Shear velocity structure of the Northland Peninsula, New Zealand, inferred from ambient noise correlations

Abstract

Ambient noise correlation has been successfully applied in several cases to regions with dense seismic networks whose geometries are well suited to tomographic imaging. The utility of ambient noise correlation‐based methods of seismic imaging where either network or noise field characteristics are less ideal has yet to be fully demonstrated. In this study, we focus on the Northland Peninsula of New Zealand using data from five seismographs deployed in a linear pattern parallel to the direction from which most of the ambient noise arrives. Shear wave velocity profiles computed from Rayleigh and Love wave dispersion curves using the Neighborhood Algorithm are in good agreement with the results of a previous active source refraction experiment and a teleseismic receiver function and surface wave analysis. In particular, we compute a path‐averaged Moho depth of ∼28 km along a ∼250 km profile. The use of both Rayleigh and Love wave measurements enables us to estimate the degree of radial anisotropy in the crust, yielding values of 2–15%. These results demonstrate that ambient noise correlation methods provide useful geophysical constraints on lithospheric structure even for nonoptimal network geometries and noise field characteristics.