg et al., 1996; Thybo et al., 2003a). Despite it was generally expected that the energy would be too small at the high frequencies employed, the organizers of the programme decided to even observe the time series for 1100 s after the shooting times, which corresponds to the traveltime from the surface to the centre of the earth and back. Later studies have demonstrated that this decision by the organizers was valuable, as the data allows imaging of the structure at the core mantle boundary (Thybo et al., 2003b; Ross et al., 2004). Also the techniques for normal-incidence imaging of the mantle have been strongly developed over the latest 20 years, such that mantle reflectors down to depths of 240 km have been imaged by use of stacking techniques on multi-channel data sets. The advantage of this type of imaging is the very high resolution of the images, down to less than km scale at 200 km depth. Some examples include observation of reflections from close to the base of the lithosphere (Lie et al., 1990; MONA LISA Working Group, 1997; Steer et al., 1998). Also wide-angle techniques have recently been applied at unprecedented resolution to imaging of the upper mantle structure (Perchuc and Thybo, 1996; Grad et al., 2002). Methods for imaging of the crustal structure developed rapidly during the 70s and 80s with the establishment of several national research groups to apply the new normal-incidence techniques, including e.g. COCORP, BIRPS, DEKORP, ECORS, and LITHOPROBE (e.g. Oliver et al., 1976; Brown et al., 1979; Matthews, 1982; Bois and Damotte, 1983; Clowes, 1984; Bortfeld, 1986; Green et al., 1990; Klemperer and Hobbs, 1992). These programmes soon provided spectacular images of significant structures in the crystalline crust which could be related to, in particular low angle, fault zones (e.g. (Reston et al., 1996; Wernicke, 1981)) and characteristic reflectivity from the lower crust (Klemperer, 1987; Warner, 1990; Levander et al., 1994; Meissner et al., 2006). The Moho either was imaged by a reflection or as the termination of reflectivity from the lower crust, although in some places it may not have been imaged by the normal incidence reflection techniques (Cook et al., 1978; Eaton, 2006). Spectacular dipping reflections at the Moho and in the upper mantle provided images of structure from possible early Proterozoic or Archaean subduction or continental collision (BABEL Working Group, 1989; Calvert et al., 1995; Abramovitz et al., 1997). These findings provided important evidence for the timing of onset of plate tectonics. Also younger structures that may be related to active collision and subduction has been extensively determined (e.g. Warner et al., 1996; Abramovitz and Thybo, 2000; Ruiz et al., 2006;). The seismic reflection profiling in Japan, which started in the 1990s, provided interesting crustal features of island arc including crustal delamination associated with arc–arc collision (e.g. Tsumura et al., 1999; Ito, 2002; Iwasaki et al., 2004) and inland active fault system created by backarc spreading and activated under the subsequent inversion tectonics (Sato et al., 2004). Recent development of the techniques have allowed high resolution imaging of structures at the continental margins which has demonstrated the high variability of types of passive margins (Reston et al., 1996; Mjelde et al., 2008; White et al., 2008), as well as at active margins (ANCORP Working Group 1999; Yuan et al., 2000; Iwasaki et al., 2002; Park et al., 2002; Tsuru et al., 2002, Kodaira et al., 2004, 2007; Sato et al., 2005, Takahashi et al., 2007), and even active zones of continental collision (Pfiffner et al.,

1988; Makovsky et al., 1996; Nelson et al., 1996; Kind et al., 2002; Bruckl et al., 2007). The techniques are still being developed and their range of applicability expands with the availability of modern digital systems and large numbers of seismometers and hydrophones. This development has led to acquisition of data at extremely high resolution, which today allows researchers to obtain images of details of the structures created by dynamics in the Earth, such as fine scale structure of fault zones. 2. Symposium on profiling of the continents and their margins The 12th International Symposium on Deep Seismic Profiling of the Continents and their Margins (Seismix 2006) was held to make status of the development of techniques and to provide an overview of the significant new results that have been produced in recent years by the use of the techniques. The presentations were organized into the following 12 themes. • • • • • • • • • • • • • • •

