Dec 7, 2024
Building an International Community to Study Subduction Zone Geohazards
SZNet, the international collaboration component of SZ4D, is gearing up for its second year of activities beginning with an international workshop and field trip in January.
An in-person workshop focusing on Ocean Floor Observational Technology
SZNet is welcoming over 90 scientists and researchers to the Ocean Floor Observational Technology Workshop in January in Santiago, Chile. In collaboration with the Science of Slow to Fast Earthquakes Networks, we have planned a week of events including two international webinars and day-long field trips. These events are aimed at fostering collaboration and in depth discussions between researchers of different disciplines and backgrounds surrounding subduction zone science. Learn more about the Ocean Floor Observational Technology Workshop and the other events on the SZ4D Website.
Chile Field Trip
A team of 16 scientists will be leaving for SZNet’s second international field trip immediately following this workshop. During this 10-day excursion, participants will receive a comprehensive introduction to Chilean geology, beginning in the volcanic cordillera and making stops in Chile's central valley and coastal regions exploring stratigraphic exposures and landforms. These participants were selected after a rigorous application process from a pool of 142 applicants, and represent a wide variety of backgrounds, career stages, research interests, and nationalities. You will be able to learn more about them in the coming weeks on the SZNet 2025 Chile Field Trip webpage.
Meet the 2025 Chile Field Trip Cohort
From left to right, top to bottom:
Alexandra Daniels | Boise State University
Grant Long | Stanford University
Chelsea Mackaman-Lofland | University of Tennessee, Knoxville
Ian Wynn | University of Hawai'i at Manoa
Diana Roman | Carnegie Science
Ignacio Sepulveda | San Diego State University
Jeremias Likerman | UBA-CONICET
Maria Pia Rodriguez | Universidad Andrés Bello
Mariano Agusto | Universidad de Buenos Aires
Pamela Paz Jara | Universidad de Santiago de Chile and the Sociedad Geológica de Chile
Sofía Belén Iannelli | Instituto de Estudios Andinos (University of Buenos Aires - National Council on Scientific and Technical Research)
Tomas Capaldi | University of California San Diego - Scripps Institution of Oceanography
Jonathan Delph | Purdue University
Sarah Jaye Oliva | Universidad de Chile
Morgan Adamson | University of California, Santa Barbara
Mauricio Espinoza | Universidad de Concepción
2024 US & Chile Exchange Program
Meet the participants of our first edition of the US & Chile Exchange Program! Applications for the second edition are now closed. We will announce the third edition soon.. stay tuned!
Meet Javier Ojeda Vargas
About Javier's research project
Javier’s research project aimed to analyze the transient aseismic deformation along the Chilean margin and explore its links to seismic signatures such as swarm episodes and the nucleation of large earthquakes during the last decades. For this purpose, he explores novel methodologies to exploit geodetic time series, especially those from GPS data. His project has benefited from geodetic and seismological analysis, enabling him to leverage diverse datasets for new insights into transient deformation processes and, especially, slow slip events.
During his stay in the US, Javier collaborates with Dr. Roland Bürgmann, professor and leader of the Active Tectonics group at UC Berkeley. Through his time at UC Berkeley, Javier built strong connections with leading researchers and graduate students in the field, laying the groundwork for future collaborative research.
He was able to quantify the contributions of seismic and aseismic moment rates along the subduction interface in Chile, results that improve our understanding of the physical mechanisms driving these transient processes but also reflect the inherent need for ocean floor geodesy developments along the Chilean coast to further explore these signatures in the near future and better understand their potential implications for seismic hazard assessments.
This project is part of Javier’s broader vision to enhance the integration of geodetic and seismological observations in earthquake research, particularly applied to his homeland and unique natural laboratory with the observation of overlapping slip processes revealing the dynamical behavior of the Chilean subduction.
Although we have made important improvements during this one-month stay, we believe that we set the floor for publishing this work in the near future. For now, our next step will be a presentation at the next Slow-to-Fast Earthquake workshop in Santiago, Chile, organized by the Science of Slow to Fast Earthquakes Network (Japan), which is also held in cooperation with SZNet.
