About

Tiziana Vanorio is an Associate Professor in the Earth and Planetary Sciences Department at Stanford University, where she is also a Senior Fellow at the Precourt Institute for Energy and, by courtesy, of Civil and Environmental Engineering. She leads the Rock Physics and Geomaterials Laboratory, focusing her research on integrating laboratory experiments with analytical techniques to investigate the physical and mechanical properties of rocks and geomaterials. Her work explores the influence of composite structures on properties across various scales, from microstructural features to bulk properties. Her research program applies this understanding to study new processes for engineering the subsurface and materials, including enhancing CO2 reuse through accelerated mineralization techniques, studying the main engine of naturally occurring hydrogen, and replicating natural cementation processes and fibrous nanostructures. These efforts aim to improve resource efficiency, advance energy sustainability, and promote a more sustainable cement industry.

Research topics

• Geology
• Materials science
• Mineralogy
• Composite material
• Optics
• Mechanics
• Mathematics
• Geophysics
• Mathematical analysis
• Thermodynamics
• Petrology
• Geometry
• Chemical engineering
• Physics

Selected publications

• 3D Structure and Dynamics of Campi Flegrei Enhance Multi-Hazard Assessment

  2025-03-14 · 1 citations

  preprintOpen accessCorresponding

  Campi Flegrei is an active caldera in a densely populated area, currently experiencing significant ground uplift and seismicity. Leveraging precise relocations of extensive seismicity since 2014, we determined high resolution (250 m), 3D P- and S-wave seismic images of the inner caldera which we combine with a novel rock-physics experiment to characterize the primary features of the caldera’s 3D structure: a gas-rich reservoir below 2 km depth, a deformed caprock at 1 to 2 km depth, and a funnel-shaped, (thermo-metamorphic) basement below 3.5 km depth. Seismicity migrates downwards from the caprock to the reservoir, and, following reservoir depletion, stress loading triggers deeper, larger magnitude events along the inner-caldera boundary faults. The reservoir extent and the seismicity distribution closely correlate with the area of maximum uplift, where accelerating deformation due to pore-fluid pressure is corroborated by laboratory experiments using site-relevantin-situ rock samples. These findings suggest that coupling between gas-reservoir pressure and the fibrous microstructure of the confining caprock drives the ground uplift. This structural-dynamic reconstruction of interconnected seismic and ground deformation processes provides a framework for forecasting the evolution of unrest, which is crucial for enhancing medium- and short-term multi-hazard assessment and mitigation strategies. Our results indicate that seismic activity and the potential for a phreatic explosion should be considered as plausible scenarios, prompting a reevaluation of the hazard assessment for the area.

  PublisherDOI

• The recurrence of geophysical manifestations at the Campi Flegrei caldera

  Science Advances · 2025-05-02 · 11 citations

  articleOpen access1st authorCorresponding

  The Campi Flegrei caldera (CFc), Italy, exhibits distinct unrest patterns, including shallow seismicity following substantial strain accumulation, all within a densely populated area. Previous geophysical studies typically analyzed individual episodes, but by comparing two distinct unrest periods we identified recurring manifestations and V P / V S anomalies linked to a confined reservoir at 2- to 4-kilometer depth. Integrating rock physics experiments under hydrothermal conditions, 24 years of rainfall data, and subsurface hydrodynamics, we found increasing rainfall rates, which indicate reservoir recharge and pressurization. We show that hydrothermal water promotes caprock sealing through the formation of a fibrous microstructure. Our experiments further demonstrate that fluid accumulation rates directly influence deformation rates. Together, these processes drive gradual deformation, natural seismicity, and deepening earthquake foci. Recognizing these recurring patterns is crucial for understanding the caldera’s unrest-driving mechanism, enabling us to offer actionable insights for hazard assessment and engineering solutions, such as intercepting water upstream to prevent drainage toward Pozzuoli.

  PublisherDOI

• Author Correction: 3D structure and dynamics of Campi Flegrei enhance multi-hazard assessment

  Nature Communications · 2025-07-03

  erratumOpen access
  PublisherOA PDFDOI

• 3D structure and dynamics of Campi Flegrei enhance multi-hazard assessment

  Nature Communications · 2025-05-23 · 6 citations

  articleOpen access

  Campi Flegrei is an active caldera in a populated area, currently experiencing significant ground uplift and seismicity. Leveraging seismicity relocations, here we obtain high resolution, 3D P- and S-wave seismic images which we combine with a tailored rock physics experiment to define key features of the caldera’s structure: gas-rich reservoir below 2 km depth, deformed caprock at 1–2 km depth, and basement below 3.5 km depth. Seismicity migrates downwards from the caprock and changes in stress loading trigger deeper, higher events along the inner-caldera boundary faults. The reservoir closely correlates the area of maximum uplift, where deformation acceleration due to pore-fluid pressure is corroborated by laboratory experiments using site-relevant rock. The interaction between the pressurized gas-reservoir and the confining caprock drives the ground uplift. Our results indicate that seismic activity and the potential for a phreatic explosion should be considered as plausible scenarios, prompting a re-evaluation of the hazard assessment. This study maps Campi Flegrei caldera’s internal structure, linking a gas-enriched reservoir and a deformed caprock to ground uplift and earthquakes. Land instability, seismic events and the risk of a phreatic explosion prompt for updated multi-hazard assessments.

