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1. The seismicity of Mars

Author

Simon Stähler, Anna Horleston, Sharon Kedar, John-Robert Scholz, L. Luno, J. B. McClean, Henri Samuel, Fabian Euchner, S. Barkaoui, Tristram Warren, Mélanie Drilleau, Martin Schimmel, Maren Böse, M. Nonon, M. van Driel, Nicholas A Teanby, Alexander E. Stott, Savas Ceylan, Ludovic Margerin, A. Jacob, Brigitte Knapmeyer-Endrun, William B. Banerdt, Guenole Mainsant, Tamara Gudkova, Antoine Lucas, T. Gabsi, Renee Weber, Taichi Kawamura, Vincent Conejero, Eléonore Stutzmann, Daniele Antonangeli, C. Agard, Constantinos Charalambous, C. Ferrier, P. Combes, K. Hurst, Philippe Lognonné, Don Banfield, Aymeric Spiga, William T. Pike, Constanza Pardo, J. A Rodriguez Manfredi, Martin Knapmeyer, Attilio Rivoldini, Francis Nimmo, U. R. Christensen, Sue Smrekar, Ingrid Daubar, R. Llorca-Cejudo, Mark P. Panning, Scott D. King, Eric Beucler, Foivos Karakostas, Amir Khan, E. Barrett, Mark A. Wieczorek, Raphaël F. Garcia, Clément Perrin, Naomi Murdoch, David Mimoun, C. Yana, John Clinton, Domenico Giardini, Swiss National Supercomputing Centre, Swiss National Science Foundation, Agence Nationale de la Recherche (France), State Secretariat for Education, Research and Innovation (Switzerland), UK Space Agency, California Institute of Technology, German Centre for Air and Space Travel, Schimmel, Martin, Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Institute of Geophysics [ETH Zürich], Department of Earth Sciences [Swiss Federal Institute of Technology - ETH Zürich] (D-ERDW), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Institut de Physique du Globe de Paris, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Department of Mechanical Engineering [Imperial College London], Imperial College London, Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, INSTITUT OF GEOPHYSICS ETHZ, Swiss Seismological Service, Department of Earth and Environmental Sciences [München], Ludwig-Maximilians-Universität München (LMU), Department of Geological Sciences [Gainesville] (UF|Geological), University of Florida [Gainesville] (UF), Cornell University [New York], Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), European Academy-EURAC, Institute for Applied Remote Sensing, Kyoto University [Kyoto], Departments of Anesthesiology and Physiology and Biophysics, University of Alabama at Birmingham [ Birmingham] (UAB), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-École des Ponts ParisTech (ENPC)-École polytechnique (X)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), unité de recherche de l'institut du thorax UMR1087 UMR6291 (ITX), Université de Nantes - UFR de Médecine et des Techniques Médicales (UFR MEDECINE), Université de Nantes (UN)-Université de Nantes (UN)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), De la Préhistoire à l'Actuel : Culture, Environnement et Anthropologie (PACEA), Université de Bordeaux (UB)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Schmidt United Institute of Physics of the Earth [Moscow] (IPE), Russian Academy of Sciences [Moscow] (RAS), NASA, Deutsches Zentrum für Luft- und Raumfahrt (DLR), Centre National d'Études Spatiales [Toulouse] (CNES), Laboratoire d'Ingénierie des Matériaux (LIM), Institut de recherche en astrophysique et planétologie (IRAP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), UNS-CNRS-Observatoire de la Côte d'Azur, Department of Earth and Planetary Sciences [Santa Cruz], University of California [Santa Cruz] (UCSC), University of California-University of California, School of Earth Sciences [Bristol], University of Bristol [Bristol], Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut Supérieur de l'Aéronautique et de l'Espace - ISAE-SUPAERO (FRANCE), Department of Earth Sciences [ETH Zürich] (D-ERDW), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich)-Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich), California Institute of Technology (CALTECH)-NASA, Department of Geological Sciences, University of Florida [Gainesville], Oncogenesis Stress Signaling (OSS), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-CRLCC Eugène Marquis (CRLCC), Cornell University, Université d'Angers (UA)-Université de Nantes - Faculté des Sciences et des Techniques, Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Nantes - UFR de Médecine et des Techniques Médicales (UFR MEDECINE), Université de Nantes (UN)-Université de Nantes (UN), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Université Fédérale Toulouse Midi-Pyrénées-Centre National d'Études Spatiales [Toulouse] (CNES)-Météo France-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS), Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015 - 2019) (COMUE UCA), Schimmel, Martin [0000-0003-2601-4462], Department of Earth and Environmental Sciences [Munich], Laboratoire de Planétologie et Géodynamique UMR6112 (LPG), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Nantes - Faculté des Sciences et des Techniques, Université de Nantes (UN)-Université de Nantes (UN)-Université d'Angers (UA), Laboratoire de Géophysique Interne et Tectonophysique (LGIT), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Laboratoire Central des Ponts et Chaussées (LCPC)-Institut des Sciences de la Terre (ISTerre), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut national des sciences de l'Univers (INSU - CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)-PRES Université de Grenoble-Institut de recherche pour le développement [IRD] : UR219-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR), École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPG Paris), Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Unité de recherche de l'institut du thorax (ITX-lab), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), University of California [Santa Cruz] (UC Santa Cruz), University of California (UC)-University of California (UC), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), and ANR-14-CE36-0012,SEISMARS,Seismology on Mars(2014)

