Stephenson, W.R.; Chavez-Garcia, F.J. 1998 Preliminary assessment of resonant phenomena recorded by the Parkway Network. Lower Hutt: Institute of Geological & Nuclear Sciences. Institute of Geological & Nuclear Sciences science report 98/18 i, 63 p.
Abstract: Preliminary analysis of records of seven earthquakes obtained from the Parkway seismic network has revealed an unprecedented richness of effects. The network comprised 24 seismographs situated on and around a sedimentary basin 400m in diameter. Summing spectra over all soft soil stations and all the seven events considered shows that there are six favoured frequencies, two of which are separated by only 1.0Hz. Frequency-wavenumber analysis of vertical motion shows that for two earthquakes, waves travel along the basin in two different directions. These are probably Rayleigh waves. Waveform fitting shows that a pair of adjacent stations have identical resonant waveforms, indicating the excitation of normal modes. Frequency-phase analysis of resonant motion between a pair of adjacent stations shows long delays, probably indication energy interchange between normal modes. (auth)