About Javier
I’m a Chilean geophysicist born in the southern city of Puerto Montt. I hold a PhD in Earth Sciences from the Universidad de Chile and the Institut de Physique du Globe de Paris, as well as a Master's degree in Geophysics from the Universidad de Chile. My research interests include a wide range of earthquake seismology and geodesy research, especially studying slip processes along subduction zones. Stay tuned to my current and past investigations at my research site.
I heard about the program thanks to social media and email updates from the SZ4D network. As well as my advisor's recommendation, who always encourages me to apply for different opportunities opened for early career scientists, especially this kind of grants that help us to discover new earth sciences departments and interact with outstanding researchers. Since my first short visit to Berkeley, I have been impressed by the work environment and great people working in the EPS and BSL, and I took the opportunity to come back in October to continue these collaborative efforts. This exchange certainly opened a lot of doors for me, including new opportunities to collaborate with peers and to understand how US-based researchers develop their science and share thoughts about the development subduction zone sciences.
Meet Leoncio Cabrera
About Leoncio's research project
The main goal of my exchange was to study the interaction between earthquake and volcanic processes at the Chilean subduction margin, in collaboration with William Frank at the Massachusetts Institute of Technology (MIT). We primarily worked with a large volume of seismic data and explored the use of optical and radar images, thanks to additional collaborations with other MIT researchers and students specializing in remote sensing.
Our results show very interesting things. We built a high-resolution seismic catalog, allowing us to track different processes in detail. We are still working on the interpretation, so I don't want to get ahead of that, but the plan is to put it all together in a scientific publication, where all our findings will be presented.
Beyond the research conducted during my 3.5-week stay at MIT, one of the most remarkable aspects for me was the extensive interaction I had with other researchers. William’s team welcomed me warmly and made me feel like a part of their group. Additionally, I had the opportunity to engage with many other people from MIT and visiting researchers. Working in such a stimulating environment was incredibly inspiring, and the earthquake science team at MIT is undoubtedly one of those places.
About Leoncio
I am originally from a small town in south-central Chile called Mulchén. I mention it because Mulchén is very close to the epicenter of the Mw 8.8 2010 Maule earthquake. I was still in high school at that time, but somehow it marked my path to become a seismologist. After several years studying and traveling, I am currently an assistant professor at the Pontificia Universidad Católica de Chile (UC Chile). As an anecdote, I started as a faculty almost at the same time I did my exchange at MIT. My main reason for applying for the exchange was to strengthen international collaboration between Chile and the United States and between our respective institutions, and to have the opportunity to work side by side with William and his group. For the near future, in January we have two events in Chile (the Slow to Fast Earthquake Workshop and the Ocean Technology Workshop, plus some field trips), so this time it will be William who will be in Chile. I am sure we will be able to continue collaborating in the future.
Meet Flavia Rojas Guzman
About Flavia's research project
In the Southern Andean volcanic arc, volcanic chains are related to different structural domains controlled by the plate boundary scale stress field (Lara et al., 2006). Observations show that these volcanic systems are spatially and genetically related to fault intersections (areas where faults cross) rather than disconnected subsidiary faults within a given system (e.g. Veloso et al., 2020). Areas of fracture intersection have been associated with increased fluid permeability up to two orders of magnitude compared to a single fracture (Stanton-Yonge et al., 2023), which may offer a possible interpretation of how and why volcanoes are spatially related to fault intersections. One fundamental unresolved issue is why some intersecting fault systems are associated with these systems and many others do not show an apparent correlation between enhanced fluid flow within the same arc system. This suggests that there are likely other first-order influence controls. For example, punctuated local variation in the stress state close to volumes of rock within or surrounding fault zone intersections. In this project, we propose to address the question: What is the role of fault intersections on local stress state variations at different scales? For this, we are studying the Puyehue-Cordón Caulle and Nevados de Chillan active Andean volcanic complexes as they offer unique exposure to the problem identified. During my 3-week visit to The Ohio State University, Dr Ashley Griffith introduced the theoretical basis and applications of the 3D Boundary Element Methods (BEM), which is particularly effective in simulating mechanical interaction between geometrically complex faults like our study case (Crider and Pollard, 1998; Griffith and Cooke, 2004; Muller et al., 2005; Stanton-Yonge et al., 2016). We designed our approach to the study cases and now we continue working and collaborating with the research team on our research question.