Active continental margins Intra-continental collision and accretion Continental rifts and basins Passive continental margins Integrated multidisciplinary case studies Continental mantle Numerical modeling of heterogeneity and anisotropy Innovative seismic acquisition and processing techniques Seismic investigations related to mineral resources and volcanoplutonic system Subduction structures of megathrust zones Seismic investigations for disastrous earthquake areas Classic transects Two special sessions were prepared to introduce geophysical and geological features of Japanese islands. Japan session (Keynote talks only) Japan transects (Poster presentation only)

Almost half of the presentations were related to active continental margins including island arcs, which is a much higher fraction than at previous meetings in the same series. This demonstrates the growing interest in studies of “continental margins”, which attains almost similar interest as “continental structure”, such that the series of symposia now truly is on “Deep Seismic profiling of the continents and their margins”. We would like to emphasise the fantastic development of images of the active margins around Japan. These new images, together with the upcoming deep drilling at the margin, have the potential to provide a break-through in our understanding of active margins. The Seismix 2006 symposium was held on September 24 to 29 in 2006 in Hayama, 30 km northeast of the boundary between the Eurasian and Philippine Sea plates. Similar to the previous symposia, all participants were accommodated at the same hotel, the Shonan Village Center, on a hill which has been elevated up to 180 m above the sea level by repeated earthquakes along the plate boundary. The postsymposium field excursion was organized along and around the plate boundary on September 30 to October 2. There was a lively discussion forum both at the symposium and the excursion. About 130 delegates joined the meeting with 59 oral and 118 poster presentations. 3. This volume This volume is based on presentations at the symposium and provides a status of seismic studies on the structure of the continental crust and lithosphere, including development of new techniques. It constitutes a natural continuation of the series of proceedings volumes from previous meetings (Barazangi and Brown, 1986a,b; Matthews and Smith, 1987; Leven et al., 1990; Meissner et al., 1991; Clowes and Green, 1994; White et al., 1996; Klemperer and Mooney,

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1998a,b; Carbonell et al., 2000; Thybo, 2002; Davey and Jones, 2004; Snyder et al., 2006). More than 40% of contributions are associated with studies of active continental margins, which truly reflects the significance of this aspect of the symposium series. These studies have significantly extended the geological and geophysical knowledge on active continental margins. A series of papers presents new results of studies of the structure of arc-trench-back arc and ongoing subduction systems at hitherto unknown detailed imaging. Matsubara et al. (this volume) presents detailed tomographic images of the Philippine Sea Plate subducting beneath southwest Japan in relation to non-volcanic tremors and dehydrated fluids. The structure and seismic activities of the Philippine Sea Plate was also investigated in detail in Kanto area, southernmost part of NE Japan using both active and passive seismic sources by Kimura et al. (this volume). Crustal structure in Chile and the Okhotsk region are presented based on application of a new method for refraction and wide-angle reflection migration. (Pavlenkova et al., this volume). Tsumura et al. (this volume) reveal a possible asperity of the 1703 Genroku earthquake on the upper surface of the subducting Philippine Sea plate beneath the Japanese island arc by interpretation of data from an integrated seismic experiment along the coastal area. Yoon et al. (this volume) presents a highly reflective heterogeneous domain which indicates ascending fluids or partial melts from the Andean subduction zone. Bannister et al. (this volume) reports a lower crustal “bright spot” beneath a young actively rifting basin in the Bay of Plenty. They infer that the “bright spot” is associated with a fragmented sill. Crustal movements in island arcs are another theme which has recently attracted attention. Ikeda et al. (this volume) evaluate the recent slip rate along the active segment of the Itoigawa–Shizuoka Tectonic Line (ISTL) based on images of the subsurface structure as revealed by recent seismic reflection and gravity studies. Using