Subjects
Seismometer, 010504 meteorology & atmospheric sciences, [PHYS.ASTR.EP]Physics [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], Mars, Induced seismicity, InSight Mars Marsbeben Seismizität, 010502 geochemistry & geophysics, seismology, 01 natural sciences, Mantle (geology), Elysium, [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, Autre, Planet, inner planets, ComputingMilieux_MISCELLANEOUS, Seismology, InSight, 0105 earth and related environmental sciences, Seismicity, Crust, Geology, Mars Exploration Program, [SDU]Sciences of the Universe [physics], 13. Climate action, General Earth and Planetary Sciences
Abstract

The InSight (Interior Exploration using Seismic Investigations, Geodesy and Heat Transport) mission landed in Elysium Planitia on Mars on 26 November 2018 and fully deployed its seismometer by the end of February 2019. The mission aims to detect, characterize and locate seismic activity on Mars, and to further constrain the internal structure, composition and dynamics of the planet. Here, we present seismometer data recorded until 30 September 2019, which reveal that Mars is seismically active. We identify 174 marsquakes, comprising two distinct populations: 150 small-magnitude, high-frequency events with waves propagating at crustal depths and 24 low-frequency, subcrustal events of magnitude Mw 3–4 with waves propagating at various depths in the mantle. These marsquakes have spectral characteristics similar to the seismicity observed on the Earth and Moon. We determine that two of the largest detected marsquakes were located near the Cerberus Fossae fracture system. From the recorded seismicity, we constrain attenuation in the crust and mantle, and find indications of a potential low-S-wave-velocity layer in the upper mantle. © 2020, The Author(s), under exclusive licence to Springer Nature Limited., We acknowledge NASA, CNES and its partner agencies and institutions (UKSA, SSO, DLR, JPL, IPGP-CNRS, ETHZ, IC and MPS-MPG) and the flight operations team at JPL, SISMOC, MSDS, IRIS-DMC and PDS for providing SEIS data. The Swiss co-authors were jointly funded by (1) the Swiss National Science Foundation and French Agence Nationale de la Recherche (SNF-ANR project 157133 ‘Seismology on Mars’), (2) the Swiss National Science Foundation (SNF project 172508 ‘Mapping the internal structure of Mars’), (3) the Swiss State Secretariat for Education, Research and Innovation (SEFRI project ‘MarsQuake Service-Preparatory Phase’) and (4) ETH Research grant no. ETH-06 17-02. Additional support came from the Swiss National Supercomputing Centre (CSCS) under project ID s922. The Swiss contribution in the implementation of the SEIS electronics was made possible by funding from the federal Swiss Space Office (SSO) and contractual and technical support from the ESA-PRODEX office. The French Team acknowledge the French Space Agency CNES, which has supported and funded all SEIS-related contracts and CNES employees, as well as CNRS and the French team universities for personal and infrastructure support. Additional support was provided by ANR (ANR-14-CE36-0012-02 and ANR-19-CE31-0008-08) and, for the IPGP team, by the UnivEarthS Labex programme (ANR-10-LABX-0023), IDEX Sorbonne Paris Cité (ANR-11-IDEX-0005-0). SEIS-SP development and delivery were funded by the UK Space Agency. A portion of the work was carried out at the InSight Project at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration. The MPS SEIS team acknowledges funding for development of the SEIS leveling system by the DLR German Space Agency. We thank gempa GmbH for software development related to the MQS tools. This paper is InSight contribution number 102.

Published
2020
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2. SEIS: Insight’s Seismic Experiment for Internal Structure of Mars

