DeFord Lecture Series
DeFord Lecture Series Speaker Schedule
The DeFord (Technical Sessions) lecture series has been a requirement and a tradition for all graduate students since the late 1940s. Once the official venue for disseminating Department of Earth and Planetary Sciences graduate student research, the DeFord Lecture series is now the forum for lectures by distinguished visitors and members of our community. Faculty and researchers from the Jackson School have invited prestigious researchers from around the world to present a lecture in this series. This is made possible only through a series of endowments, such as those funding past Distinguished Lectures.
The list below shows all the scheduled talks this semester. If you would like to meet with any of the speakers, please contact them or their hosts directly.
DeFord Lecture Series 2025 Speaker Schedule
All talks are Thursdays from 4-5 p.m. in the Boyd Auditorium (JGB 2.324). Lectures will be recorded, and most past lectures are posted on the Jackson School YouTube channel.
Jan. 30
Dr. Bayani Cardenas
Department of Earth and Planetary Sciences
Jackson School of Geosciences
University of Texas at Austin
Ridge to Reef Volcanic Hydrogeology: Submarine groundwater in the World’s Most Biodiverse Coasts
Abstract: Water flows from land to the ocean not only through rivers and estuaries but also below-ground through coastal and submarine aquifers. While the global fresh submarine groundwater discharge (SGD) is less than 1% of river discharge, it is quite relevant chemically as groundwater nutrient inputs are 25% of riverine inputs. This land-ocean connectivity is important for sensitive ecosystems such as coral reefs if the groundwater delivers solutes that are either critical for or harmful to reef life. Here, we present the interesting but potentially common situation of dramatic SGD in a volcanically active area in the Philippines which has been identified as the world’s most biodiverse coastal area and whose coral reefs provide for local communities.
We studied coastal and submarine thermal springs associated with high fluxes of acidic waters and carbon dioxide, some of which are within or close to thriving coral reefs. The SGD fluxes are amongst the largest in the world and the SGD carbon dioxide fluxes overwhelm coastal carbon budgets. The presentation delivers explanations for the high SGD, discussing the mechanics and different sources and pathways of water, by bringing together multiple lines of evidence from different methods including deep diving, drones, novel sensors, geochemical tracers, thermal remote sensing, and modeling.
Feb. 6
Dr. Peter DeCelles
University of Arizona
Why the Central Andes are Larger than the Himalaya
Abstract: The Central Andean and Himalayan orogenic belts provide an ideal natural experiment to test the potential role of climate in controlling orogeny. Approximately equal in age and along-strike length, both orogenic wedges are forming in plate-marginal convergent tectonic settings: The Andes in a retroarc setting and the Himalaya in a collisional setting against the Tibetan backstop. The Central Andes orogenic wedge is volumetrically and aerially nearly twice as large as the Himalayan orogenic wedge, despite the Himalaya having accommodated at least three times more tectonic shortening. The Himalaya exports at least four times more sediment owing to much greater erosion rates as signified by widespread Cenozoic metamorphic rocks and very young (<10 Ma) low-temperature thermochronologic ages. The Central Andes are thermochronologically old (mostly 20-100 Ma), have no exposures of Cenozoic metamorphic rocks, and are mantled by volcanic and sedimentary rocks, attesting to shallow, slow erosion. The most likely culprit for this situation is the greater intensity of the Indian Monsoon relative to the South American Monsoon since Oligocene time. When viewed as an orogenic wedge that has developed largely after formation of the Tibetan orogenic collage, the Himalaya is neither the largest nor hottest among Earth’s orogens.
