About

Luc Lavier is a Professor at the UT Institute for Geophysics with research interests focused on the flow and deformation of Earth's materials, tectonics of plate boundaries, and computational methods for lithospheric deformation. His work involves understanding the physical processes that shape the Earth's crust and mantle, contributing to the broader field of geodynamics and tectonics. As a key member of the institute, he engages in advancing knowledge of Earth's structural behavior through computational modeling and analysis, supporting the institute's mission to understand the Earth and other planets.

Research topics

• Petrology
• Seismology
• Geology
• Materials science
• Geophysics
• Geotechnical engineering
• Geochemistry
• Composite material
• Geodesy
• Geometry
• Geomorphology

Selected publications

• High-resolution Coral Geodesy in the Solomon Islands

  2026-03-14

  articleOpen accessCorresponding

  The classical earthquake cycle is commonly described as alternating between long periods (decades to centuries) of interseismic locking and brief episodes (seconds) of coseismic rupture. However, increasingly dense geodetic observations from recent megathrust earthquakes reveal a more complex spectrum of transient deformation processes that challenge this binary framework. The New Georgia Group in the Solomon Islands provides a unique natural laboratory to investigate these processes, where the Woodlark Basin subducts beneath the Solomon Arc and has generated large megathrust earthquakes, including the 1936 Mw 7.9 and 2007 Mw 8.1 events.The close proximity of the islands to the trench allows Porites corals to serve as high-resolution recorders of vertical ground motion. While coral morphology has long been used to identify coseismic uplift, we introduce a novel approach that combines coral morphology with stable isotope analysis (δ¹³C and δ¹⁸O) to quantify relative sea-level (RSL) variations at annual resolution. We first assess the robustness of the relationship between coral water depth and δ¹³C using 141 new samples collected across a range of depths formed within the same time interval. For depths between 170 and 110 cm below sea level, δ¹³C exhibits a strong linear correlation with water depth (R² = 0.982), while shallower samples display a non-linear response.We then apply this RSL proxy to a 692-sample coral time series spanning 1928–2012 and validate the reconstructed RSL against available tide-gauge records. The 2007 Mw 8.1 earthquake is clearly resolved, with coral morphology recording ~70 cm of coseismic uplift expressed as a pronounced die-down surface, accompanied by a δ¹³C excursion exceeding 2‰. The 1936 Mw 7.9 event is similarly captured by a distinct δ¹⁸O anomaly, with postseismic relaxation observed consistently along two independent drilling transects.Beyond discrete coseismic signals, the record reveals multi-year to decadal periods of uplift and subsidence that we interpret as complex interseismic deformation. In particular, we identify intervals consistent with slow slip activity during 1955–1964, 1977–1986, and 1999–2002. These results demonstrate that stable isotope measurements in corals provide a powerful bridge between instrumental geodesy and paleoseismology, enabling a continuous, high-resolution view of subduction-zone deformation and stress evolution across the full earthquake cycle.