Author

L. Perrin, C. Bonjour, N. Toulemont, Jean-Luc Berenguer, G. Perez, James Wookey, A. G. Mukherjee, Hallie Gengl, Edward A. Miller, Delphine Faye, Antoine Mocquet, J. Sicre, B. Vella, D. Dilhan, C. Larigauderie, John C. Bousman, M. Nonon, Y. Bennour, Véronique Dehant, Jeffrey W. Umland, T. Nebut, D. Hernandez, M. Eberhardt, Vincent Conejero, Rudolf Widmer-Schnidrig, Philippe Lognonné, G. de los Santos, S. A. D’Agostino, Savas Ceylan, Justin N. Maki, G. Aveni, P. Revuz, S. de Raucourt, C. Aicardi, Clément Perrin, A. K. Delahunty, Constanza Pardo, Domenico Giardini, L. Pou, Robert J. Calvet, D. Savoie, O. Robert, V. Gharakanian, S. Ben Charef, Constantinos Charalambous, Kerry Klein, S. M. Madzunkov, J. M. Desmarres, Sue Smrekar, S. B. Calcutt, F. Grinblat, Nicholas A Teanby, I. M. Standley, Naomi Murdoch, Brigitte Knapmeyer-Endrun, M. Deleuze, C. Doucet, William T. Pike, Tom L. Hoffman, F. Mialhe, Cecily M. Sunday, J. Paredes-Garcia, Matthew P. Golombek, P. Bhandari, Huafeng Liu, B. Pouilloux, E. Blanco, Gabriel Pont, Simon Stähler, M. E. Johnson, Nicolas Verdier, L. Luno, Ned W. Ferraro, R. Perez, Mélanie Drilleau, F. Ijpelaan, B. Lecomte, M. van Driel, A. Sauron, I. Estève, Mark P. Panning, David Mimoun, P. A. Dandonneau, B. Kenda, T. Gabsi, W. Raff, P. Boutte, T. Warren, Joan Ervin, Fabian Euchner, S. Tillier, K. J. Hurst, Stephen Larson, Davor Mance, Mark A. Wieczorek, J. A. Rodriguez-Manfredi, Justin Lin, Jaime Singer, M. Monecke, Robert W. Denise, E.-P. Miettinen, Maren Böse, E. Locatelli, I. Savin de Larclause, J. Gagnepain-Beyneix, L. Khachikyan, Philippe Laudet, T. Carlier, Alexander E. Stott, Neil Bowles, Brian Bone, C. Imbert, Sharon Kedar, A. Rosak, Fred Calef, O. Pot, O. M. Avalos, P. Labrot, Jeroen Tromp, Lucile Fayon, C. Moreau, J. Baroukh, William B. Banerdt, M. Bierwirth, Ranah Irshad, M. André, Christopher T. Russell, S. L. Marshall, M. Parise, J.-R. Meyer, P. Pasquier, N. Faye-Refalo, Ingrid Daubar, M. A. Balzer, R. Gonzalez, M. Hetzel, K. Brethomé, Y. Pahn, Raphaël F. Garcia, J. tenPierick, U. R. Christensen, Farah Alibay, Renee Weber, Robert G. Deen, Eléonore Stutzmann, J. Temple, Don Banfield, A. Bouisset, D. B. Klein, A. Borrien, Ashitey Trebi-Ollennu, R. Llorca-Cejudo, L. J. Facto, J. M. Mouret, Alexis Paillet, Peter Zweifel, P. Bruneau, Catherine L. Johnson, C. Brysbaert, J. E. Feldman, A. Kramer, Luigi Ferraioli, Jane Hurley, Taichi Kawamura, Nicholas Onufer, W. Kühne, Eric Beucler, Amir Khan, M. Sodki, L. Kerjean, A. Sylvestre-Baron, C. Desfoux, C. Yana, John Clinton, J. R. Willis, Juan Villalvazo, Pierre Delage, Mihail P. Petkov, M. C. Wallace, T. Camus, Ioannis G. Mikellides, Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS), Institute of Geophysics [ETH Zürich], Department of Earth Sciences [Swiss Federal Institute of Technology - ETH Zürich] (D-ERDW), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich)- Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Department of Mechanical Engineering [Imperial College London], Imperial College London, Max-Planck-Institut für Sonnensystemforschung = Max Planck Institute for Solar System Research (MPS), Max-Planck-Gesellschaft, Centre National d'Études Spatiales [Toulouse] (CNES), Geological Institute (ETHZ), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), University of Oxford, Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), NASA Marshall Space Flight Center (MSFC), Institut de recherche en astrophysique et planétologie (IRAP), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Institut d'astrophysique spatiale (IAS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National d’Études Spatiales [Paris] (CNES), Laboratoire de Mecanique des Fluides et d'Acoustique (LMFA), École Centrale de Lyon (ECL), Université de Lyon-Université de Lyon-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Institut National des Sciences Appliquées de Lyon (INSA Lyon), Université de Lyon-Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS), Department of Atmospheric, Oceanic and Planetary Physics [Oxford] (AOPP), Advanced Technology and Research, Space Science and Technology Department [Didcot] (RAL Space), STFC Rutherford Appleton Laboratory (RAL), Science and Technology Facilities Council (STFC)-Science and Technology Facilities Council (STFC), Clarendon Laboratory [Oxford], Huazhong University of Science and Technology [Wuhan] (HUST), Kinemetrics, Cornell University [New York], Centro de Astrobiologia [Madrid] (CAB), Instituto Nacional de Técnica Aeroespacial (INTA)-Consejo Superior de Investigaciones Científicas [Madrid] (CSIC), University of California [Los Angeles] (UCLA), University of California (UC), Institut of GeophysicsETHZ, Géoazur (GEOAZUR 7329), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Swiss Seismological Service, Royal Observatory of Belgium [Brussels] (ROB), Géotechnique (cermes), Laboratoire Navier (navier umr 8205), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS), Institut de minéralogie, de physique des matériaux et de cosmochimie (IMPMC), Muséum national d'Histoire naturelle (MNHN)-Institut de recherche pour le développement [IRD] : UR206-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), University of British Columbia (UBC), Planetary Science Institute [Tucson] (PSI), Laboratoire national de métrologie et d'essais - Systèmes de Référence Temps-Espace (LNE - SYRTE), Systèmes de Référence Temps Espace (SYRTE), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), University of Bristol [Bristol], Department of Geosciences [Princeton], Princeton University, Joseph Louis LAGRANGE (LAGRANGE), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Universität Stuttgart [Stuttgart], School of Earth Sciences [Bristol], Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Max-Planck-Institut für Sonnensystemforschung (MPS), University of Oxford [Oxford], Max Planck Institute for Solar System Research (MPS), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université Paris Diderot - Paris 7 (UPD7)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), University of California, INSTITUT OF GEOPHYSICS ETHZ, Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Karlsruhe Institute of Technology and Stuttgart University, Institut Supérieur de l'Aéronautique et de l'Espace - ISAE-SUPAERO (FRANCE), California Institute of Technology (CALTECH)-NASA, Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud]), Université Nice Sophia Antipolis (... - 2019) (UNS), Université Côte d'Azur (UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS), Département Electronique, Optronique et Signal (DEOS), Department of Earth Sciences [ETH Zürich] (D-ERDW), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich)-Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich), Laboratoire de Planétologie et Géodynamique UMR6112 (LPG), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Nantes - Faculté des Sciences et des Techniques, Université de Nantes (UN)-Université de Nantes (UN)-Université d'Angers (UA), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Cornell University, Consejo Superior de Investigaciones Científicas [Spain] (CSIC)-Instituto Nacional de Técnica Aeroespacial (INTA), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Centre National de la Recherche Scientifique (CNRS)-Observatoire de la Côte d'Azur, Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA), Royal Observatory of Belgium [Brussels], PSL Research University (PSL)-PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Centre National de la Recherche Scientifique (CNRS), School of Earth Sciences University of Bristol, Université Côte d'Azur (UCA)-Université Côte d'Azur (UCA)-Observatoire de la Côte d'Azur, and Université Côte d'Azur (UCA)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Seismometer, DISSIPATIVE FACTOR, 010504 meteorology & atmospheric sciences, FREE OSCILLATIONS, BULK COMPOSITION, Mars, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, Astronomy & Astrophysics, 01 natural sciences, Transfer function, Article, NETWORK SCIENCE, Autre, 0103 physical sciences, 0201 Astronomical and Space Sciences, INTERIOR STRUCTURE, ddc:530, Ground segment, 010303 astronomy & astrophysics, 0105 earth and related environmental sciences, InSight, Data processing, Science & Technology, Physics, Bandwidth (signal processing), Mars seismology, Astronomy and Astrophysics, Moment magnitude scale, SINGLE-STATION, THERMAL EVOLUTION, Mars Exploration Program, Geodesy, Space and Planetary Science, Physical Sciences, WAVE PROPAGATION, ELYSIUM PLANITIA, [SDU.OTHER]Sciences of the Universe [physics]/Other, Robotic arm, SEIS, Geology, METEORITE IMPACTS
Abstract

