Australian Seismological Reference Model (AuSREM): mantle component

The mantle component of the Australian Seismological Reference Model (AuSREM) has been constructed from Australian-specific sources, primarily exploiting the wealth of seismic sources at regional distances around Australia recorded at portable and permanent stations on the continent. AuSREM is designed to bring together the existing information on Australia, from both body wave and surface wave studies and provide a synthesis in the form of a 3-D model that can provide the basis for future refinement. The model is grid based with a 0.5° sampling in latitude and longitude, and is designed to be fully interpolable, so that properties can be extracted at any point. For the upper mantle the primary source of information comes from seismic surface wave tomography, supplemented by analysis of body wave arrivals and regional tomography which provide useful constraints on the relation between P- and S-wave speeds in the mantle lithosphere. A representative model has been developed to capture the features of mantle structure drawing on a range of studies. The mantle structure is represented by grid values at 25 km intervals in depth from 75 to 300 km. Shallower structure is linked to the AuSREM crust through the recent Moho depth model of Kennett et al., which exploits all available sources of seismological information. Below 300 km depth and in the surrounding area AuSREM is linked to the S40RTS model of Ritsema et al.