Syllabus
* Makroseismic data
Ground motion and intensity, macroseismic scales, isoseismal maps. Historic and recent data.
* Instrumental data
Historic development of instruments; basic principles. Mechanical seismograph. Transfer function for input displacement, velocity, acceleration. Decibel, decade, octave. Short-period, long-period and broad-band instrument. Sensitivity (volt/(m/s)), digitization (volt/count) and final relation count/(m/s). Instrumental correction in practice. Sampling rate, triggering, data storage. Data formats. Seismic noise and instrumental noise. Reading seismograms (arrival time, polarity, amplitude, period, duration). Instrumentation of our department (station PRAHA and stations in Greece). CMG-3T velocigraph and 5T accelerograph; analysis by program SCREAM. Program PITSA. Getting data from world data centers (ISC, USGS, ORFEUS). Seismic web pages.
* Location and seismicity
Principles of linearized kinematic location. Programs HYPO. Principles of the grid-search location. Principles of the master-event (relative) location. Geometric azimuth and epicentral distance on the sphere. Rotation of horizontal components from EW, NS into R, T system. Particle motion (polarization) diagrams of P and S waves, S-wave splitting. Dynamic azimuth and incidence angle (apparent and true). Global and regional source regions. Depth distribution. Vadati-Benioff zones.
* Body waves
Elastic Lame parameters in isotropic medium, bulk modulus (incompressibility), Poisson ratio. Linearized equation of motion; stress-velocity formulation; displacement formulation. Separation of P and S waves in homogeneous media, divergence and curl; definition of Vp a Vs. Potentials. Longitudinal and shear waves. 2D equations of motion; separation of P-SV and SH waves. 3D equations of motion. Curved interfaces and free surface. Dissipation, Q-factor, attenuation and dispersion.
* Rays and travel times
Fermat principle. Snell's law. Parametric equations of the travel-time curve in 1D spherically symmetric medium. The ray parameter and the travel-time derivative. Theoretical travel times in a homogeneous mantle and core: P, PcP and PKP waves. Amplitude-distance curves. The Wiechert-Herglotz equation (without derivation). Travel times for a layer over half-space; MOHO; Pn and PmP waves. "Dictionary" of seismic phases. Standard travel-time curves and seismic models of the Earth (JB a IASP91). Principles of seismic tomography.
* Surface waves
Love waves for a layer over half-space; dispersion and depth dependence. Rayleigh waves (without derivation). Mantle waves. Dispersion curves for continents and oceans.
* Magnitude
Richter's magnitude. Magnitude from body and surface waves, calibration function. station correction. Frequency-magnitude relations (Gutenberg-Richter). Relations between magnitude and intensity. Relations between magnitude and energy. Time variations in the seismic energy release (sequences, swarm, Benioff graphs). Foreshocks and aftershocks. Seismic gaps. Quiescence. Migration.
* Seismic sources
Fault plane, rupture, slip. Fault and radiated wave field. Pure shear earthquakes. Non-shear components. Seismic moment tensor; scalar moment, P-T-N axes. Radiation pattern of P and S waves (without derivation). Take-off angles for global and regional problems. Focal mechanisms retrieval from first-motion polarities. Problems involved. Nodal planes; source angles - strike, dip, rake; conjugate solutions. Apparent source time function and fault length; corner frequency. Directivity due to rupture propagation. Apparent time function retrieved by means of aftershocks (empirical Green's function). Relation between the fault length, moment and stress drop.
* Energy of seismic waves
Volume density of kinetic and potential strain energy. Energy and power flux; formulation in stress and velocity, or in velocity only. Energy estimation from a single station. Relation between the P and S wave energy. Relation between energy, moment and stress drop. Moment magnitude.
* Seismic hazard
Empirical attenuation curves (relation between ground motion, distance and magnitude). Problems involved. Synthetic attenuation curves. Point-source and finite-source approach. Synthetic seismograms for anti-seismic design. Empirical and synthetic response spectra for anti-seismic design.
* Local site effects
Frequency-selective amplification ('resonance') and prolongation of ground motion in subsurface structures. Layered and basin structures. Spectral ratios with respect to reference station. Horizontal/vertical spectral ratios. Transfer function of 1-D models excited by plane waves. Numerical simulation of 1D, 2D and 3D site effects - a short introduction.
Annotation
Macroseismic and instrumental observations of earthquakes. Physical processes of earthquake sources.
Geographical and temporal distribution of earthquakes. Body and surface seismic waves in simple Earth models.
Inverse seismic problems. Seismic hazard, zoning and microzoning.