By the end of 2018, 42 years after the landing of the two Viking seismometers on Mars, InSight will deploy onto Mars’ surface the SEIS (Seismic Experiment for Internal Structure) instrument; a six-axes seismometer equipped with both a long-period three-axes Very Broad Band (VBB) instrument and a three-axes short-period (SP) instrument. These six sensors will cover a broad range of the seismic bandwidth, from 0.01 Hz to 50 Hz, with possible extension to longer periods. Data will be transmitted in the form of three continuous VBB components at 2 sample per second (sps), an estimation of the short period energy content from the SP at 1 sps and a continuous compound VBB/SP vertical axis at 10 sps. The continuous streams will be augmented by requested event data with sample rates from 20 to 100 sps. SEIS will improve upon the existing resolution of Viking’s Mars seismic monitoring by a factor of ∼2500 at 1 Hz and ∼200000 at 0.1 Hz. An additional major improvement is that, contrary to Viking, the seismometers will be deployed via a robotic arm directly onto Mars’ surface and will be protected against temperature and wind by highly efficient thermal and wind shielding. Based on existing knowledge of Mars, it is reasonable to infer a moment magnitude detection threshold of Mw∼3 at 40∘ epicentral distance and a potential to detect several tens of quakes and about five impacts per year. In this paper, we first describe the science goals of the experiment and the rationale used to define its requirements. We then provide a detailed description of the hardware, from the sensors to the deployment system and associated performance, including transfer functions of the seismic sensors and temperature sensors. We conclude by describing the experiment ground segment, including data processing services, outreach and education networks and provide a description of the format to be used for future data distribution., Space Science Reviews, 215 (1), ISSN:1572-9672, ISSN:0038-6308

Published
2019
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3. Geology and Physical Properties Investigations by the InSight Lander

