RELEVANCE OF RECEIVER FUNCTION TECHNIQUE IN SUBDUCTION ZONE (AVACHA BAY)

This paper elaborates on specific aspects of P- and S-receiver functions. The functions that are researched in this paper were calculated using waveforms obtained by three adjacent broadband seismic stations within the Avacha bay area in proximity to the subduction zone of the Pacific plate. The subduction zone in seismological context manifests as a layer of high seismic velocities, which are known to introduce a level of distortion to the receiver functions. To specify the level of this effect we parsed through two sets of P and S receiver functions in this research. The first set contains events that pass through and theoretically are affected by the subduction zone of the Pacific plate and the second set contains events that do not. The paper demonstrates that converted waves and their multiples formed at the boundaries of the high-velocity layer significantly affect P-receiver functions starting with 30-th second after the primary phase. However, no notable effects on S-receiver functions were revealed. Thus, we empirically confirm that [at least in the investigated area] local single-dimensional models are valid to be used for the inversion of the receiver functions to the depth of up to 200 km after which point the seismic noise produced by the subducting plate effectively limits the applicability of such models.