Tectonic tremor characterized by principal-component analysis in the vicinity of central Chile and Argentina. (October 2019)

• Record Type: Journal Article
• Authors: Nishitsuji, Yohei; Marín, Luis Franco; Gomez, Martín; Rowe, C.A.; Draganov, Deyan
• Is Part Of: Journal of South American earth sciences. Volume 94(2019)
• Publication Date: 2019-10
• Subjects: Geophysics -- Tectonic tremor -- Principal-component analysis -- Cross-correlation -- Argentina; Geology -- Latin America -- Periodicals; Earth sciences -- Latin America -- Periodicals; Geology -- Antarctica -- Periodicals; Earth sciences -- Antarctica -- Periodicals; Geology -- Caribbean Area -- Periodicals; Earth sciences -- Caribbean Area -- Periodicals; Géologie -- Amérique latine -- Périodiques; Sciences de la terre -- Amérique latine -- Périodiques; Géologie -- Antarctique -- Périodiques; Sciences de la terre -- Antarctique -- Périodiques; Géologie -- Caraïbes (Région) -- Périodiques; Sciences de la terre -- Caraïbes (Région) -- Périodiques; Earth sciences; Geology; Antarctica; Caribbean Area; Latin America; Periodicals; 550.5
• DOI: 10.1016/j.jsames.2019.04.022
• Languages: English
• ISSNs: 0895-9811

Abstract

Abstract: No conclusive evidence has been presented to date for tectonic tremor (TT) in the vicinity of central Chile, where the Nazca Plate is subducting beneath the South American Plate. Subduction in our experimental location (roughly 35.5° S, 70.5° W) is steep and fairly unobstructed compared to the flattened and more seismogenic behavior to the north. We seek to identify TT in our experimental area, whose geodynamics are comparable to tremor-rich subduction zones such as Cascadia and the Nankai Trough. Our method combines time-series visual inspection, frequency-spectrum analysis, waveform cross-correlation, and 3-component (3C) signal covariance to explore the presence of TT in this region. We have identified TT using stations in central Chile and the Malargüe region, Argentina. The TT exhibits similar features to other TT observations worldwide. Waveform characteristics for the TT in our study, particularly dimension of the 3C signal covariance, vary as a function of apparent source location. The duration of one episode of identified TT was about 10 h, which may indicate that the plate interface where tremor generates is strongly coupled. We conclude that our observations reflect features of the local propagation, rather than the tremor source itself. Highlights: Tectonic tremor is identified in central Chile and central western Argentina. Principal-component analysis of 3-component signal helps for seismic characterization. Identified tremor duration suggests strong coupling of plate interface.