Passive seismic imaging with directive ambient noise: application to surface waves and the San Andreas Fault in Parkfield, CA

Abstract

International audienceThis study deals with surface waves extracted from microseismic noise in the (0.1–0.2 Hz) frequency band with passive seismic-correlation techniques. For directive noise, we explore the concept of passive seismic-noise tomography performed on three-component sensors from a dense seismic network. From the nine-component correlation tensor, a rotation algorithm is introduced that forces each station pair to re-align in the noise direction, a necessary condition to extract unbiased traveltime from passive seismic processing. After rotation is performed, the new correlation tensor exhibits a surface wave tensor from which Rayleigh and Love waves can be separately extracted for tomography inversion. Methodological aspects are presented and illustrated with group-speed maps for Rayleigh and Love waves and ellipticity measurements made on the San Andreas Fault in the Parkfield area, California, USA

Seismic fault zone trapped noise

“…Evidence for ambient noise‐FZ interaction comes from progressive alignment of propagation directions with the fault normal (Figure b, red) and from short‐range variations within the LVZ (Figure c, red). This indicates that ray bending [ Roux , ] can potentially bias travel time inversions in FZ environments at wavelengths comparable to the LVZ width λ 0 .…”

“…The ambient seismic wavefield in a FZ environment is characterized by frequency‐dependent superposition of scattered, guided, bended, and reflected surface and body wave components. Several studies used correlations of ambient seismic noise to image FZ environments [ Roux et al , ; Roux , ; Hillers et al , ; Zigone et al , ] at wavelengths ( λ ) that are large compared to the width of the low‐velocity FZ damage zone ( λ 0 ). Fault zone head and trapped waves propagating along velocity contrast interfaces and the damage zone provide high‐resolution information on the internal components of fault structures [ Ben‐Zion and Aki , ; Li et al , ; Lewis and Ben‐Zion , ].…”

Passive monitoring of anisotropy change associated with the Parkfield 2004 earthquake

“…[6] Pre-processing of the data follows Roux [2009] (see auxiliary material for a detailed description in Figure S1) and is summarized here.…”

Transdimensional Love-wave tomography of the British Isles and shear-velocity structure of the East Irish Sea Basin from ambient-noise interferometry

“…The resulting method of ambient-noise tomography (ANT) makes use of information retrieved from ambient-noise cross-correlations, rather than earthquake records, to invert for subsurface structure. First applied to observational data by Shapiro et al (2005) and Sabra et al (2005), ANT has been used at regional and continental scales to produce group-velocity maps using mainly Rayleigh-wave cross-correlations, but a number of studies have also used Love-wave cross-correlations to image Europe (Li et al 2010a), Asia (Cho et al 2007;Li et al 2010b), North America (Bensen et al 2008;Lin et al 2008;Roux 2009), and Australia (Saygin & Kennett 2010). In addition, ANT has been used successfully to produce images of smaller-scale structures such as volcanic edifices (Masterlark et al 2010;Jay et al 2012;Nagaoka et al 2012) and inhomogeneities in oil and gas fields (Haney & Douma 2010, as well as of local structures at engineering seismology scales (Picozzi et al 2009;Pilz et al 2012) and on the seabed (de Ridder & Dellinger 2011;Mordret et al 2013a,b;de Ridder et al 2014).…”