  PublisherDOI

• Magma-poor To Volcanic Margins: New Models

  2025-03-15

  preprintOpen access1st authorCorresponding

  We use a newly developed model formulation to explore the potential structural evolution of a spectrum of margins from Volcanic to Magma-poor. We assume that the melt is incompressible, and we simulate melt migration as magmatic intrusions and volcanic extrusions as volume change and stress change in the brittle and ductile crust. We also model heat transfer generated by melt migration, latent heat of recrystallization, melt production and hydrothermal circulation. Based on our simulation and observations of passive margins, we propose models for the formation of volcanic and magma-poor margins. While magma-poor margins evolution follows well-known stages, we show that volcanic margins represent a wide spectrum of behavior from purely accretionary and volcanic to mixed extensional and volcanic. The nature and extent of seaward dipping reflectors (SDRs), the crustal composition and structure, the subsidence of the margins vary as a function of the mantle potential temperature in the asthenosphere and the initial geothermal signature of the lithosphere.We can resume our main findings which diverge strongly from existing models for volcanic margins: (1) For mantle potential temperatures (Tp) greater than 1400oC, we find that volcanic margins form through the accretion of intrusive magmatic and extrusive volcanic product of melt production in the asthenosphere. This system forms an accretionary center of thickness and width increasing with Tp. On both side of the accretionary axis, two symmetrical SDRs basins form. Subsidence of these basins increase with decreasing Tp. Increasing subsidence generated by far field extension leads to an increase in clastic sedimentation and controls SDRs composition. Decreasing Tp and increased subsidence leads to the formation of clastic rich SDRs while increasing Tp and decreased subsidence leads to formation of mainly volcanic/mafic SDRs. (2) The exhaustion of melt production leads to ridge jumps and the formation of eccentric accretionary center. When subsidence is more pronounced for a lower Tp we simulate periods of uplift and subsidence correlated with periods of higher and subdued melt production, respectively. This process may result in cyclical periods of mafic followed by clastic sedimentation. (3) For Tp lower than 1400oC, intermediate margins form with both volcanic and extensional processes occurring concurrently. This processes eventually lead to the asymmetric propagation of volcanic centers which may lead to seafloor spreading.

  PublisherDOI

• Regionalized Formation and Recycling of New Venusian Crust at Chasmata

  The Planetary Science Journal · 2025-09-01

  articleOpen access

  Abstract Venus and Earth are geologically active in ways distinct from each other. Earth exhibits plate tectonics, where the primary resurfacing mechanism is crust formation along a globe-girdling, extensional tectonic setting in mafic crust, the mid-ocean ridge (MOR). While Venus does not exhibit the key characteristics of plate tectonics, it also possesses a globe-girdling, extensional tectonic setting in mafic crust referred to here as the global rift network (GRN). Despite the macroscale similarities, the two rift systems feature disparate characteristics. Using numerical modeling compared against topographic models from Magellan, we test whether seafloor-spreading-like tectonics under Venusian conditions can reproduce the morphology of individual chasmata along the GRN. The results indicate that the MOR-like seafloor spreading does not occur along most of the GRN, only in unique tectonic environments like that within Artemis Corona. On the other hand, we find that rift-embedded coronae along the GRN have morphologies best explained by excess crustal formation and subsequent densification leading to lithospheric delamination like ephemeral subduction postulated for coronae in previous studies. This suggests that secondary hot spots form between the major plumes under Beta, Atla, Themis, and Phoebe Regios. These minor plumes follow the flow of the upwelling mantle to initiate the formation of rift-embedded coronae along the GRN before becoming inactive when the hot spot dies. Such regionalized formation and recycling of the crust under the influence of mantle plumes is consistent with active geodynamics with limited plate mobility, such as predicted by plutonic-squishy lid, deformable lid, and globally fragmented lid tectonic hypotheses.

  PublisherDOI

• Decadal to Centennial Vertical Paleogeodetic Record of the Seismic Cycle in the Western Solomons from Coral Paleogeodesy and Stable Isotopes

