CAN‐HK: An a Priori Crustal Model for the Canadian Shield

Abstract

Online Material: Tables of the crustal model and Generic Mapping Tools‐compatible files, and color versions of figures. Crustal structure, which can vary greatly over relatively short length scales depending on the tectonic setting, has the potential to significantly influence the data used to infer the deeper features of the Earth. In particular, commonly implemented teleseismic methods are sensitive to crustal velocity structure but are invariably incapable of resolving it. Moho depth has a first‐order effect on travel‐time residuals of teleseismic body waves (>1 s variation; e.g., Waldhauser et al. , 2002); and, for typical Rayleigh‐wave periods of <150 s, the crust can contribute 50% or more to the surface‐wave‐derived velocity variations (Ritsema et al. , 2004; Artemieva, 2011). Crustal structure can also significantly affect the correct extraction of radial anisotropy in surface‐wave studies (Ferreira et al. , 2010; Panning et al. , 2010). The use of a high‐resolution crustal model thus has the potential to markedly enhance studies of the mantle. There are a number of global crustal models in circulation, for instance CRUST5.1 (Mooney et al. , 1998), CRUST2.0 (Bassin et al. , 2000), and CRUST1.0 (Laske et al. , 2013). These may lack the resolution required for detailed local seismic studies, especially where there are significant lateral variations in crustal structure across short length scales (e.g., at ocean–continent transitions; Marone and Romanowicz, 2007). Moreover, global compilations often require assumptions regarding local geology to extrapolate structure to regions of poor coverage. The goal of this contribution is to present a unified 3D crustal model of the Canadian shield. The new model presented here, CAN‐HK, utilizes new passive broadband …