Approximate recovery of residual displacement from the strong motion recordings of the 24 August 2016 Amatrice, Italy earthquake

Abstract

This paper presents an investigation into the residual ground displacements recorded on a strong motion network during the Mw 6.0 24 August 2016 Amatrice, Italy earthquake. The available accelerometric data from near field recording stations are processed using two different techniques to remove baseline offsets and retain the low frequency signal which depends on residual displacement. The first method uses acausal filtering to identify and retain a dominant pulse while the second method uses linear regression to remove velocity or displacement baseline trends. The results are compared to high-rate (1 and 10 Hz) global positing system (GPS) displacement waveforms, consensus GPS displacement offsets and crustal deformations detected by interferometric synthetic aperture radar (InSAR) satellite imaging. Since the GPS sensors are not all collocated with the accelerometers, the InSAR data is used for stations where no GPS results are available, or when the nearest GPS is far. It is shown that both methods investigated in this paper provide displacement waveforms with features matching those of the high-rate GPS. In addition, the residual displacement magnitudes are in good agreement with the consensus and InSAR displacements. The acceleration time series for the stations considered in this work are provided as an electronic supplement with this paper.