  2025-03-15

  preprintOpen accessCorresponding

  The extremely shallow location of the seismogenic megathrust in the western Solomons and the existence of significant island land area on the upper plate overlying the seismogenic zone enables us to use corals to obtain vertical motion history closer to the trench and lower plate than anywhere else in the world. In addition, coral paleogeodesy on Porites microatolls acting as long-term vertical positioning station may provide a relative sea level (RSL) change record spanning hundreds of years. Our goal is to develop a centennial record of sea level change and vertical tectonics from multiple Porites microatolls. By isolating the RSL record common to each microatolls, we can then derive a vertical tectonic record by removing the RSL variations from the raw time series recorded by the microatolls.  To achieve that goal, we present recent work combining coral paleogedesy, annual δ13C record and modeling of coral morphology over the last 80 years in the western Solomons. The steps to obtain a long-term record of sea level change and vertical tectonics on samples of a ~80 year old Porites head collected in 2013 after the 2007 Mw 8.1 earthquake. We sampled the coral over 2 to 3 annual bands every ~2 months at various depths and times, performed a stable isotope analysis on each sample, cross-correlated each record and plotted the variation in δ13C versus water depth. Linear regressions show that the variation in accumulated δ13C as a function of water depth relative to the coral’s top water depth is 41 cm/‰ with a R2 coefficient of 0.98. We the sampled bimonthly stable isotopes along 80 annual bands. The span of each year is determined from correlating the annual banding and the seasonal cycles in δ13C and δ18O. Applying the linear relationship to the δ13C generates a raw record of relative sea level change. We then use the monthly tide gauge record in Honiara (Guadalcanal) to remove the effects of regional sea level change to the RSL time series obtain from the coral. The result is a record of the vertical tectonic motion of part of the Western Solomon before and after the Mw8.1 2007 earthquake. We analyze the results in terms of the yearly vertical record of the seismic cycle. Current geodetic records at subduction zones constrain at most deformation during one earthquake cycle while multiple earthquake cycles are needed to robustly constrain the physical state of a megathrust.  We hope to be able to extend the coral paleogeodetic record in the Weatern Solomons over several hundred years over multiple seismic cycles.  This would represent a critical data gap that hampers our understanding of subduction physics and our ability to forecast earthquakes.

  PublisherDOI

• Complex and confined laboratory ruptures explain scaling of the critical slip distance for earthquake faulting

  2024-08-22

  preprintOpen access

  Earthquake sequences in nature are complex, exhibiting a range of magnitudes and slip behaviors. In contrast, earthquake-like instabilities generated on frictional faults in the laboratory and in continuum numerical models are usually quasi-periodic with a smaller range of magnitudes and durations. The discrepancy, especially apparent for cm-sized samples used in lab friction experiments, has been attributed to complex multi-fault interactions in nature and heterogeneities in stress state or strength of seismogenic faults. Here, we provide another explanation by combining laboratory experiments and numerical models of fully deformable faults that show complex rupture sequences and fully confined slip events. We observe complex rupture sequences even on simple, initially homogeneous faults ranging from a few centimeters, in the lab, to tens of kilometers in numerical models. Our results show that self-generated heterogeneities on lab faults can produce slow and complex ruptures that may be fully confined on mm-scale faults, challenging the long-held idea that such lab faults fail only as rigid blocks. We also document complex behaviors including aperiodicity and significant variability in rupture properties over short timescales due to local, self-generated heterogeneities in stress and friction strength. Our simulations show that the ratio of fault zone thickness to the critical slip distance, Dc, controls the observed failure mode, with wider shear zones and larger Dc giving rise to slower slip events. We demonstrate (a) that complex rupture behaviors can arise even on initially homogeneous faults, and (b) that the same fault may accommodate a spectrum of earthquake slip modes at different scales.

  PublisherOA PDFDOI

• Mantle Deformation Processes during the Rift-to-Drift Transition at Magma-Poor Margins

  2023-03-28

  preprintOpen access

  The rift-to-drift transition at rifted margins is an area of active investigation due to unresolved issues of the ocean-continent transition (OCT). Deep structures that characterize modern OCTs are often difficult to identify by seismic observations, while terrestrial exposures are preserved in fragments separated by tectonic discontinuities. Numerical modeling is a powerful method for contextualizing observations within rifted margin evolution. In this article, we synthesize geological observations from fossil ocean-continent transitions preserved in ophiolites, a recent seismic experiment on the Ivorian Margin of West Africa, and GeoFLAC models to characterize mantle deformation and melt production for magma-poor margins. Across varied surface heat fluxes, mantle potential temperatures, and extension rates our model results show important homologies with geological observations. We propose that the development of large shear zones in the mantle, melt infiltration, grain size reduction, and anastomosing detachment faults control the structure of OCTs. We also infer through changes in fault orientation that upwelling, melt-rich asthenosphere is an important control on the local stress environment. During the exhumation phase of rifting, continentward-dipping shear zones couple with seaward-dipping detachment faults to exhume the subcontinental and formerly asthenospheric mantle. The mantle forms into core-complex-like domes of peridotite at or near the surface. The faults that exhume these peridotite bodies are largely anastomosing and exhibit magmatic accretion in their footwalls. A combination of magmatic accretion and volcanic activity derived from the shallow melt region constructs the oceanic lithosphere in the footwalls of the out-of-sequence, continentward-dipping detachment faults in the oceanic crust and subcontinental mantle.

