Towards an automated Kappa measurement procedure

Abstract

We present an automatic algorithm for measuring the high-frequency acceleration spectral decay parameter (κ) on seismic records of strong ground motion. This task is often done manually due to the strongly varying quality and characteristics of earthquake recordings, such that an adaptive algorithm is required to mostly reproduce manual measurements but in a less subjective way. We prepended a P- and S-phase picking algorithm to achieve complete automation, and we discuss the common pitfalls for such attempts regarding both algorithms. To test the measurement schemes, a dataset of accelerograms from South Icelandic earthquakes is used on which all parameters have been determined manually as well. The proposed program facilitates automatic creation of κ-value databases from input record databases, which might be used in regional hazard analyses and to better constrain earthquake source parameter inversions.