Volcanic and Seismic Source Modeling: An Open Tool for Geodetic Data Modeling

Abstract

Volcanic and Seismic source Modeling (VSM) is an open-source Python tool to model ground deformation. VSM allows the user to choose one or more deformation sources of various shapes as a forward model among sphere, spheroid, ellipsoid, rectangular dislocation, and sill. It supports multiple datasets from most satellite and terrestrial geodetic techniques: Interferometric SAR, GNSS, leveling, Electronic Distance Measurements, tiltmeters, and strainmeters. Two sampling algorithms are available: one is a global optimization algorithm based on the Voronoi cells and yields the best-fitting solution and the second follows a probabilistic approach to parameters estimation based on the Bayes theorem and the Markov chain Monte Carlo method. VSM can be executed as Python script, in Jupyter Notebook environments, or by its Graphical User Interface. Its broad applications range from high-level research to teaching, from single studies to near real-time hazard estimates. Potential users range from early-career scientists to experts. It is freely available on GitHub (https://github.com/EliTras/VSM) and is accompanied by step-by-step documentation in Jupyter Notebooks. This study presents the functionalities of VSM and test cases to describe its use and comparisons among possible settings.

Versatile Modeling Of Deformation (VMOD) Inversion Framework: Application to 20 Years of Observations at Westdahl Volcano and Fisher Caldera, Alaska, US

“…The framework also allows inversion using multiple data types at the same time with multiple inversion algorithms. Crozier et al (2023) showed a surprising dependency of model results on the chosen inversion methodology, which makes straightforward change or addition of inversion strategies an important feature of frameworks like VSM (Trasatti, 2022) and VMOD.…”

“…Although there are several inversion codes such as dModels (Battaglia et al., 2013a) or GBIS (Bagnardi & Hooper, 2017), incorporation of a new data type or a new model into a package can be difficult or even impossible in cases when we do not have access to a proprietary software license. And while some frameworks may be written in open source, high‐level programming languages and facilitate customization (e.g., Trasatti, 2022), VMOD provides well‐specified interfaces ( Source, Data, Inverse , Figure 1) that allow the addition of new models (e.g., Bonafede & Ferrari, 2009; Nishimura, 2009; Segall, 2010), straightforward combination of existing models for forward (e.g., regularized sill/faults and ring fault models) and inverse applications, or data sources by simply providing a new class that inherits from the respective base class, without having to alter the core VMOD code. The framework also allows inversion using multiple data types at the same time with multiple inversion algorithms.…”

“…Bagnardi and Hooper (2017) also provide MATLAB‐based code, the Geodetic Bayesian Inversion Software (GBIS), for InSAR and GNSS data analysis using the geodetic models from dModels and a Bayesian inversion approach using the Markov‐Chain Monte Carlo (Markov Chain Monte‐Carlo (MCMC)) method via the Metropolis‐Hastings algorithm (Hastings, 1970). Trasatti (2022) implemented a Python‐based code, the Volcanic and seismic source Modeling (VSM) that works with InSAR, GNSS, tilt, leveling and electronic distance measurement (EDM) data. This also supports inversions using multiple types of geodetic data and implements a global optimization algorithm and a Bayesian approach using the MCMC method.…”

Magma Transfer at Campi Flegrei Caldera (Italy) After the 1538 AD Eruption

“…We perform geodetic data inversions using the Python tool Volcanic and Seismic source Modeling (VSM, Trasatti, 2022). The modeling is aimed at retrieving information (location, depth, and volume variation) on the sources of the plumbing system active during the uplift and subsidence phases from 1515 to 1650.…”

“…The elevations at each site are available in the Supplementary Material. The VSM code (https://doi.org/10.5281/ zenodo.7950408) is published in Trasatti (2022) and available at https://github.com/EliTras/VSM. The inversions are carried out using Jupyter Notebooks.…”