For our first case study, the Puyehue-Cordón Caulle Volcanic Complex (PCCVC), we have already collected over 200 structural measurements of faults in the field, from seven outcrops at different distances from the fault intersections. From this data, we performed stress inversions using the Multiple Inverse Method (MIM) and strain inversions using Faultkin. We are currently analysing and comparing the inversions of the different zones based on their relationship with the fault intersections. One of our findings until now is that in the Cochamó structural site, located close to an intersection between the Liquine-Ofqui fault system and an E-W lineament, there is more than one stress state solution. Fig. 1 shows the stress and strain inversions for Cochamó structural site. The MIM solution (upper plots) represents the orientation of the principal stress axes derived from the heterogeneous fault-slip data set by generating a combinatorial number of groups extracted from the whole data set (Yamaji et al., 2005, Perez-Flores et al., 2016). The orientations of the calculated stress axes for each generated group are plotted onto separate stereograms (σ1 and σ3) and represented as a tadpole coloured according to the calculated stress ratio (φ = (σ2 − σ3)/(σ1 − σ3)), thus groups of tadpoles with similar colours and similar orientations indicate a compatible stress field solution (Perez-Flores et al., 2016). In this case, we can observe the first blue-coloured group that represents a solution with a vertical σ1 and a semi-circle distributed σ3, this distribution is because σ3 is very similar to σ2, which is associated with an extension in all directions that might be occurring due to the intersection of these structures. We can also observe a second solution in the yellowish-coloured group, with a horizontal σ3 and distributed σ1, representing a different stress state recorded in the same place. Further analysis will be done to make progress on our understanding of the influence of these stress variations due to fault intersections in geofluid migrations in the crust. We plan to submit this work during the following year.
For our second case study, the Nevados de Chillán Volcanic Complex, we submitted a paper to the Journal of Volcanology and Geothermal Research (Espinosa-Leal et al., part of Espinosa-Leal PhD project) which was recently accepted for publication. This work is entitled “Fault intersection-related stress rotation controls magma emplacement at the Nevados de Chillán Volcanic Complex” and recompiles data of tens of dykes and thousands of fractures from representative outcrops around the complex. We use these data to generate a conceptual model of the response of the different fracture sets to regional and the potential consequences in terms of magma emplacement (Fig. 2). We propose that N-S to NW-SE striking fractures become reactivated by fault intersection-related local stress field rotations. This favours NW-SE aligned magma emplacement, and the evolution of NW-SE aligned volcanoes.
Now, we continue working from a modelling approach using BEM. This will allow us to study the fault intersection behaviour under tectonically realistic stress boundary conditions imposed by plate interaction at the subduction margin in different stages of the subduction seismic cycle. We plan to submit this work during the following year.
About Flavia
My name is Flavia Rojas Guzmán, I am from Chile, and I am currently doing a PhD in Volcanology at The University of Manchester. I applied to the first version of the SZ4D exchange program while working as a research assistant in the FONDECYT project previously described (1210591). One of the researchers of the project told me about this great opportunity, which was perfectly adapted to my work plans and the development of the project. To complement the training I received during my Master’s and Engineering degree, and to fulfil the goals of the project, I required training on methods that allow us to perform stress and strain inversions of the structural field data (fractures, fault kinematics, etc) and to model the different state of stress responses. To do this, I proposed to work with an expert in the field of boundary element modelling, Dr. Ashley Griffith. I decided to apply for this exchange because I strongly believe that international collaboration is key in scientific research, as it allows us to interact with experts on different topics, improve the quality of our work and address problems in more efficient ways by learning from the experiences of other research groups. It also contributes to creating networks of scientists with different access to resources, knowledge, and ideas, which allows us to produce better results and move forward more creatively in answering our scientific questions. This experience was an extraordinary opportunity to be part of a global scientific environment and learn a new tool that is allowing us to better understand and address our research problem. It also provided me with perspective from different points of view which contributes to becoming a more rounded professional.