a large set of the accumulated seismic reflection and refraction data, Sato et al. (this volume) present the structural framework of the Kinki triangle at crustal scale, where active faults are densely distributed. Iidaka et al. (this volume) demonstrates the fine structures along and around an active fault, the Atotsugawa fault in central Japan based on a dense refraction/wide-angle reflection survey. The structural evolution of island arcs and continental margins are discussed in several papers based on realistic models. Nakanishi et al. (this volume) demonstrate quantitatively the significant contribution of lower crustal delamination to the formation of continental crust at the Hidaka Collision Zone, Japan. Such model has earlier been suggested from reflection studies. Ito et al. (this volume) provide a first construction of a full crustal cross section of southwest Japan from the trench to the marginal sea, based on data from an integrated seismic experiment. On this basis they discuss the evolution of the Japanese island arc. Li (this volume) presents the rifting process of the Xihu depression at the Paleogene continental margin of the East China Sea. Continental crustal structures on various scales are rigorously studied from new viewpoints. Based on waveform computation using finite-difference method, Flecha (this volume) elucidates fine and heterogeneous structures at lower crustal and Moho levels beneath the SW Iberia. Crustal structure in the Cretaceous Gyeongsang Basin in the easternmost part of the Asian continent is studied by receiver function analysis by Lee et al. (this volume). Goleby et al. (this volume) present a seismic image of a major collision zone between the Tanami region and Aileron Province of the Arunta Orogen in Northern Australia and discuss its importance for the formation of gold deposits. Mielde et al. (this volume) interpret a prominent lower crustal high-velocity layer in the Vøring Basin, NE Atlantic, as eclogite and mafic intrusion based mainly on its velocity. Sandrin et al. (this volume) present a detailed modelling of a layered crust–mantle transition zone between 30 and 35 km depth below the Norwegian– Danish basin, which was formed simultaneously with a large crustal,

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mafic intrusion in the Carboniferous to Permian. Grobys et al. (this volume) reveal the structures of the Campbell Plateau, one of the largest submarine microcontinents in the world, and the Great South Basin in New Zealand by a combination of gravity, magnetic and seismic studies. Several papers present new, innovative methodologies for obtaining insight into crustal structure and its heterogeneity by the use of normal-incidence and wide-angle seismic reflection data. Snyder (this volume) obtains fine P- and S-wave images in southern Abitibi greenstone belt, Canada, indicating the importance of S-wave information not only to physical properties of the crust but to mineral exploration from 3-component high resolution seismic profile. Bleibinhaus et al. (this volume), presenting examples of structural images of upper crust across San Andreas Fault, California and Chesapeake Bay impact structure, Virginia, provide a quantitative discussion on methodology of waveform inversion technique to wideangle data. Kashubin et al. (this volume) provides a velocity model of the crust and upper mantle for the middle Urals derived by application of a modern seismic tomography method to old DSS data collected in the 1970s and 1980's. L'Heureux et al. (this volume) demonstrate how acquisition parameters for mineral explorations can be adjusted in the Archaean Canadian Shield, based on an investigation of heterogeneity and seismic scattering. It provides a strikingly high resolution profile which is also useful for mineral exploration. Yoon et al. (this volume) demonstrate that the Common Reflection Surface (CRS) stack is a powerful method to improve the quality of deep reflection images from low fold data acquisition, based on new reprocessing of old data from the North German Basin. Hobbs et al. (this volume) use a local Monte Carlo strategy to assess velocity–depth models and evaluate their velocity errors. For precise prediction of strong motion in populated areas, Koketsu et al. (this volume) propose a standard procedure to model a basin structure in the Tokyo metropolitan area, Japan, from a data set ranging from geophysical to geological data. This symposium also contributed to the field of arctic geology. From combined reflection (CDP) and refraction/wide-angle reflection studies, Pavlenkova et al. (this volume) elucidate crustal structure beneath the Barents and Kara Seas which has been complicated by fault zones dividing different tectonic blocks. Based on detailed seismic images from seismic profiles and coring expedition, Lebedeva-Ivanova et al. (this volume) discuss the structural correlation among Lomanosov Ridge, Marvin Spur and adjacent basins of the Arctic Ocean. Mints et al. (this volume) reveal the 3-dimensional deep crustal structures of Archaean Karelia craton and Belomorian tectonic province in the Fennoscandian Shield, based on seismic reflection surveys. 