  PublisherOA PDFDOI

• Mantle Deformation Processes during the Rift-to-Drift Transition at Magma-Poor Margins

  2023-02-27

  preprint

  The rift-to-drift transition at rifted margins is an area of active investigation due to unresolved issues of the ocean-continent transition (OCT). Deep structures that characterize modern OCTs are often difficult to identify by seismic observations, while terrestrial exposures are preserved in fragments separated by tectonic discontinuities. Numerical modeling is a powerful method for contextualizing observations within rifted margin evolution. In this article, we synthesize geological observations from fossil ocean-continent transitions preserved in ophiolites, a recent seismic experiment on the Ivorian Margin of West Africa, and GeoFLAC models to characterize mantle deformation and melt production for magma-poor margins. Across varied surface heat fluxes, mantle potential temperatures, and extension rates our model results show important homologies with geological observations. We propose that the development of large shear zones in the mantle, melt infiltration, grain size reduction, and anastomosing detachment faults control the structure of OCTs. We also infer through changes in fault orientation that upwelling, melt-rich asthenosphere is an important control on the local stress environment. During the exhumation phase of rifting, continentward-dipping shear zones couple with seaward-dipping detachment faults to exhume the subcontinental and formerly asthenospheric mantle. The mantle forms into core-complex-like domes of peridotite at or near the surface. The faults that exhume these peridotite bodies are largely anastomosing and exhibit magmatic accretion in their footwalls. A combination of magmatic accretion and volcanic activity derived from the shallow melt region constructs the oceanic lithosphere in the footwalls of the out-of-sequence, continentward-dipping detachment faults in the oceanic crust and subcontinental mantle.

  PublisherDOI

• Constraining Fault Damage Zone Properties From Geodesy: A Case Study Near the 2019 Ridgecrest Earthquake Sequence

  Geophysical Research Letters · 2023-02-28 · 10 citations

  articleOpen accessSenior author

  Abstract Seismologic studies have reported seismic velocities reduction and V p / V s ratio changes over damage zones associated with seismogenic faults. The structure and elastic properties of these damage zones indicate the maturity of faults and affect the rupture dynamics of future seismic events. Therefore, they contain critical information about fault properties that could inform seismic hazards. Here we present a geodetic modeling approach to constrain velocity changes and elastic properties of fault damage zones under stress perturbation from nearby earthquakes. Compared to seismic tomographic analysis that is usually limited by resolution, this geodetic approach provides tighter constraints on the elastic properties and geometry of the damage zone at shallow depths. Our results imply that a major component of the shallow strain release is distributed and inelastic. The existence of numerous shallow faults either may indicate a locally detached shallow layer or they are remnants from earlier fault evolution.

