Model Specification

The AuSREM model is defined on a grid with spacing of 0.5 degree in latitude and longitude. For the zone from 90 E to 180 E and 50 S to the equator there are 18,000 grid points at any defined depth. Aspects of the model with coarser resolution such as mantle structure and crustal structure in the ocean are interpolated onto the 0.5 degree grid. Although visual presentation is based on pixels, the model is not cellular and values at any point are to be extracted via interpolation between the grid points.

The crust is represented through a layer structure at each gridpoint, with subsequent interpolation of discontinuities. The working model is based on the 6-layer crustal representation that has been used for receiver functions. Mantle structure is specified through depth slices at 25 km intervals.

The mantle model is transversely isotropic with different S velocities for SV and SH waves.

For both crust and mantle, additional quantities are derived from the primary fields so that a full representation of P wavespeed, S wavespeed, and density are provided.

A 50 km depth slice is provided that links the crustal and mantle models, since some of the thicker crust penetrates this depth.

Last updated 14 August 2018