Author

Sylvain Piqueux, Pierre Delage, William B. Banerdt, Ingrid Daubar, Nils Müller, Matthias Grott, Antoine Lucas, Tamara Gudkova, U. R. Christensen, Johan O. A. Robertsson, Don Banfield, Brigitte Knapmeyer-Endrun, T. Spohn, Suzanne E. Smrekar, Lucile Fayon, David Sollberger, Ralph D. Lorenz, Domenico Giardini, D. Kipp, G. Kargl, Matthew P. Golombek, Nicholas A Teanby, Sharon Kedar, B. Kenda, Ashitey Trebi-Ollennu, Raphaël F. Garcia, Ernst Hauber, Paul Morgan, Khaled Ali, Roy Lichtenheldt, Aymeric Spiga, Philippe Lognonné, Jason P. Marshall, Naomi Murdoch, David Mimoun, Cedric Schmelzbach, Joana Voigt, Constantinos Charalambous, Justin N. Maki, Veronique Ansan, William T. Pike, T. Nicollier, José E. Andrade, Mark P. Panning, Sebastien Rodriguez, Nicholas H. Warner, Institut Supérieur de l'Aéronautique et de l'Espace - ISAE-SUPAERO (FRANCE), Laboratoire de Planétologie et Géodynamique [UMR 6112] (LPG), Université d'Angers (UA)-Université de Nantes - UFR des Sciences et des Techniques (UN UFR ST), Université de Nantes (UN)-Université de Nantes (UN)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP), Centre National de la Recherche Scientifique (CNRS)-Université de La Réunion (UR)-Université Paris Diderot - Paris 7 (UPD7)-IPG PARIS-Institut national des sciences de l'Univers (INSU - CNRS), Département Electronique, Optronique et Signal (DEOS), Institut Supérieur de l'Aéronautique et de l'Espace (ISAE-SUPAERO), Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Institut Universitaire de France (IUF), Ministère de l'Education nationale, de l’Enseignement supérieur et de la Recherche (M.E.N.E.S.R.), Jet Propulsion Laboratory (JPL), NASA-California Institute of Technology (CALTECH), German Aerospace Center (DLR), Division of Engineering and Applied Science, California Institute of Technology, California Institute of Technology (CALTECH), School of Earth Sciences [Bristol], University of Bristol [Bristol], Interactions et dynamique des environnements de surface (IDES), Université Paris-Sud - Paris 11 (UP11)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Deutsches Zentrum für Luft- und Raumfahrt (DLR), Jülich Centre for Neutron Science (JCNS - PGI, JARA-FIT), Peter Grünberg Institut, Max-Planck-Institut für Sonnensystemforschung (MPS), Max-Planck-Gesellschaft, Cornell University, Departments of Anesthesiology and Physiology and Biophysics, University of Alabama at Birmingham [ Birmingham] (UAB), UNS-CNRS-Observatoire de la Côte d'Azur, Géotechnique (cermes), Laboratoire Navier (navier umr 8205), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux (IFSTTAR)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS), Department of Mechanical Engineering [Imperial College London], Imperial College London, University of Arizona, Astrophysique Interprétation Modélisation (AIM (UMR_7158 / UMR_E_9005 / UM_112)), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7), École normale supérieure - Paris (ENS Paris)-École normale supérieure - Paris (ENS Paris), University of Florida [Gainesville], Schmidt United Institute of Physics of the Earth [Moscow] (IPE), Russian Academy of Sciences [Moscow] (RAS), Departamento de Ecologia (CEAMISH), Universidad Autonoma del Estado de Morelos (UAEM), Institute of Geophysics [ETH Zürich], Department of Earth Sciences [ETH Zürich] (D-ERDW), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich)-Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology in Zürich [Zürich] (ETH Zürich), Institut National Polythechnique Houphouet Boigny, California Institute of Technology (CALTECH)-NASA, Laboratoire de Planétologie et Géodynamique UMR6112 (LPG), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Nantes - Faculté des Sciences et des Techniques, and Université de Nantes (UN)-Université de Nantes (UN)-Université d'Angers (UA)

Subjects
Seismometer, 010504 meteorology & atmospheric sciences, [SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph], Wind stress, Mars, 01 natural sciences, Wind speed, Seismic wave, [SDU.STU.PL]Sciences of the Universe [physics]/Earth Sciences/Planetology, Planetenphysik, 0103 physical sciences, Traitement du signal et de l'image, [SDU.STU.GM]Sciences of the Universe [physics]/Earth Sciences/Geomorphology, [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment, 010303 astronomy & astrophysics, Dust devil, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, InSight, Raumfahrt-Systemdynamik, Physical properties, Leitungsbereich PF, Astronomy and Astrophysics, Geology, Geophysics, Mars Exploration Program, Surface materials, InSight Mars Geology Physical properties Surface materials, Regolith, [SDU.ASTR.IM]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Instrumentation and Methods for Astrophysic [astro-ph.IM], Planetengeologie, Space and Planetary Science, Hesperian, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing
Abstract

