Combining Higher-Order Statistics and Array Techniques to Pick Low-Energy P-Seismic Arrivals

• Published in: Applied sciences Vol. 15; no. 3; p. 1172
• Main Authors: Messuti, Giovanni, Palo, Mauro, Scarpetta, Silvia, Napolitano, Ferdinando, Scotto di Uccio, Francesco, Capuano, Paolo, Amoroso, Ortensia
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01.02.2025
• Subjects: Algorithms; Arrays; automatic P-onset; Automation; Earthquakes; high-order statistics; Italy; Machine learning; Methods; microearthquakes; seismic array; Statistics; Wavelet transforms; Italy; Apennines
• ISSN: 2076-3417; 2076-3417
• DOI: 10.3390/app15031172

We propose the HOSA algorithm to pick P-wave arrival times on seismic arrays. HOSA comprises two stages: a single-trace stage (STS) and a multi-channel stage (MCS). STS seeks deviations in higher-order statistics from background noise to identify sets of potential onsets on each trace. STS employs various thresholds and identifies an onset only for solutions that are gently variable with the threshold. Uncertainty is assigned to onsets based on their variation with the threshold. MCS verifies that detected onsets are consistent with the array geometry. It groups onsets within an array by hierarchical agglomerative clustering and selects only groups whose maximum differential times are consistent with the P-wave travel time across the array. HOSA needs a set of P-onsets to be calibrated. These sets may be already available (e.g., preliminary catalogs) or retrieved from picking (manually/automatically) a subset of traces in the target area. We tested HOSA on 226 microearthquakes recorded by 20 temporary arrays of 10 stations each, deployed in the Irpinia region (Southern Italy), which, in 1980, experienced a devastating 6.9 Ms earthquake. HOSA parameters were calibrated using a preliminary catalog of onsets obtained using an automatic template-matching approach. HOSA solutions are more reliable, less prone to false detection, and show higher inter-array consistency than template-matching solutions.