Seismic data of a rockslide: Evaluation of noise levels, site effects, frequency content and identification of seismic phases

Abstract

Seismic data can provide information to deduce the occurrence of mass movement events, their release time, event location and dynamics characterization [1]. Nevertheless, the effect of local site amplifications, the level of seismic noise and the frequency content of the signals are important constraints to correctly identify and describe these types of events. In this article we provide data on: site effects, power spectral densities, polarization particle motion and spectrograms generated by a rockslide (∼450 m3) (hereinafter NR) recorded in two permanent seismic stations (EPOB and POBL) located ∼10 km from the source. Original data are available through the International Federation of Digital Seismograph Networks (FDSN, http://www.fdsn.org) for POBL and on request from Instituto Geográfico Nacional (IGN, http://www.ign.es) for EPOB. POBL and EPOB site effects analysis by means of Horizontal-to-Vertical spectral ratio (H/V) technique shows important signatures in POBL signal between 1 and 10 Hz, indicating strong amplification effects at these frequencies, not present in EPOB. For frequencies >1 Hz, Power Spectral Densities (PSD) are higher in POBL than in EPOB, indicating that POBL is noisier than EPOB. Based on the H/V and PSD analyzes, the EPOB station data was deemed preferable over the POBL, to conduct the research presented in the related article [1]. Particle polarization motion data enabled the identification of the arrivals of P, S, and superficial waves, confirming that Pg waves were correctly identified, providing necessary information for the event location in the research article [1]. Moreover, EPOB and POBL spectrograms together with the Fourier transform are included to analyze their content in the frequency domain showing that the expected high frequency phenomenon of the rockslide recorded at 10 km is attenuated and only the low frequency content between 1 and 15 Hz is recorded.