International audience; Although not the prime focus of the InSight mission, the near-surface geology and physical properties investigations provide critical information for both placing the instruments (seismometer and heat flow probe with mole) on the surface and for understanding the nature of the shallow subsurface and its effect on recorded seismic waves. Two color cameras on the lander will obtain multiple stereo images of the surface and its interaction with the spacecraft. Images will be used to identify the geologic materials and features present, quantify their areal coverage, help determine the basic geologic evolution of the area, and provide ground truth for orbital remote sensing data. A radiometer will measure the hourly temperature of the surface in two spots, which will determine the thermal inertia of the surface materials present and their particle size and/or cohesion. Continuous measurements of wind speed and direction offer a unique opportunity to correlate dust devils and high winds with eolian changes imaged at the surface and to determine the threshold friction wind stress for grain motion on Mars. During the first two weeks after landing, these investigations will support the selection of instrument placement locations that are relatively smooth, flat, free of small rocks and load bearing. Soil mechanics parameters and elastic properties of near surface materials will be determined from mole penetration and thermal conductivity measurements from the surface to 3–5 m depth, the measurement of seismic waves during mole hammering, passive monitoring of seismic waves, and experiments with the arm and scoop of the lander (indentations, scraping and trenching). These investigations will determine and test the presence and mechanical properties of the expected 3–17 m thick fragmented regolith (and underlying fractured material) built up by impact and eolian processes on top of Hesperian lava flows and determine its seismic properties for the seismic investigation of Mars’ interior.

Published
2018
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4. The Magnetic Sun: Reversals and Long-Term Variations

Author

Kristof Petrovay and U. R. Christensen

Subjects
Physics, FOS: Physical sciences, Physics::Physics Education, Astronomy, Astronomy and Astrophysics, Astrophysics, Physics::Geophysics, Term (time), Astrophysics - Solar and Stellar Astrophysics, Space and Planetary Science, Physics::Space Physics, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Current (fluid), Solar dynamo, Solar and Stellar Astrophysics (astro-ph.SR)
Abstract

A didactic introduction to current thinking on some aspects of the solar dynamo is given for geophysicists and planetary scientists., 17 pages, 9 figures; Space Science Rev., in press

Published
2010
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5. Zonal flow driven by strongly supercritical convection in rotating spherical shells

Author

U. R. Christensen

Subjects
Convection, Physics, Natural convection, Convective heat transfer, Computer Science::Information Retrieval, Mechanical Engineering, Prandtl number, Thermodynamics, Rayleigh number, Mechanics, Condensed Matter Physics, Spherical shell, Physics::Fluid Dynamics, symbols.namesake, Mechanics of Materials, Zonal flow, symbols, Ekman number, Physics::Atmospheric and Oceanic Physics
Abstract

Thermal convection in a rotating spherical shell with free-slip boundaries can excite a dominant mean zonal flow in the form of differentially rotating cylinders concentric to the principal rotation axis. This process is studied numerically for Prandtl numbers of order 1, Ekman numbers in the range E = 3 × 10−4−10−5, and Rayleigh numbers up to 100× critical. Small-scale convection transfers kinetic energy into the mean zonal flow via Reynolds stresses. For low Ekman number and high Rayleigh number, the force balance is predominantly among the Coriolis, inertial and buoyancy forces, and viscosity plays a minor role. A modified Rayleigh number Ra* is introduced, which does not depend on viscosity or thermal diffusivity, and asymptotic scaling laws for the dependence of various properties on Ra* in the limit of negligible viscosity (E → 0) are estimated from the numerical results. The ratio of kinetic energy in the zonal flow to that in the non-zonal (convective) flow increases strongly with Ra* at low supercritical Rayleigh number, but drops at high values of Ra*. This is probably caused by the gradual loss of geostrophy of the convective columns and a corresponding decorrelation of Reynolds stresses. Applying the scaling laws to convection in the molecular hydrogen envelopes of the large gas planets predicts the observed magnitude of the zonal winds at their surfaces.

Published
2002
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7. An Eulerian technique for thermomechanical modeling of lithospheric extension

Author

U. R. Christensen

Subjects
Atmospheric Science, Soil Science, Aquatic Science, Classification of discontinuities, Oceanography, Mantle (geology), Physics::Geophysics, Physics::Fluid Dynamics, symbols.namesake, Geochemistry and Petrology, Asthenosphere, Lithosphere, Earth and Planetary Sciences (miscellaneous), Earth-Surface Processes, Water Science and Technology, Ecology, Deformation (mechanics), Paleontology, Forestry, Eulerian path, Mechanics, Geophysics, Pure shear, Simple shear, Space and Planetary Science, symbols, Geology
Abstract

