Geodesy is an important tool for exploring the geometry and temporal evolution of magma plumbing systems, as well as for monitoring and hazards assessment during volcanic unrest and eruption. Geodetic techniques include measurements of both deformation (to determine the magnitude, location, and geometry of subsurface sources of pressure change) and gravity (to assess subsurface mass variations). This IAVCEI Commission on Volcano Geodesy helps organize the diverse community and promote a better understanding of magmatic processes through geodesy.
During the AGU Meeting we had a Volcano Geodesy meetup (in two parts to accommodate so many time zones!). Thank you for joining, if you were able, and here we provide notes in case you were not able. It was attended by 25 members from at least 6 time zones!
We started by discussing about how to replace the planned Volcano Geodesy meeting that had been scheduled for October 2020 and was cancelled by covid. There seemed to be an interest of going ahead with some kind of virtual meeting or exercise, with the hope that we would be able to have an in-person meeting next year or, at least, as soon as the pandemic conditions will re-allow travelling.
Modeling exercise:
The general consensus was that a modeling exercise would be useful for the community, for testing and understanding the differences among the different approaches. It would be best to start simple (likely synthetic model) and add complexity (moving to a real data set) as we work out the mechanics of arranging an exercise. Some important considerations that were brought up include:
- Making sure we are clear about the assumptions going into the model, and start simply
- It would be good to discuss the results in person, but since we don't know when that will be possible, we might be able to start virtually with the simple model.
- There are some existing synthetic data sets available, and it might be good to make a step-wise approach to starting very simply, and then expanding the scope of complexity.
There have been other exercises for similar collaboration and communication. If you have examples please share, but for one, here is a link to the results of the Southern California Earthquake Center transient detection exercise: https://pubs.geoscienceworld.org/ssa/srl/article-abstract/84/3/419/143995/The-SCEC-Geodetic-Transient-Detection-Validation?redirectedFrom=fulltext
We plan, with some volunteers (some volunteered during the meetup, but we are happy for more if you contact us!), to begin organizing a simple, virtual modeling exercise. We can present and discuss results virtually, with the future goal of having a more complex modeling exercise and in-person discussion.
Alex and I also brought up that because we do not have official bylaws yet, the terms for co-chairs are not explicit, but was casually thought to be 2 years. We are happy to stay on until we are through the pandemic, but please let us (or another messenger) know if you want to volunteer or nominate someone for one of the chair positions.
Also, we thank Marco Bagnardi for his service as Secretary, but since he has moved on to a different field, we are again looking for a Commission Secretary to help with the website. The website crashed and have just been rebuild with its essential structure (https://volcgeodesy.iavceivolcano.org). Now, it needs to be re-populated with news and everything interesting for our community. It could be a good platform for advertising our activities, papers, sessions and everything else, to be further promoted on our social accounts (facebook and twitter). Especially in this covid-conditioned period, web and social pages can play an important role. It is not a big job if everybody keeps in mind to exploit this opportunity, cooperating in producing interesting contents, and if you, and/or a student are interested in helping managing it!
Thank you to those of you who contributed descriptions of your work for the annual highlights reports. We are always interested in new work to highlight, if you publish something yourself, or see something in-print that would be worthy of a highlight.
A new reference publication of interest to Volcano Geodesy
An introduction to several monitoring techniques used in volcano geodesy was published by authors from multiple worldwide volcano observatories who are actively involved in monitoring volcanic unrest. The described methods include EDM, tilt, GPS, InSAR, microgravity and mathematical modelling, and the publication is intended as a reference.
Battaglia, Maurizio; Alpala, Jorge A.; Alpala, Rosa L.; Angarita, Mario; Arcos, Dario; Euillades, Leonardo; Euillades, Pablo; Muller, Cyril; Medina, Lourdes Narváez (2020). Monitoring Volcanic Deformation. Encyclopedia of Geology, 2nd edition, Elsevier.
Responding to volcano crises during Covid
In March 2020, the coronavirus disease 2019 outbreak was declared a pandemic by the World Health Organization and became a global health crisis. Authorities worldwide implemented lockdowns to restrict travel and social exchanges in a global effort to counter the pandemic. In France, and in French overseas departments, the lockdown was effective from 17 March to 11 May 2020. It was in this context that the 2–6 April 2020 eruption of Piton de la Fournaise (La Réunion Island, Indian Ocean) took place. The density and reliability of the OVPF networks, combined with satellite observations, allowed for trustworthy instrument-based monitoring of the eruption and continuity of the OVPF duties in issuing regular updates of volcanic activity in the context of a double crisis: volcanic and health.