Feb. 13
Dr. Yangkang Chen
Bureau of Economic Geology
Jackson School of Geosciences
University of Texas at Austin
AI for Seismology: How to Make it Work for Daily Operation and Better Science
Abstract: Artificial intelligence (AI) has witnessed enormous success in a variety of fields, especially in seismology. It has become widely accepted that deep learning (DL) techniques greatly help routine seismic monitoring by enabling more accurate P- and S-wave arrival picking than traditional methods. However, a completely automatic and in-production AI-driven earthquake monitoring framework has not been reported due to concerns about potential false positives using DL pickers. In this talk, I will introduce a novel AI-facilitated real-time earthquake monitoring framework developed from scratch over the past decade. The choice of optimal DL architecture is based on a decade-long iterative refinement of machine learning models and expansion of the training database. This AI system has been deployed in the Texas seismological network (TexNet) for daily operation. For the West Texas area, the seismic monitoring has been relying on our in-house DL model for reporting earthquakes to the public. For earthquakes with a magnitude above two, the picks are further validated by analysts to output the final TexNet catalog. Due to the fast-increasing seismicity caused by continuing oil & gas production in West Texas, this AI-facilitated framework significantly relieves the workload of TexNet analysts. On the other hand, AI techniques open the door to solving many scientific problems in an unprecedented way, including refining deep earth models with enhanced data preconditioning and iterative solvers, understanding the anthropogenic causes of induced earthquakes, and deciphering the earthquake nucleation mechanisms.
Feb. 20
Dr. Nicola Tisato
Department of Earth and Planetary Sciences
Jackson School of Geosciences
University of Texas at Austin
The Rock-Physics of Geo-Fluids
Abstract: The energy sector has long relied on subsurface exploration, with reservoir fluids playing a fundamental role in ensuring resources. Today, and likely in the future, exploiting the subsurface will be increasingly vital for advancing an energy landscape driven by emerging technologies that address the challenges of the climate crisis, such as geothermal, carbon capture utilization and sequestration (CCUS), and hydrogen storage. Therefore, enhancing our understanding of geologic processes by improving our geophysical toolkit is essential for implementing these innovations and boosting resilience. Here, I present scientific results that offer valuable insights for advancing subsurface imaging, monitoring, and exploration. I will showcase a combination of theoretical work with laboratory and numerical experiments investigating how multiphase fluids – e.g., CO₂ or hydrogen bubble-bearing brines – influence seismic wave propagation in reservoirs. I will also present novel rock physics experiments paired with micro-computed tomography (CT) imaging, revealing how the dissolution and precipitation of minerals in ultramafic rocks control their physical properties during carbon sequestration.
Feb. 27
Dr. Jean Philippe Avouac
California Institute of Technology
Advances in Earthquakes Forecasting
Abstract: Abundant and well documented examples of earthquakes induced by extracting or injecting fluids from the subsurface have provided an opportunity to investigate earthquake physics and test earthquake forecasting models. The presentation will show that spatial and temporal variations of seismicity rate can be predicted well based on stress changes informed by reservoir operations and surface deformation measurements. This modelling framework can be used to mitigate the risk of induced seismicity during CO2 storage of geothermal operations. These progress open avenues for time-dependent probabilistic forecasting of the time, location and magnitude of individual events.
March 6
Dr. Roger Creel
Department of Geology and Geophysics
Texas A&M University
Retreat, Regrowth, and Rapid Thinning: Reconstructing the Holocene History of the Antarctic Ice Sheet
Abstract: Understanding how the Antarctic Ice Sheet changed during past warm periods helps us project how fast Antarctica may shrink during the 21st century. The research I will present constrains Antarctic Ice Sheet change during the Holocene (11.7 – 0 thousand years ago), which is the last time global temperatures may have exceeded early Industrial (1850 CE) values. I will first estimate the Antarctic contribution to Holocene global mean sea level via a statistical framework that merges glacial isostatic adjustment models with observations of past sea level and nearfield Antarctic constraints. This estimate requires constructing the first quantitative estimates of Holocene mountain glacier volume and sea level change due to ocean thermal expansion, which I will discuss. I will then use cosmogenic nuclide exposure ages and marine sedimentary data to reconstruct how Antarctica thinned during the Holocene. I will close by comparing Antarctica’s Holocene history to modern and future trends to give perspective on the response of our largest ice sheet to warming.
March 13
Dr. Marjorie Cantine
College of Environment
Department of Earth and Space Sciences
University of Washington
Matters of Time: Controversy, Correlation, and the Dating of Sedimentary Records
Abstract: Time is a master variable in the Earth sciences, key to calculating rates and fluxes, drawing causal relationships between events, and determining the frequency of events. The importance of time motivates us to try and quantify it in sedimentary records of Earth’s changing life and environments. In this talk, I’ll discuss some of the geological and analytical challenges at the frontier of telling time in Earth’s complex surface environments and share the progress that my research group is making in dating the rise of animals on the Precambrian Earth.
