The amplitudes of direct P and S waves of earthquakes are in principle influenced by the earthquake source mechanism, seismic attenuation and also by the P and S wave velocities of the rock medium. Depending on the available data and models adopted, the analysis of S/P amplitude ratios allows for determining the first two of these quantities. Recent observations show that the mean S/P amplitude ratios of the swarm earthquakes in Reykjanes (Iceland) and West Bohemia (Czechia) differ significantly. A question for the origin of this discrepancy can be answered by systematic study, correcting for the effect of source mechanisms and inverting for the ratio of P and S wave attenuation factors.
The PhD candidate will employ his background in seismology and numerical and programming skills to unravel the presented problem. First, characteristics of the S/P amplitude ratios will be quantified for the waveform datasets not only from Reykjanes and West Bohemia, but also for available data from other regions. The influence of focal mechanisms and different P and S wave attenuation to the observed amplitude ratios will be assessed in a synthetic study. The expected results will interpret the observations and contribute to better understanding of effect of the geologic structure and crustal fluids to the seismic wave amplitudes and vice versa - to the inversion for focal mechanisms.Deadline is closed