Peltier, A., V. Ferrazzini, A. Di Muro, P. Kowalski, N. Villeneuve, N. Richter, O. Chevrel, J. L. Froger, A. Hrysiewicz, M. Gouhier, et al. (2020). Volcano Crisis Management at Piton de la Fournaise (La Réunion) during the COVID-19 Lockdown, Seismol. Res. Lett., 1–15, doi: 10.1785/0220200212.
Dynamics of deformation and satellite thermal infrared at Domuyo volcano, Argentina
The a present a decade-plus analysis that integrates, for the first time, time series of satellite interferometric synthetic aperture radar (InSAR) surface deformation and satellite thermal infrared edifice-scale surface warming at a large silicic system: Domuyo volcano, in Argentina. We find that deformation and warming are highly correlated, and depending on the sign and lag between the time series, either shallow sealing or magma influx could drive Domuyo’s ongoing inflation (~ 0.15 m/year; from an InSAR-derived tabular source, ~ 11 × 8 × 1 km; ~ 6.5 km depth; ~ 0.037 km3/year volume change rate) and warming (0.3–0.4 °C/year). This study shows the potential that combined satellite surface deformation and edifice-scale surface warming time series have on assessing the physical mechanisms of silicic volcanic systems and for constraining deterministic models.
Lundgren, P., T. Girona, M. G. Bato, V. Realmuto, S. Samsonov, C. Cardona, L. Franco, E. Gurrola, and M. Aivazis (2020), The dynamics of large silicic systems from satellite remote sensing observations: the intriguing case of Domuyo volcano, Argentina, Scientific Reports, 10, 11642.
Unsupervised modeling of volcano plumbing with GNSS
We propose a fully unsupervised Bayesian inversion method that uses the point compound dislocation model as a complex source of deformation, to dynamically identify the substructures activated during magma migration. We applied this method at Piton de la Fournaise, using Global Navigation Satellite System data preceding the June 2014 eruption. Obtained source shapes (dikes, prolate ellipsoids, or pipes) show magma migration from 7–8 km depth to the surface, drawing a mechanical “tomography” of the magma pathway. We implemented this method operationally as an extension of the GNSS module in the WebObs system (https://github.com/IPGP/webobs; Beauducel et al., 2020), an integrated web-based system for data monitoring and network management implemented in 15 observatories worldwide. This has been especially useful during the last eruption at Piton de la Fournaise (Peltier et al., 2020, see below).
Beauducel, F., Peltier, A., Villie, A., & Suryanto, W. (2020). Mechanical imaging of a volcano plumbing system from GNSS unsupervised modeling. Geophysical Research Letters, 47, e2020GL089419. https://doi.org/10.1029/2020GL089419
Deformation at Sabancaya Volcano
Sabancaya is the most active volcano of the Ampato-Sabancaya Volcanic Complex (ASVC) in southern Perú and has been erupting since 2016. The analysis of ascending and descending Sentinel-1 orbits (DInSAR) and Global Navigation Satellite System (GNSS) datasets from 2014 to 2019 imaged a radially symmetric inflating area, uplifting at a rate of 35 to 50 mm/yr and centered 5 km north of Sabancaya.
Boixart, G., Cruz, L. F., Miranda Cruz, R., Euillades, P. A., Euillades, L. D., & Battaglia, M. (2020). Source Model for Sabancaya Volcano Constrained by DInSAR and GNSS Surface Deformation Observation. Remote Sensing, 12(11), 1852.
InSAR measurements at Cordon Caulle
Here is a review of InSAR at Cordon Caulle. It is a summary of 17 years of InSAR applied to ground deformation and topography changes observation.
F. Delgado, Rhyolitic volcano dynamics in the Southern Andes: Contributions from 17 years of InSAR observations at Cordón Caulle volcano from 2003 to 2020, Journal of South American Earth Sciences, Volume 106, 2021, 102841, ISSN 0895-9811, https://doi.org/10.1016/j.jsames.2020.102841.
IAVCE is piloting an eVolcano video project to curate and distribute Volcanology videos. Please consider contributing some content!
The eVolcano pilot project includes peer-reviewed videos that are 20-30min long scientific lectures covering different fields and subjects in Volcanology, targeting the University level in English language. You could think of it like as many of you had to teach lately, i.e. by recording power point or zoom lectures. Of course, if anyone would be interested in using their Universities’ MOOC equipment they are encouraged to do so, but it is not mandatory. Please let the commission chairs know if you are interested in participating. We have one contribution already to discuss offshore geodesy, but some contributions relating general aspects of deformation monitoring methods would be a nice addition.