  PublisherOA PDFDOI

• A Deep-Learning P-Wave Arrival Picker for Laboratory Acoustic Emissions: Model Training and Its Performance

  Rock Mechanics and Rock Engineering · 2024-12-08 · 4 citations

  article
  PublisherDOI

• The Role of Wellbore Cement in Energy Transition: CO2 Storage and Emissions

  2024-06-26

  article1st authorCorresponding

  Abstract Sustainable development demands a fundamental transformation in energy generation, requiring innovations in subsurface management and geomaterial manufacturing. Cement plays a crucial role in facilitating this transition on two fronts. Firstly, as carbon dioxide (CO2) storage emerges as a promising strategy for mitigating emissions from large-scale industrial operations, its effective implementation relies not only on identifying suitable reservoirs with proven storage capacities but also on the performance of wellbore cement in providing long-term mechanical and hydraulic sealing. Secondly, the production of cement demands an environmentally conscious alternative to traditional Portland cement (PC) capable of both curbing CO2 emissions during the calcination process and bolstering the resilience of wellbore casing under pressure. Our research adopts a dual-pronged approach. We investigate the chemical interactions between supercritical CO2 and cement, analyzing their effects on cement porosity, permeability, strength, and failure mechanisms. Concurrently, we explore the properties of a low-carbon cement formulation derived from a volcanic blend composition. This formulation aims to reduce reliance on limestone as a primary resource, thus cutting emissions and minimizing reactivity with CO2. Our findings reveal that exposure to CO2 triggers well-documented carbonation reactions in Portland-based cement, commonly used in older and legacy wells. These reactions lead to calcite mineralization within the cement pore space, resulting in decreased porosity, reduced permeability, and increased strength. While these outcomes show promise for effectively sealing stored CO2 and furthering sustainability goals, it is crucial to note that increased strength does not necessarily correlate with improved toughness. Our findings underscore that calcite mineralization exacerbates cement brittleness and damage, evident from crack propagation detected through acoustic emissions (AEs) monitoring. Over time, crack development worsens fluid flow and heightens the susceptibility of calcite to dissolution in the presence of acidic fluids generated by continuous CO2 injection. Conversely, the volcanic-based formulation yielded lightweight cement samples with density ranging from 1100 kg/m3 to 1300 kg/m3 and a remarkable CO2 reduction of up to 85%. The microstructure resulting from the volcanic blend composition enables ductile mechanical behavior, with peak strength and permeability ranging between 30MPa to 46MPa and 680μD to 30μD, respectively, thus appearing promising when cement is exposed to CO2.

  PublisherDOI

• Enhancing the Passive Monitoring of the Rock Damage Process

  2024-06-26

  article

  Abstract This study explores the effectiveness of double-difference event location methods in detecting early signs of cracking, leading to leaks from structurally trapped CO2. Leaks carry the potential to escalate into bursts, highlighting the importance of proactive pore-pressure management measures. While the double-difference method is frequently applied for precise identification of fluid-induced seismic events, its reliance on a constant velocity model poses limitations, especially in dynamic environments potentially undergoing fracturing. Consequently, integrating velocity variations within a fractured medium into time-lapse seismic localization remains a significant challenge. In this study, we investigate how point-in-time average velocity changes influence the accuracy of double-difference event location. We analyze acoustic emissions (AEs) data gathered from laboratory experiments to explore this relationship. We performed a triaxial mechanical test on Berea sandstone, monitoring stress, strain, acoustic emissions (AEs), and variations in acoustic velocity as damage accumulated over time. AE event locations were determined using P-wave arrival times and magnitudes derived from source-receiver distances. The test revealed a significant surge in AE activity during the stages of damage progression, characterized by crack propagation ultimately leading to failure. Conventional double-difference technique, which assumes constant velocity, led to clustered distributions of acoustic emissions (AEs) that inaccurately represented fracture geometry. However, integrating point-in-time velocity changes improved the alignment of AE distributions with fracture geometry, unveiling a clear time-lapse imaging of crack initiation, propagation, and coalescence along the primary stress direction. This study highlights the crucial role of temporal velocity variations in ensuring precise event mapping, particularly in the monitoring of CO2 leaks. It proposes that average velocity fluctuations be monitored during injection or estimated from rock physics models for continuous and cost-effective monitoring. Ultimately, integrating time-lapse velocity changes improves our capacity to monitor crack progression and mitigate risks associated with CO2 leakage.