4. Thanks to reviewers The editorial process of the present volume has benefited greatly from the involvement by the reviewers of the submitted manuscripts. We would like to acknowledge the fantastic willingness by individuals to evaluate manuscripts, often at short notice. The reviewers have been: Abramovitz, T. (Geological Survey of Denmark and Greenland (GEUS) Andreasen, A. (University of Copenhagen, Department of Geography and Geology) Avendonk, H. (University of Texas, Institute for Geophysics) Bayer, U. (GeoForschungs Zentrum Potsdam) Bannister, S. (Institute of Geological & Nuclear Sciences) Behm, M. (Vienna University of Technology, Institute of Geodesy and Geophysics) Berryman, K. (Institute of Geological & Nuclear Sciences) Bleibinhaus, F. (University of Salzburg, Dept. of Geography and Geology Bogdanova, S. (Lund University, Dept. of Geology) Boldreel, L. (University of Copenhagen, Department of Geography and Geology)

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Brocher, T. (U.S. Geological Survey) Brown, L. (Cornell University, Dept. of Earth and Atmospheric Sciences) Calvert, A. (Simon Fraser University, Dept. of Earth Sciences Carbonell, R. (Instituto de Ciencias de la Tierra, Consejo Superior de Investigaciones Cientificas) Cloetingh, S. (Vrije University, Faculty of Earth and Life Sciences) Clowes, R. (Dept. of Earth and Ocean Sciences, University of British Columbia) Crosson, R. (University of Washington, Dept. of Geophysics Drummond, B. (Geoscience Australia, Earth Monitoring) England, R. (University of Leicester, UK) Fliedner, M. (Dept. of Earth Sciences, University of Cambridge) Fuis, G., (US Geological Survey, Menlo Park) Fujie, G. ((Japan Agency for Earth-Marine Science and Technology) Funck, T. (Geological Survey of Denmark and Greenland, Dept. of Geophysics) Gallart, J. (C.S.I.C., Instituto de Ciencias de la Tierra) Goleby, B. (Geoscience Australia, Minerals Division) Hauser, F. (Dublin Institute for Advanced Studies) Heikkinen, P. (University of Helsinki, Institute of Seismology) Henstock, T. (University of Southampton) Hobbs, R. (Durham University, Earth Sciences) Hole, J. (Virginia Tech, Dept. of Geosciences) Hurich, C. (Dept. of Earth Sciences, Memorial University of Newfoundland) Husebye, E. (Bergen University, Norway) Iidaka, T. (University of Tokyo, Earthquake Research Institute) Jackson, H. (Atlantic Geoscience Center) Jacobsen, B.(Aarhus University, Geophysics Laboratories, Dept of Earth Sciences) Johnson, R. (University of Arizona, Dept. of Geosciences) Juhlin, C. (University of Uppsala, Dept. of Earth Sciences ) Kind, R. (GFZ-Potsdam, Germany) Knapp, C. (University of South Carolina, Dept. of Geological Sciences Kodaira, S. (Japan Agency for Earth-Marine Science and Technology, Institute for Research on Earth Evolution) Kopp, H. (IFM-GEOMAR) Korja, A. (University of Helsinki, Institute of Seismology) Krawczyk, C. (Leibniz Institute for Applied Geosciences, Seismic, Magnetics and Gravimetry Larry, B. (Dept. of Earth and Atmospheric Sciences, Cornell University) Laigle-Marchand, M. (Institut de Physique du Globe de Paris, France) Levander, A. (Rice University, Dept. of Geology and Geophysics) Levin, V. (Rutgers University, Dept. of Geology and Geophysics) Louie, J. (University of Reno, Nevada, USA) McBride, J. (Brigham Young University, Dept. of Geology) Meissner, R. (Christian Albrechts University, Institute of Geosciences) Milkereit, B. (University of Toronto, Dept. of Physics) Miller, K. (Dept. of Geological Sciences, University of Texas at El Paso) Mjelde, R. (University of Bergen, Dept. of Earth Science) Nielsen, L. (University of Copenhagen, Geological Institute) Nielsen, S. (Aarhus University, Geophysics Laboratories, Dept. of Earth Sciences) Parsons, T. (U.S. Geological Survey) Pratt, T. (University of Washington, College of Ocean & Fishery Science) Rabbel, W. (University of Kiel, Institute of Geophysics) Stephenson, R. (Vreie Universiteit Amsterdam, The Netherlands) Romanowicz, B. (Seismological Laboratory, University of California at Berkeley) Scheck-Wenderoth, M. (GeoForschungsZentrum Potsdam) Scherwath, M. (IFM-GEOMAR, Leibniz-Institute of Marine Sciences)

