Introduction to thermal-mechanical lithosphere models with surface processes
Louis Moresi and Romain Beucher, University of Melbourne
Surface processes including erosion, transport and sedimentation have the potential to strongly influence crustal and lithospheric deformation whether passively, through isostatic response, or more actively by affecting the thermal structure, the potential energy field, and / or the local stress field. Thermo-mechanical models have proven to be valuable tools to understand the processes involved during deformation of the lithosphere. Coupling state of the art thermo-mechanical models to surface processes model is not without challenges. In this webinar we will briefly give an overview of why we think surface processes must be taken into account, how it can be done using numerical models and what are the remaining challenges. The webinar will cover a range of geodynamic contexts and will present some new models of rifts. [pdf]
Introduction to Quagmire
Louis Moresi, University of Melbourne
Ben Mather, University of Sydney
Quagmire is an open source, parallel python module for modelling surface processes and landscape evolution. It comes from the Underworld geodynamics group and has many common design patterns to Underworld. For starters, this is not an out-of-the-box landscape evolution code — it is instead a collection of high level classes that can form parallel triangulations, gradient formation, stream-power calculations, catchment computation, lake detection etc. all of which can be used to write compact landscape codes in python. Quagmire also provides the concept of meshes and mesh variables that we try to make as similar as possible to the comparable concept in Underworld. Quagmire is a work in progress but gradually growing. We would like to encourage people to use the tools and contribute ideas.
Conducting Reproducible Science with Sciunits
Tanu Malik, DePaul University
Eunseo Choi, University of Memphis
Science is conducted collaboratively and often requires sharing of computational experiments. An experiment often includes diverse elements such as software, its past execution, provenance, and associated documentation. The notion of a ``research object’’ implies aggregation and identification of such diverse elements of computational experiments. Mere aggregation is, however, not sufficient for the sharing of computational experiments. Other users must be able to easily recompute on these shared research objects. We will present the "sciunit'', a reusable research object in which aggregated content is tracked, secured and made recomputable in different environments. We describe a Git-like client that efficiently creates, stores, repeats, and reproduces sciunits. We show that sciunits repeat computational experiments with minimal storage and processing overhead.
We will show how Sciunts improve reproducibility in computational hydrology with Hydroshare.org, an online collaboration environment for sharing data, models, and code. Researchers create sciunits on their local machines and add hydrology-specific metadata to these sciunits using Hydroshare’s API. Tools like CyberGIS and JupyterHub that have been integrated with HydroShare make sciunits reusable to run models using notebooks, Docker containers, and cloud resources. We will report on lessons learned and how sciunits can be used to improve the practice of maintaining Findable, Accessible, Interoperable, and Reusable (FAIR) computational experiments across all geoscience domains. Finally, we will report on complexity of computational experiments in the domains of solid earth and space science and unmet validation and documentation challenges in maintaining and using sciunits. [pdf]
TerraFERMA: a framework for rapidly building finite element models in geodynamics
Cian Wilson, Carnegie Science, DTM,
Modern, advanced, open-source computational libraries are giving an increasing amount of power to researchers to develop customized numerical models, tailor made for individual problems. While incredibly powerful and flexible, this approach raises questions about the reliability and maintainability of scientific models when each new problem is solved using a new script or piece of code. During this seminar we will discuss TerraFERMA, a model building framework built on the FEniCS, PETSc and SPuD libraries, that aims to increase the maintainability of models by providing a common core to all models designed using TerraFERMA's interface. This core library allows updates to the underlying libraries to be implemented largely unseen by the user and for new functionality to be made available to all existing models without having to edit each one individually. Along with an extensive test suite, it also ensures that verifying one model provides some trust in another. We will discuss our goals in designing TerraFERMA, give a brief overview of its structure, demonstrate some examples of its use and discuss our future development goals.
HeFESTO: A tool for exploring Earth’s physical properties and their effects on mantle dynamics
Carolina Lithgow-Bertelloni, UCLA
The minerals that exist at the extreme pressure and temperature conditions of the mantle and their physical properties determine the dynamics of the mantle. Both are also critical for comparison with seismic observations that put constraints on our knowledge of mantle structure and composition.
We have developed a thermodynamic model of mantle minerals that allows us to robustly predict mantle phase assemblages and self-consistently their equilibrium properties. Our model is embodied in the code HeFESTo, which I will describe during this webinar. I will discuss briefly the theoretical underpinnings of our thermodynamic approach and how the code can be used. I will also discuss our latest results and focus on the effective thermal expansion of phase assemblages and their effect on convection. [pdf]
Thermodynamic calculations and model generation using ENKI
Mark Ghiorso, OFM Research
ENKI is a collaborative, web-based model-configuration and testing portal that provides tools in computational thermodynamics and fluid dynamics. The ENKI platform utilizes a Jupyter Lab/Hub interface to access underlying modeling tools using Python. ENKI provides a standard interface to commonly used thermodynamic databases and to computational thermodynamic modeling tools. It may also be used to generate and calibrate new thermodynamic models. A brief overview of the ENKI platform will be given and several examples illustrating ENKI modeling capabilities will be illustrated.