Określenie struktury skorupy ziemskiej na podstawie sejsmicznej funkcji odbioru

Wilde-Piorko M.

Przegląd Geofizyczny

50(1-2), 2005, 31-45

During a earthquake some energy is released as seismic waves. Seismograms, recordings of ground velocity deplacement, can be received even for very far earthquakes thanks to present sensitive seismometers. These recordings contain the information about a source, a structure of the earth interior on a ray-path and also about a structure beneath a seismic station. A receiver function is calculated from the seismograms of far events (epicentral distances 30°-90°) recorded by three-component seismic station, mainly by broad-band one. Deconvolving the vertical component of teleseismic P waves (P) from the horizontal one (radial or tangential) we can move out the instrument impulse response, effective source time function and the ray-path effects in the mantle from the seismograms. The receiver function contains only P-to-S converted phases (except the direct P wave) from the seismic discontinuities beneath the station. We can apply to the receiver function the inversion method or forward modelling to investigate the one-dimensional S-wave velocity structure beneath the station. Analysis of the receiver functions of the seismic stations for a passive seismic experiment TOR from Sweden, Denmark and Germany and for permanent stations: Suwałki (SUW) from north-east Poland, Moxa (MOX) from south-east Germany, Pruhonice (PRU) as well as Dobruska/Polom (DPC) and Moravsky Beroun (MORC) from central and north-east Czech shows the big differences of the tectonic structure in these areas. I have applied to calculated receiver functions one-dimensional time-domain linear inversion method (TOR experiment, SUW), three-dimensional trial-and-error forward modelling (MOX) and simultaneous determination of Moho depth and average Poisson's ratio in the crust (PRU, DPC and MORC).