Introduction to Earthquakes Seismology

Introduction to Earthquakes Seismology

Luis RIVERA

Alessia MAGGI

This class presents an introduction to the study of earthquakes. We develop an approach pairing theory and observations.

Introduction : Plate tectonics and earthquakes, plate kinematics, global seismicity, strain, stresses, rheology, fracture.

Elastodynamics : Elastodynamic equations, explosive source, punctual force, punctual dislocation, fault representation, equivalent forces, double couple, near and far field. Influence of the medium properties, P and S polarization and radiation pattern, variation with the distance, source time function.

Focal Mechanism : Fault classification, punctual fault parametrization, focal sphere, remarkable points and planes. Nodal point ambiguity, plane representation of the focal sphere.

Source spectrum : seismic moment, earthquake magnitudes (Ml, Ms, Mw), corner frequency, scaling laws, radiated energy, finite sources (directivity), stress drop.

Inverse problems : Focal mechanism from first motion polarities,stress tensor from focal mechanisms,  introduction to the wave form modeling for finite source inversion.

Seismological instrumentation : microseismic noise, Electromagnetic seismometer response, feed-back, A/D converters, decimation filters, Poles and zeros.