A two-dimensional Eulerian spline function finite element method for modeling the coupled thermomechanical processes which control lithospheric extension is presented. The model domain comprises a cross section through the lithosphere and part of the asthenosphere. Material may enter or leave through the bottom and side boundaries. On the side boundary a fixed velocity or a fixed force condition can be applied. Highly nonlinear and thermally activated creep laws are used for the brittle and ductile rheologies of the lithosphere. Compositional differences between crust and mantle are described by a continuous function which is advected and which affects density, rheology, and heat production. An approximate topography is calculated from the normal stress at a free-slip surface boundary. A set of sample case studies is presented which highlights the capabilities and possible applications of the method. It also serves to study the influence of numerical parameters and of conceptual assumptions in various nontrivial applications. The examples comprise narrow rifting continuing into the stage of seafloor spreading, formation of a wide basin, formation of a metamorphic core complex, and impact of a mantle plume onto the bottom of the lithosphere. In the last case the entire upper mantle is modeled, and the instability of a thermal bottom boundary layer gives rise to a diapiric mantle plume. The main weakness of the Eulerian approach as compared to the Lagrangian technique was found to be the effective blurring of material discontinuities like the Moho. This is of little consequence in pure shear deformation, but when strong simple shear occurs, it impairs the resolution. The main advantage of the Eulerian technique is that very large deformation poses no problem as it does for the Lagrangian method. The new approach is especially suited to study processes where strong differential flow occurs in part of the modeled system. A further possible advantage of the method is its efficiency in terms of computer time.

Published
1992
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10. 3-D Images of the Eifel Plume, Germany

Author

J. R. R. Ritter, M. Jordan, U. Achauer, U. R. Christensen, EIFEL Plume Team, 2.4 Seismology, 2.0 Physics of the Earth, Departments, GFZ Publication Database, Deutsches GeoForschungsZentrum, and 2.2 Geophysical Deep Sounding, 2.0 Physics of the Earth, Departments, GFZ Publication Database, Deutsches GeoForschungsZentrum

Subjects
550 - Earth sciences
Published
2001

11. The Teleseismic Tomography Experiment in the Eifel Region, Central Europe: Design and First Results

Author

J. R. R. Ritter, U. Achauer, U. R. Christensen, Eifel Plume Team, 2.2 Geophysical Deep Sounding, 2.0 Physics of the Earth, Departments, GFZ Publication Database, Deutsches GeoForschungsZentrum, and 2.4 Seismology, 2.0 Physics of the Earth, Departments, GFZ Publication Database, Deutsches GeoForschungsZentrum

Subjects
geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, Crust, 550 - Earth sciences, Volcanism, Massif, 010502 geochemistry & geophysics, 01 natural sciences, Mantle (geology), Mantle plume, Geophysics, Volcano, Hotspot (geology), Intraplate earthquake, Geology, Seismology, 0105 earth and related environmental sciences
Abstract

The Eifel region is a mountain range belonging to the Rhenish Massif in central Europe. It is located in western Germany close to France, Luxembourg, and Belgium. The volcanic fields in the East Eifel and West Eifel (Figure 1) evolved in the last 600 ka, and the last eruptions occurred only 11-12 ka B.P. Twenty kilometers northwest of Koblenz the Laacher See volcano erupted at least 5 km3 of phonolitic magma (Bogaard and Schmincke, 1985) 12.2 ka ago—an amount that is comparable to the 1991 Pinatubo eruption. The intraplate volcanism in the Eifel region and the existence of further Tertiary volcanic fields in central Europe led Duncan et al. (1972) to the hypothesis that there is a hotspot track over an “Eifel plume.” Although the concept of this hotspot track is no longer accepted, various anomalies in the upper mantle support the existence of a mantle plume. Raikes and Bonjer (1983) revealed a low-velocity anomaly (∼-3%) at 50 km to 200 km depth beneath the Eifel region using teleseismic tomography. More recent tomographic images also contain a low-velocity zone in the upper 200 km of the mantle (Spakman et al., 1991; Passier and Snieder, 1997). Goes et al. (1999) proposed a deep magma source in the lower mantle based on global tomography. Meyer and Stets (1998) found evidence for up to 250 m uplift during the last 800 ka. Mineralogical and petrological studies indicate that the source of the magma is at least at 90 km depth. To obtain a detailed model of the processes in the upper mantle beneath the Eifel region a European interdisciplinary initiative was started. The scientific aim of the seismological contribution was to use all available techniques, such as high-resolution tomography, receiver functions, shear-wave splitting analysis, and crustal studies, to image the crust and …

Published
2000

13. Seismologische Untersuchungen in der Eifel

Author

T. Kaspar, Y. Temme, U. Achauer, G. Bock, G. Bokelmann, T. Camelbeek, U. R. Christensen, I. Eschghi, C. Förster, K. Hinzen, R. Pelzing, J. R. R. Ritter, Michael Weber, Eifel Plume Projekt, and 2.4 Seismology, 2.0 Physics of the Earth, Departments, GFZ Publication Database, Deutsches GeoForschungsZentrum

Subjects
550 - Earth sciences
Published
1998

14. Models of mantle convection: one or several layers

Author

U. R. Christensen

Subjects
Convection, Mantle convection, Subduction, Lithosphere, Oceanic crust, Stratification (water), Eclogite, Petrology, Geology, Mantle (geology)
Abstract