  PublisherOA PDFDOI

• Mantle Deformation Processes During the Rift‐To‐Drift Transition at Magma‐Poor Margins

  Geochemistry Geophysics Geosystems · 2023-11-01 · 5 citations

  articleOpen access

  Abstract The rift‐to‐drift transition at rifted margins is an area of active investigation due to an incomplete understanding of the spatial and temporal evolution of physical and chemical processes at the ocean‐continent transition (OCT). Deep structures that characterize modern OCTs are often difficult to identify by seismic observations, while terrestrial exposures are preserved in fragments separated by tectonic discontinuities. Numerical modeling is a powerful method for contextualizing physical processes and observations relevant to rifted margin evolution. We synthesize results from geological observations of fossil OCTs preserved in ophiolites, a recent seismic experiment on the Ivorian margin, and numerical modeling to characterize mantle deformation and melt production for magma‐poor margins. Across varied surface heat fluxes, mantle potential temperatures, and extension rates, our model results show homologies with geological observations. We propose that the development of large shear zones in the mantle, melt infiltration, grain size reduction, and anastomosing detachment faults control the structure of OCTs. We also infer that a hot, upwelling, melt‐rich asthenosphere is an important control on the local stress environment. During the exhumation phase, continentward‐dipping shear zones couple with seaward‐dipping detachment faults to exhume the subcontinental and formerly asthenospheric mantle. The mantle forms core‐complex‐like domes of peridotite at or near the surface. The faults that exhume these peridotite bodies are largely anastomosing and exhibit magmatic accretion in their footwalls. A combination of magmatic accretion and volcanic activity derived from the shallow melt region constructs the oceanic lithosphere in the footwalls of the out‐of‐sequence continentward‐dipping detachment faults in the oceanic crust and subcontinental mantle.

  PublisherOA PDFDOI

• Characterizing mantle deformation processes during the rift-to-drift transition at magma-poor margins

  2022-03-28

  preprintOpen accessCorresponding

  <p>A holistic understanding of rift initiation, evolution, and variation is made complicated by the difficulties of deep seismic imaging, limited modern examples of continental rifting, and few accessible outcrops of fossil rifted margins. In particular, <strong>The temporal structural</strong> and rheological evolution of the mantle lithosphere during rifting<strong>is poorly constrained</strong>. The mantle lithosphere rheology controls lithospheric strength at initiation, <strong>but</strong> how deformation is partitioned between the crust and mantle,  and <strong>how</strong> the paths for melt migration from the asthenosphere to the rift surface <strong>evolve during rifting is fundamental for our understanding of the rift-to-drift evolution </strong>.<br>Here, we use elastoplastic-viscoelastoplastic modeling in concert with published deep seismic profiles of Atlantic rifted margins and geological insights from the Lanzo peridotite outcrops in the Alps to propose a new mode of extensional tectonics in the subcontinental mantle. We run a series of dynamic models varying initial conditions and mechanisms of deformation localization in the mantle lithosphere consistent with mechanisms of ductile shear <strong>zone</strong> formation observed at slow spreading centers. Models and geophysical surveys show homologous, sigmoidal reflectors in <strong>the</strong> mantle, a reversal of fault vergence as seafloor spreading develops, exhumation of the mantle, and increasing magmatic accretion. Geological evidence, along with the coincidence of magmatic accretion and extensional structures in the mantle, suggests that faults in the mantle may serve as conduits for melt, resulting in bright reflectors <strong>on seismic profiles</strong>.</p>

  PublisherDOI

Recent grants

• Collaborative Research: Experimental analysis of strain transients in a heterogeneous semi-brittle system: Implications for tectonics

  NSF · $67k · 2016–2019

• Collaborative research: Uplift and faulting at the transition from subduction to collision - a field and modeling study of the Calabrian Arc

  NSF · $291k · 2006–2011

Frequent coauthors

• Giänreto Manatschal

  43 shared

• K. D. McIntosh

  The University of Texas at Austin

  38 shared

• Harm J. A. Van Avendonk

  The University of Texas at Austin

  31 shared

• Suzon Jammes

  Texas State University

  30 shared

• W. Roger Buck

  Lamont-Doherty Earth Observatory

  27 shared

• Mathilde Cannat

  Institut de physique du globe de Paris

  23 shared

• Eunseo Choi

  22 shared

• Nicholas W. Hayman

  22 shared