Seismology · Deep Earth Structure and Dynamics

Imaging the deep interior of the Earth

The Wolf Group uses seismic waves to probe the structure and dynamics of the Earth's mantle and core. We develop waveform-based methods to constrain anisotropy, flow, and the boundaries between the planet's deepest layers.

About the Wolf Group

Led by assistant professor Jonathan Wolf, our group studies how seismic waves interact with the Earth's mantle and core. We combine observational seismology with numerical modeling to turn recordings of distant earthquakes into images of structures thousands of kilometers below the surface.

We are committed to open, reproducible science: our methods, code, and figures are shared openly so that results can be checked, reused, and built upon by the wider community.

Our research

Differential splitting intensity map

Theme 01

Mantle dynamics

We measure seismic anisotropy, the directional dependence of wave speeds, to map the direction of flow in the deep mantle and connect it to the convection that drives the plates above.

Cutaway globes of the African and Pacific LLVPs

Theme 02

Earth's interior structure

We image fine-scale features at the base of the mantle, including ultra-low velocity zones (ULVZs), to understand the composition, origin, and evolution of the deepest Earth.

Stacked Sdiff waveforms

Theme 03

Seismic data collection

We download, process, and maintain large global seismic datasets, including ADEPT, that form a shared, consistent foundation for our imaging and for our collaborators' work.

Seismic data & open software

Building and maintaining the ADEPT dataset

Much of our imaging rests on ADEPT, a massive, continuously growing archive of global seismic waveforms that we download, process, and curate specifically for deep-Earth research.

We build and maintain this dataset in collaboration with colleagues at Arizona State University, giving the group and our partners a single, consistent foundation behind nearly every image we produce of Earth's interior.

Global distribution of seismic stations and earthquakes in the ADEPT dataset

Global distribution of seismic stations (black) and earthquakes (red) in the ADEPT dataset.

Selected publications

Names in bold are Jonathan Wolf and advisees.

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Questions about our research?

Feel free to reach out — we're happy to hear from you.

Meet the Group

The people behind the science

Jonathan Wolf

Jonathan Wolf

Assistant Professor · Principal Investigator · UC Santa Cruz

Jonathan studies the structure and dynamics of Earth's deep interior. His work centers on seismic anisotropy in Earth's mantle, using it to map how rock flows and deforms. He also images the deep mantle's fine-scale structure, from ultra-low velocity zones (ULVZs) and D″ to the large low-velocity provinces (LLVPs). Much of it rests on large, uniformly processed global datasets paired with full-wavefield modeling.

He earned his PhD at Yale University, advised by Maureen D. Long. Before joining the UC Santa Cruz faculty in 2026, he was a Miller Institute Postdoctoral Scholar at UC Berkeley hosted by Barbara Romanowicz and Weiqiang Zhu.

Projects

What we work on

Our research runs along three connected threads: imaging how the deep mantle flows, resolving Earth's deep structure, and building the seismic data and methods that make both possible.

Differential splitting intensity map

Theme 01

Mantle dynamics

We use seismic anisotropy, the directional dependence of seismic wave speeds, to map how rock flows and deforms in the deep mantle. By uniformly processing shear-wave splitting from a massive global dataset and testing it against geodynamic models, we tie deformation at the base of the mantle to subducted slabs, plume roots, and the edges of large low-velocity provinces, from the Yellowstone plume and the Perm Anomaly to the lowermost mantle beneath Alaska and the Indian Ocean.

Cutaway globes of the African and Pacific LLVPs

Theme 02

Earth's interior structure

We image fine-scale structure at the base of the mantle and across the core–mantle boundary, including ultra-low velocity zones (ULVZs), D″ reflectors, and outermost-core structure. Combining core-sensitive phases such as SKS, SmKS, and Sdiff with full-wavefield modeling, we resolve where dense, low-velocity material gathers, beneath the Himalayas, the central Pacific, and North America, and how mantle flow redistributes it over time.

Stacked Sdiff waveforms

Theme 03

Seismic data collection

Underpinning both efforts is ADEPT, a massive, continuously growing archive of global seismic waveforms maintained by John D. West at Arizona State University. We download, process, and curate from it for deep-Earth research, and pair it with open methods and software, automated splitting workflows and the AxiSEM3D wavefield solver, to produce uniformly processed, reproducible datasets for the group and the wider community.

Publications

Publication Library

Names in bold are Jonathan Wolf and advisees.

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Illustrations

Illustrations

Interactive views you can turn over in your hands, and library of figures from our publications.

Interactive

Explore in three dimensions

Interactive 3D globes of the shear-wave tomographic agreement field beneath the Pacific and African provinces

Consensus rank field, VS: the two provinces

Two independently orbiting globes, framed on the Pacific and African provinces, showing where shear-wave tomography models agree that velocity is high (blue) or low (orange).

Tomographic agreement model, in prep.

Launch interactive ↗ Interactive 3D · ~20 MB on first load · needs WebGL
Interactive 3D globes of the compressional-wave tomographic agreement field beneath the Pacific and African provinces

Consensus rank field, VP: the two provinces

Two independently orbiting globes, framed on the Pacific and African provinces, showing where compressional-wave tomography models agree that velocity is high (blue) or low (orange).

Tomographic agreement model, in prep.

Launch interactive ↗ Interactive 3D · ~17 MB on first load · needs WebGL

Animations

Watch the wavefield

Sdiff passing an ultralow velocity zone

A full wavefield AxiSEM3D simulation of a diffracted S wave crossing an ultralow velocity zone at the core mantle boundary.

Wolf, J., et al., Detection of lowermost mantle heterogeneity using seismic migration of diffracted S-waves, JGR: Solid Earth (2025)

Journal ↗ Video · 0.8 MB · 22 s

Figures

Figure Library

Selected figures from our publications.

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Contact

Contact Jonathan

Office

Department of Earth and Planetary Sciences
University of California, Santa Cruz
1156 High Street
Santa Cruz, CA 95064

Prospective students

If you're interested in joining the group as a graduate student or postdoc, please reach out by email with a short note about your background, your research interests, and why the group appeals to you, and attach your CV.

Send an email