Shinohara, M. (University of Tokyo, Earthquake Research Institute) Snyder, D. (Geological Survey of Canada) Sroda, P. (Polish Academy of Sciences, Institute of Geophysics) Tryggvason, A. (University of Uppsala, Dept. of Geophysics) Tsumura, N. (Dept. of Earth Sciences, Chiba University) Acknowledgments The 12th International Symposium on Deep Seismic Profiling of the Continents and their Margins (Seismix 2006) was organized in collaboration between the Earthquake Research Institute (ERI) of the University of Tokyo, Japan Agency for the Marine-Earth Science and Technology (JAMSTEC), National Institute for Earth Science and Disaster Prevention (NIED), with Profs. T. Iwasaki and H. Sato of ERI as Chairperson and Secretary General of the Organizing Committee, respectively. The Organizing Committee acknowledges with gratitude the financial support from different funding agencies without which this symposium would not have been possible. Funding was provided Ministry of Education, Culture, Sports, Science and Technology (MEXT), Japan Society for the Promotion of Science (JSPS), Graduate School for Advanced Studies, Yokosuka City, InterMARGINS, Tokio Marine Kagami Memorial Foundation, Japan Petroleum Exploration Co. Ltd., Teikoku Oil Co. Ltd., JGI, Inc., Kawasaki Geological Engineering Co. Ltd., Japan Continental Shelf Survey Co. Ltd., Hanshin Geological Engineering Co. Ltd., Obayashi Corporation, Technical Research Institute, and Hakusan Corporation. The Committee greatly appreciates the sponsorship of the scientific program by International Association of Seismology and Physics of the Earth's Interior (IASPEI), International Lithosphere Program (ILP), Japanese Geoscience Union, Seismological Society of Japan, and Geological Society of Japan. The Committee is grateful to Ms. Y. Izaki and S. Ogino of ERI, Mr. S. Hanzawa of Shonan Village Inc., and Prof. D. Okaya of University of Southern California for preparing Seismix 2006 and all session chairs. The Guest editors of this volume are very thankful to Mr. N. Komada of Chiba University for his support to the editorial works. References Abramovitz, T., Thybo, H., 2000. Seismic images of Caledonian, lithosphere-scale collision structures in the southeastern North Sea along Mona Lisa Profile 2. Tectonophysics 317, 27–54. Abramovitz, T., Berthelsen, A., Thybo, H., 1997. Proterozoic sutures and terranes in the southeastern Baltic Shield interpreted from BABEL deep seismic data. Tectonophysics 270, 259–277. ANCORP Working Group, 1999. Seismic reflection image revealing offset of Andean subduction zone earthquake locations into oceanics mantle. Nature 397, 341–344. BABEL Working Group, 1989. Seismic reflection evidence for the location of the Iapetus suture west of Ireland. J. Geol. Soc. London 146, 409–412. Barazangi, M., Brown, L. (Eds.), 1986a. Reflection Seismology: A Global Perspective. Am. Geophys. Union. Geodyn. Ser., vol. 13. 311 pp. Barazangi, M., Brown, L. (Eds.), 1986b. Reflection Seismology: The Continental Crust. Am. Geophys. Union, Geodyn. Ser., vol. 14. 339 pp. Bois, C., Damotte, B., 1983. Exploration of the Earth's crust – The Ecors Program. Recherche 14, 850–853. Bortfeld, R.K., 1986. The German deep-reflection project Dekorp. Geophysics 51 (2), 517–518. Brown, L., Brewer, J., Cook, F., Kaufman, S., Long, G., Oliver, J., 1979. COCORP deep seismicreflection studies of continental lithosphere – regional variations in intra basement structure. Geophysics 44, 383–384. Bruckl, E., Bleibinhaus, F., Gosar, A., Grad, M., Guterch, A., Hrubcova, P., Keller, G.R., Majdanski, M., Sumanovac, F., Tiira, T., Yliniemi, J., Hegedus, E., Thybo, H., 2007. Crustal structure due to collisional and escape tectonics in the Eastern Alps region based on profiles Alp01 and Alp02 from the ALP 2002 seismic experiment. J. Geophys. Res. -Solid Earth 112 (B6). doi:10.1029/2006JB004687. Calvert, A.J., Sawyer, E.W., Davis, W.J., Ludden, J.N., 1995. Archean subduction inferred from seismic images of a mantle suture in the Superior Province. Nature 375, 670–674. Carbonell, R., Gallart, J., Torne, M., 2000. Deep seismic profiling of the continents and their margins. Tectonophysics 329, VII–VIII. Clowes, R.M., 1984. Phase-1 lithoprobe – a coordinated National Geoscience Project. Geosci. Canada 11, 122–126. Clowes, R.M., Green, A.G. (Eds.), 1994. Seismic Reflection Probing of the Continents and their Margins. Tectonophysics, vol. 232. 450 pp.

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