Jean-Claude Mareschal Fiona Darbyshire Course outline Age and formation of Earth and planets. Origin of the elements. Formation of the moon. The early Earth. Geochronology. (JCM) Shape and rotation of the Earth. Tides. (JCM) The gravity field of Earth. Gravity anomalies. Isostasy. (JCM) Heat flow, thermal regime, and the energy budget of the Earth. (JCM) Earth’s magnetic field. The geodynamo. (JCM) Seismic wave propagation. Body and surface waves. Free oscillations. (FD) Seismicity of the Earth. Earthquake focal mechanisms. (FD) Plate tectonics. (FD) Seismic tomography: implications for geodynamics and mantle convection. (FD) Course objectives What do we want to know about Earth interior? Physical properties (density, elastic properties, viscosity, electrical conductivity, …) Pressure, temperature at depth Chemical composition Physical state (liquid, solid) Equation of state How did it come to be what it is today? How does it work? Feynman’s Lectures on Physics (1962) Some references Davies, G. F. Dynamic Earth: Plates, Plumes and Mantle Convection, Cambridge University Press, 2000. Fowler, CMR, The Solid Earth: An Introduction to Global Geophysics, 2nd Edition, Cambridge, University Press, 2004. Stacey, F.D., and Davis, P., Physics of the Earth, 4th Edition, Cambridge University Press, 2008. Bott, M.H.P. The interior of the Earth, 2nd Edition, Edward Arnold, London, 1982 Useful information Instructors: Fiona Darbyshire (20 October-1 December) darbyshire.fiona_ann@uqam.ca, f.darbyshire@gmail.com 514-987-3000x5054 Jean-Claude Mareschal (1 September-13 October) mareschal.jean-claude@uqam.ca, jeanclaude.mareschal@gmail.com 514-987-3000x6864 Evaluation: Midterm: 40% (15 October) Final: 40% (TBA) Homeworks: 20% Units. Numbers. SI unit Practical unit Conversion factor length m Light year Parsec 1 LY= 1013km 1 pc = 3.1 1013km Mass kg Time s yr 1 yr = 3.15 107s acceleration ms-2 Gal (cm s-2), mGal 1 mGal = 10-5 ms-2 Force N (kg m s-2) Energy J (kg m2 s-2) Calorie 1 cal =4.18J Power W (J s-1) Pressure Pa (N m-2) bar, kbar 1 kbar= 108 Pa Viscosity Pa s poise 1 poise = 0.1 Pa s Temperature K deg C T(C)= 273 +T(K) Physical constants. c 300,000 km s-1 G 6.67 10-11 N m2 kg-2 NA (Avogadro) 6.02 1023 mol-1 R (Gaz constant) 8.31 J mol-1 K-1 k (Boltzman) = R/NA 1.38 10-23J K-1 Numbers. Mass Earth 5.97 1024 kg Mean density 5,515 kg m-3 Mass Sun/Mass Earth 332,947 Mass Earth/Mass Moon 81 Solar density 1,408 kg m-3 Moon density 3.341 kg m-3 Numbers. Distance Time Atomic unit 10-15 Solar day 86,400 s Astronomical day 86,146 s Last glaciation 10,000 yr Man 2-4 Myr Earth 4.5 Gyr Universe ~15 Gyr s Earth radius ~6,400 km Earth-Moon ~400,000 km Earth-Sun ~150 106 km (8 min) Nearest star ~ 4 LY Galaxy 100,000 LY Nearest galaxy 1,000,000 LY Universe 1010 LY