Dr Ben Mather and Prof Louis Moresi from AuScope’s Simulation, Analysis and Modelling (SAM) program have recently developed a novel, speedy and data-driven way to model the temperature of Earth’s crust in southeastern Australia. Their work has since attracted a grant from the International Association of Mathematical Geosciences (IAMG) to refine the new method and investigate earth temperatures further afield in Alaska.

An efficient inversion framework that gives improved estimates of the thermal state of the crust in Victoria using heat flow measurements and Curie depth in a joint inversion using 3D geological models, and numerical models of thermal diffusion. The outcome of this work is an estimation of the basal heat flux, thermal properties and the heat production rates for the various domains in the model together with uncertainty information.

The temperature distribution in the crust, and associated uncertainty, was simulated from the ensemble of Curie depth realisations assigned to a lower thermal boundary condition of a crustal model (inc. sedimentary thickness, Moho depth, heat production, thermal conductivity), constructed from various geophysical and geochemical data sets.

One common method to determine heat flow in a well is to use a Bullard plot, which graphs thermal resistance (m$^2$K W$^{-1}$) against temperature. The gradient of this line is heat flow, and the uncertainty determined from the error of linear regression.
Thermal resistance is calculated by:
$$ R = \sum_{i=0}^{n} \left( \frac{\Delta z_i}{k_i} \right) $$
which is the cumulative summation of resistors down the length of a borehole. The uncertainty on $R$ should increase as the individual errors on $k$ accumulate.

Regions where surface temperature has increased since past glaciation events, such as Ireland, underestimate the heat output of the Earth unless palaeoclimate corrections are applied. We apply probabilistic techniques to quantify the uncertainty of …

The surface heat flow field in Australia has for many years been poorly constrained compared to continental regions elsewhere. 182 recent heat flow determinations and 66 new heat production measurements for Southeastern Australia significantly …

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