Numerical model calculations are used to determine if convection in the Earth’s mantle could be organized in two or more layers with only limited mass exchange in between. The seismic discontinuity at 670 km depth and the top of the D"-layer at the bottom of the mantle are considered as candidates for internal boundaries. If the 670 km discontinuity is caused by an isochemical phase transition, it has to have a Clapeyron slope of dp/dT ⩽ — 6 MPa k -1 to prevent convection currents from crossing; this value is improbably low. If the discontinuity represents a chemical boundary, the intrinsic density difference has to exceed 3 % to prevent subducted lithospheric slabs from penetrating deeply into the lower mantle; also the condition is possibly hard to meet. The least improbable mechanism for a mid-mantle barrier for convection currents would be a combination of endothermic phase transition and chemical change. The boundary between upper and lower mantle would show considerable topography, and a limited material exchange is to be expected at any rate. The possibility of a downward segregation of former oceanic crust, transformed to dense eclogite, is studied in a further model series. It requires a region of low viscosity, as the Delayer probably is, and is faciliated by the decrease of the thermal expansion coefficient with pressure. About 20% of subducted oceanic crust could accumulate at the core-mantle boundary. The dense material would concentrate underneath rising therm al plumes, and some of it is entrained into the plumes, possibly affecting their geochemical signature.

Published
1989
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15. A Machine for Adiabatic Toroidal Compression

Author

U. R. Christensen, J. C. Citrolo, J. G. Murray, and K. E. Wakefield

Subjects
Nuclear and High Energy Physics, Engineering, Toroid, Tokamak, business.industry, Nuclear engineering, Electrical engineering, Field strength, Radius, Compression (physics), law.invention, Nuclear Energy and Engineering, law, Electrical and Electronic Engineering, Adiabatic process, business, Gas compressor, Plasma stability
Abstract

The Adiabatic Toroidal Compressor (ATC) is being built to investigate the feasibility of a proposed technique for increasing the density and ion temperature of conventional tokamaks. By applying a suitable magnetic field normal to the plane of a usual tokamak discharge, the major radius is caused to shrink to about 0.4 of its original value, thereby resulting in an increase both in temperature and density. The experiment is important because, if successful, the technique could be applied to achieve plasma temperatures and densities significantly greater than otherwise obtainable in a given size facility. Selection of the machine size, field strength and time scale for the operating cycle was based both on the desire to achieve values of temperature and density well exceeding those already reported by others and on the conviction that experimental results should be forthcoming by mid-1972 to be useful in the design of larger experimental facilities. The first goal is expected to be met in the choice of a field strength of 50 kG at 37 cm major radius, the location of the 241 kA discharge after compression. The second goal required the use of presently available (or readily constructed) power supplies and an amount of engineering manpower consistent with existing laboratory programs. Buildup of the initial discharge within about 5 ms, a thermalizing time of up to 20 ms, and a compression time of about 2 ms are attainable within the above framework and are consistent with the energy replacement time of the plasma.

Published
1971
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17. A comparison of methods for the modeling of thermochemical convection

Author

Harro Schmeling, D. Neumeister, Scott D. King, Marie-Pierre Doin, P. E. van Keken, and U. R. Christensen

Subjects
Convection, Atmospheric Science, Convective heat transfer, Prandtl number, Soil Science, Thermodynamics, Aquatic Science, Oceanography, Instability, Mantle (geology), Isothermal process, Physics::Fluid Dynamics, Chaotic mixing, symbols.namesake, Geochemistry and Petrology, Earth and Planetary Sciences (miscellaneous), Rayleigh–Taylor instability, Earth-Surface Processes, Water Science and Technology, Physics, Ecology, Paleontology, Forestry, Mechanics, Geophysics, Space and Planetary Science, symbols
Abstract

We have compared several methods of studying thermochemical convection in a Boussinesq fluid at infinite Prandtl number. For the representation of chemical heterogeneity tracer, marker chain, and field methods are employed. In the case of an isothermal Rayleigh-Taylor instability, good agreement is found for the initial rise of the unstable lower layer; however, the timing and location of the later smaller-scale instabilities may differ between methods. For a simulation of entrainment by thermal convection of a dense layer at the bottom of the mantle we found good agreement for a few overturn times. After this, differences between the results can be large. We propose intrinsic differences between the methods and possibly chaotic mixing effects may be the cause of the lack of detailed agreement. The comparison shows that high resolution is necessary for a reasonable thermochemical study. This will pose severe restrictions on the applicability of these methods to three-dimensional situations.

18. Axisymmetric Minimum Average B Configuration of a Triply Connected System

Author

U. R. Christensen and S. Yoshikawa

Subjects
Physics, Toroid, General Engineering, Rotational symmetry, Torus, Mechanics, Plasma, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, Magnetic field, Conductor, Physics::Fluid Dynamics, Condensed Matter::Soft Condensed Matter, Shear (sheet metal), Classical mechanics, Axial symmetry
Abstract

An axially symmetric toroidal device with one floating conductor which has both minimum average B and high‐shear properties is described. Both magnetic well and shear can approach the theoretical maximum in this device.

Published
1966
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