Analysis of the source scanning algorithm with a new P-wave picker

A better automatic body-wave picker with broad applicability

“…The consistency of ratio methods using running mean or rms, and the advantages of RP/LP rms have already been shown for industrial applications (Chen, 2006;Wong et al, 2009) or tectonic events (Zahradník et al, 2015). In our broader study, the best responses are obtained with the methods based on rms calculations, polarization changes and correlation.…”

“…Theoretically, the minimal time span allowed between two peaks is dictated by the period of the first detected signal. In practice multiple peaks between subsequent P and S arrivals might be an issue for earthquake location (there are no such limitations with shift and stack methods, Kao and Shan, 2004;Zahradník et al, 2015). Time derivative and Kurtosis have been shown as reliable onset indicators for seismic wave detection (Baer and Kradolfer, 1987;Lomax et al, 2012); their maximum in the vicinity of the probability peak should give best estimates of arrival times.…”

“…TheS T /L T uses the averaged absolute value of the signal (Allen, 1982) or its envelope (Baer and Kradolfer, 1987). TheRP/LP uses the summed absolute values of the signal in the right and left part of a moving time window (Chen, 2006;Wong et al, 2009;Zahradník et al, 2015). In these C f , the ratio operator could be substituted by the correlation operator with two advantages: 1) the correlation outputs normalized values, whereas theRP/LP method gives values dependent on the input data, 2) correlation is a robust approximation of deconvolution.…”

“…Finally, we follow preexisting work for multi-scaling with multiple C f to reduce the dependence on time-scale parameters. We compare our results with three C f (S T /L T , C rms andRP/LP, Zahradník et al, 2015) and propose an optimal approach.…”

Automatic Bayesian polarity determination

“…Therefore, it may be better to use a phase picker to determine the onset and construct the arrival-time PDF more accurately. There are many approaches to accurate onset pickers such as the methods discussed by Baer & Kradolfer (1987): STA/LTA pickers (Allen 1978(Allen , 1982Trnkoczy 2012); auto-regressive pickers (Takanami & Kitagawa 1988, 1991Nakamura 2004); stationary analysis pickers (Nakamula et al 2007); kurtosis based pickers (Hibert et al 2014;Ross & Ben-Zion 2014); right to left pick averaging (RPA/LPA) (Zahradník et al 2014), as well as many others. Withers et al (1998) provide an overview of several of these different approaches, as do Di Stefano et al (2006).…”