Skip to main content

Research Repository

Advanced Search

Outputs (34)

GEORGIA: A Graph Neural Network Based EmulatOR for Glacial Isostatic Adjustment (2023)
Journal Article
Lin, Y., Whitehouse, P. L., Valentine, A. P., & Woodroffe, S. A. (2023). GEORGIA: A Graph Neural Network Based EmulatOR for Glacial Isostatic Adjustment. Geophysical Research Letters, 50(18), https://doi.org/10.1029/2023gl103672

Glacial isostatic adjustment (GIA) modeling is not only useful for understanding past relative sea-level change but also for projecting future sea-level change due to ongoing land deformation. However, GIA model predictions are subject to a range of... Read More about GEORGIA: A Graph Neural Network Based EmulatOR for Glacial Isostatic Adjustment.

Emerging Directions in Geophysical Inversion (2023)
Book Chapter
Valentine, A. P., & Sambridge, M. (2023). Emerging Directions in Geophysical Inversion. In A. Ismail-Zadeh, F. Castelli, D. Jones, & S. Sanchez (Eds.), Applications of Data Assimilation and Inverse Problems in the Earth Sciences (9-26). Cambridge University Press. https://doi.org/10.1017/9781009180412.003

In this chapter, we survey some recent developments in the field of geophysical inversion. We aim to provide an accessible general introduction to the breadth of current research, rather than focussing in depth on particular topics. In particular, we... Read More about Emerging Directions in Geophysical Inversion.

Observations and models of dynamic topography: Current status and future directions (2023)
Book Chapter
Davies, D. R., Ghelichkhan, S., Hoggard, M., Valentine, A. P., & Richards, F. D. (2023). Observations and models of dynamic topography: Current status and future directions. In J. Duarte (Ed.), Dynamics of plate tectonics and mantle convection (223-270). Elsevier. https://doi.org/10.1016/B978-0-323-85733-8.00017-2

The slow creeping motion of Earth’s mantle drives transient changes in surface topography across a variety of spatial and temporal scales. Recent decades have seen substantial progress in understanding this so-called `dynamic topography’, with a grow... Read More about Observations and models of dynamic topography: Current status and future directions.

Overcomplete tomography: a novel approach to imaging (2023)
Journal Article
Turunçtur, B., Valentine, A., & Sambridge, M. (2023). Overcomplete tomography: a novel approach to imaging. RAS Techniques and Instruments, 2(1), 207-215. https://doi.org/10.1093/rasti/rzad010

Regularized least-squares tomography offers a straightforward and efficient imaging method and has seen extensive application across various fields. However, it has a few drawbacks, such as (i) the regularization imposed during the inversion tends to... Read More about Overcomplete tomography: a novel approach to imaging.

Reply to comment on Geophysical inversion and Optimal Transport, 231, 172–198, by Okazaki & Ueda (2023)
Journal Article
Sambridge, M., Jackson, A., & Valentine, A. P. (2023). Reply to comment on Geophysical inversion and Optimal Transport, 231, 172–198, by Okazaki & Ueda. Geophysical Journal International, 233(2), 1488-1491. https://doi.org/10.1093/gji/ggad002

Concerns raised by Okazaki & Ueda (2022) on the paper by Sambridge et al. (2022) are addressed. Two issues are discussed and some new numerical results presented. The first concerns whether the properties of the Wasserstein time-series misfit introdu... Read More about Reply to comment on Geophysical inversion and Optimal Transport, 231, 172–198, by Okazaki & Ueda.

pyprop8: A lightweight code to simulate seismic observables in a layered half-space (2022)
Journal Article
Valentine, A. P., & Sambridge, M. (2022). pyprop8: A lightweight code to simulate seismic observables in a layered half-space. The Journal of Open Source Software, 7(76), Article 4217. https://doi.org/10.21105/joss.04217

The package pyprop8 enables calculation of the response of a 1-D layered halfspace to a seismic source, and also derivatives (‘sensitivity kernels’) of the wavefield with respect to source parameters. Seismograms, seismic spectra, and measures of sta... Read More about pyprop8: A lightweight code to simulate seismic observables in a layered half-space.

Geophysical inversion and optimal transport (2022)
Journal Article
Sambridge, M., Jackson, A., & Valentine, A. P. (2022). Geophysical inversion and optimal transport. Geophysical Journal International, 231(1), 172-198. https://doi.org/10.1093/gji/ggac151

We propose a new approach to measuring the agreement between two oscillatory time series, such as seismic waveforms, and demonstrate that it can be employed effectively in inverse problems. Our approach is based on Optimal Transport theory and the Wa... Read More about Geophysical inversion and optimal transport.

Upscaling and downscaling Monte Carlo ensembles with generative models (2022)
Journal Article
Scheiter, M., Valentine, A., & Sambridge, M. (2022). Upscaling and downscaling Monte Carlo ensembles with generative models. Geophysical Journal International, 230(2), 916-931. https://doi.org/10.1093/gji/ggac100

Monte Carlo methods are widespread in geophysics and have proved to be powerful in non-linear inverse problems. However, they are associated with significant practical challenges, including long calculation times, large output ensembles of Earth mode... Read More about Upscaling and downscaling Monte Carlo ensembles with generative models.

Structure and properties of alkali aluminosilicate glasses and melts: insights from deep learning (2021)
Journal Article
Le Losq, C., Valentine, A., Mysen, B. O., & Neuville, D. R. (2021). Structure and properties of alkali aluminosilicate glasses and melts: insights from deep learning. Geochimica et Cosmochimica Acta, 314, 27-54. https://doi.org/10.1016/j.gca.2021.08.023

Aluminosilicate glasses and melts are of paramount importance for geo- and materials sciences. They include most magmas, and are used to produce a wide variety of everyday materials, from windows to smartphone displays. Despite this importance, no ge... Read More about Structure and properties of alkali aluminosilicate glasses and melts: insights from deep learning.

Inferring material properties of the lower mantle minerals using Mixture Density Networks (2021)
Journal Article
Rijal, A., Cobden, L., Trampert, J., Jackson, J. M., & Valentine, A. (2021). Inferring material properties of the lower mantle minerals using Mixture Density Networks. Physics of the Earth and Planetary Interiors, 319, Article 106784. https://doi.org/10.1016/j.pepi.2021.106784

Interpretation of information available from seismic data in terms of temperature and composition requires an understanding of the physical properties of minerals, in particular, the elastic properties of candidate Earth minerals at the relevant (her... Read More about Inferring material properties of the lower mantle minerals using Mixture Density Networks.