  PublisherDOI

• Using acoustic velocities and microimaging to probe microstructural changes caused by thermal shocking of tight rocks

  Frontiers in Earth Science · 2023 · 5 citations

  Senior authorCorresponding
  • Geology
  • Mineralogy
  • Materials science

  Introduction: Large scale, Earth processes and bulk rock properties are influenced by underpinning, dynamic, microstructures within rocks and geomaterials. Traditionally, the amount of porosity has been considered the primary control on important bulk rock properties like seismic wave velocities (Vp and Vs) and permeability. However, in tight rocks, velocity and permeability ( k ) can change substantially despite small changes in the amount of porosity during cracking. Therefore, other microstructural features inherent to given lithologies, such as heterogeneity and anisotropy in mineral properties are considered as factors controlling these bulk rock properties. Understanding which microstructural features control Vp, Vs, and permeability in tight rocks is useful in applications like enhanced geothermal systems (EGS), where thermal shocking is used to increase permeability. Thermal shocking involves injecting surface water into the subsurface to cool mineral crystals, induce contraction of crystals, and cause thermal cracking. Methods: We tested three tight lithologies with unique microstructures; granodiorite (SWG), basalt (PTB), and carbonate (MSA). We simulated thermal shocking by slowly heating samples to 350°C and then quenching them. We chose a temperature of 350°C because thermal shocking at this temperature is not well documented in literature, and this temperature is relevant to EGS. Using time-lapse microimaging, we assessed how thermal cracking occurs in each lithology and explored how thermal cracks influence connected porosity, Vp, Vs, and k. Results: Microimaging shows extensive cracking in the SWG and MSA lithologies, and little to no cracking in PTB with thermal shocking treatment. Vp and Vs became more pressure sensitive, and elastic moduli decreased with treatment for all lithologies. This may be caused by reduced stiffness between mineral crystal boundaries with treatment. Discussion: Lithologies with minerals that have anisotropy of or a wide range in thermal conductivity and/or thermal expansion coefficients can have increased thermal cracking. In thermally shocked SWG and MSA, Vp and Vs are good indicators of thermal cracking and k increases, but less so in PTB. Lithologies like PTB may require multiple thermal shock stimulations to increase permeability. Our results highlight how micro-scale changes influence bulk rock properties and when we can monitor permeability increases and microscale thermal cracking with Vp and Vs.

  PublisherOA PDFDOI

• Corrigendum: Using acoustic velocities and microimaging to probe microstructural changes caused by thermal shocking of tight rocks

  Frontiers in Earth Science · 2023-04-03

  erratumOpen accessSenior author

  CORRECTION article Front. Earth Sci., 03 April 2023Sec. Solid Earth Geophysics Volume 11 - 2023 | https://doi.org/10.3389/feart.2023.1179277

  PublisherOA PDFDOI

• Hydrothermal formation of fibrous mineral structures: The role on strength and mode of failure

  Frontiers in Earth Science · 2023-01-06 · 2 citations

  articleOpen access1st authorCorresponding

  Studying the mechanisms that control the rheology of rocks and geomaterials is crucial as much for predicting geological processes as for functionalizing geomaterials. That requires the understanding of how structural arrangements at the micro and nano scale control the physical and mechanical properties at the macroscopic scale. This is an area of rock physics still in its infancy. In this paper, we focus the attention on the formation of cementitious phases made of micro- and nano-scale fibrous structures, and the controls of the arrangement of these phases on mechanical properties. We use hydrothermal synthesis, and the properties of hydrothermal water, to promote the growth of fibrous mineral phases having nano-size diameter and length of a few microns, creating disordered and entangled mats of fibrous bundles as those found in natural samples. We draw inferences from structural microscopy to inform a statistical model that establishes an interdependence between structural parameters of fibrous structures and bulk mechanical response. Structural parameters include number and length of fibers, spatial orientation, and fraction of fibrous threads bearing the load. Mechanical properties include strength and mode of failure. Results show that as the fibrous microstructure evolves from ordered and aligned to disordered and entangled, the mechanical response of the fibrous composite transitions from a brittle to ductile behavior. Furthermore, the disordered and entangled microstructure exhibits lower strength at failure though strength increases as the number of fibers within the microstructure increases. Finally, the longer the entangled fiber, the larger the strain that the matrix can accommodate. The value of this study lies in further understanding fault healing through hydrothermal fluids and how the physical properties of fibrous microstructures resulting from it control brittle-ductile transitions, and possibly, slow slip events along subduction zones.

  PublisherOA PDFDOI

Recent grants

• Physical and Mechanical Response of the Cementation of Aluminosilicate Seals

  NSF · $500k · 2022–2025

• CAREER: Experimental Investigation For the Characterization of the Geophysical Response of Rock-Fluid Interactions

  NSF · $532k · 2015–2020

Frequent coauthors

• Gary Mavko

  Stanford University

  32 shared

• A. Clark

  Stanford University

  27 shared

• J. Virieux

  Institut des Sciences de la Terre

  13 shared

• Jack Dvorkin

  13 shared

• Aldo Zollo

  University of Naples Federico II

  10 shared

• Adam D. Jew

  10 shared

• John Bargar

  Environmental Molecular Sciences Laboratory

  10 shared

• Tor Arne Johansen

  Norwegian University of Science and Technology

  9 shared

Labs

• Rock Physics and Geomaterials LabPI