March 27
Dr. Manuele Faccenda
Department of Geosciences
Università degli Studi di Padova, Padova, Italy
Central Mediterranean Structure and Dynamics From Combined Geodynamic and Seismological Modeling
Abstract: The Tertiary tectonic evolution of the Central Mediterranean and its first-order present-day structure have been relatively well constrained by abundant geological and geophysical data. Yet, several uncertainties persist about the mechanisms that led to the present-day surface morphology and deep slab geometry. With this respect, over the past few years new geodynamic and seismological modeling techniques have been combined to reproduce the recent large-scale evolution of the Central Mediterranean and provide mechanical constraints through the mapping of seismic anisotropy. The geodynamic simulations were designed and calibrated according to paleogeographic-tectonic reconstructions and seismological observations available in the literature. It is found that, although the opening of back-arc extensional basins in response to the retreat of the Ionian slab is a common feature in all models, structural heterogeneities within the Adria plate and/or the geometry of its Tyrrhenian passive margin profoundly impact on the segmentation of the subducting slab and the amount of Ionian trench retreat. This scenario is supported by anisotropic P-wave travel-time and S-wave splitting-intensity tomography models of the upper mantle covering the entire Mediterranean basin. The isotropic component of our preferred tomography model is dominated by numerous fast anomalies associated with retreating, stagnant, and detached slab segments. In contrast, relatively slower mantle structure is related to slab windows and the opening of back-arc basins. The anisotropy patterns are interpreted as the result of asthenospheric material flowing primarily horizontally around the main slabs in response to pressure exerted by their mid-to-late Cenozoic horizontal motion, while sub-vertical anisotropy possibly reflects asthenospheric entrainment by descending lithosphere.
The last part of the seminar is then dedicated to the discussion of a recent, stochastically-based, anisotropic tomographic model of the Etna volcanic field (Sicily, Italy), where a cylindrical pattern of P-wave slow axes is imaged in the 6-16 km depth range. According to the predictions of geodynamic modeling, this peculiar and unprecedently imaged structure should be primarily related to a radially distributed vertical dikes departing from a pressurized magma chamber.
April 3
Dr. Zhe Jia
University of Texas Institute for Geophysics
Jackson School of Geosciences
Earthquake Source Complexities: Insights on Rupture Dynamics and Hazard Mitigation
Abstract: Effectively assessing and reducing earthquake risks requires understanding why earthquakes can unfold in ways that standard seismic models often fail to predict. This talk explores how fault ruptures can be more complex than our usual assumptions suggest, making earthquake magnitudes and impacts especially hard to forecast. In this talk, I highlight some representative major earthquakes in recent years to illustrate the complexity of seismic ruptures. By integrating new modeling methods with multiple geophysical data and lenses, we can quantify their detailed rupture complexities, examine the compositional and thermal conditions of their source regions, and dynamically reproduce their faulting processes to uncover underlying physics and controlling factors. These advances provide insights into Earth’s multi-scale dynamics and highlight the value of unifying views from data-driven and physics-based models. By systematically exploring rupture complexities, we take steps toward closing the gap between theoretical and observational understanding of earthquake physics, thereby improving earthquake forecasts and hazard mitigation.
April 10
Dr. Mike Ek
Joint Numerical Testbed Program
National Center for Atmospheric Research
Land-Atmosphere Interactions: Will Clouds Form?
Abstract: Local land-atmosphere coupling involves the interactions between the land-surface and the atmospheric boundary layer (ABL), and in turn with the free atmosphere above. Initiation of fair-weather cumulus requires an increase in relative humidity at the ABL top, and depends on a number of processes, some opposing each other. Those processes include the evolution of surface fluxes, sub-surface heat and moisture transport, surface-layer turbulence, as well as boundary-layer development, and warm- and dry-air entrainment into the ABL from the free atmosphere above. Following an analytical development, we use modeling and observational data sets to examine this question.
April 17
Dr. Charlie Kerans
Department of Earth and Planetary Sciences
Jackson School of Geosciences
University of Texas at Austin
April 24
Dr. Karen McKinnon
University of California Los Angeles