@inseismoland
Associate Professor Scripps Institution of Oceanography UCSD, Guest Prof LMU Munich, EGU Seismology Division President, earthquake source philosopher, high-performance computing enthusiast, mommy
To mark 20 years of #SeisSol and 10 years of #ExaHyPE, Michael Bader, @tobiasweinzierl.bsky.social, and I organize a Workshop, Training & Hackathon at LRZ (near Munich), June 11–12, 2026. Contributed talks (Jun 11) and training + hackathon tracks (Jun 12)
Registration: events.hifis.net/event/3608/
This work quantitatively links megathrust properties such as fluid pressure and fault strength to slow slip cycle characteristics and enables dense parameter exploration with quantified uncertainties
doi.org/10.1093/gji/...
constraints on the upper frictional transition zone. It also helps to characterize the width of the assumed deep, low-effective-normal-stress megathrust portion and the locally low effective normal stress (3.8 ± 1.4 MPa).
The approach reduces computational cost by ~3.5 × 10^5 relative to the volumetric full-order SEAS simulations, which makes Bayesian MCMC inversion feasible.
Using Northern Cascadia slow slip observations as constraints, this inversion indicates near-lithostatic pore-fluid pressure and places depth..
cost by orders of magnitude. In this study Yohai builds a two-step ROM for rate-and-state slow slip cycles in a Cascadia-like 2D subduction setting, using a spline-based latent-space representation and Proper Orthogonal Decomposition (POD) with radial-basis-function interpolation (iPOD) ...
physics-based model into a low-dimensional representation constructed from a training set of full-order runs, then emulate new parameter choices by interpolating within that reduced space, without rerunning costly simulations. The goal is to preserve the governing physics while reducing the ...
New paper in press at GJI led by postdoc Yohai Magen (with Dave May and I): “Reduced-order modelling of Cascadia’s slow slip cycles” (doi.org/10.1093/gji/...).
Reduced-order models (ROMs) are fast surrogates of costly simulations. They compress the evolving, high-dimensional state of a ...
and more broadly to probing wave propagation in media that vary in both space and time with a controlled "switch" in material properties.
By scaling Lamé parameters and density in specific ways, we can mirror the full body-wavefield, or selectively mirror only P waves or only S waves. That opens up new paths to synthesizing converging wavefields for imaging-style experiments,
At a time boundary the wavenumber stays fixed while the frequency shifts, so the reflected/transmitted wavelets can move to higher (or lower) frequencies depending on the imposed material property changes.
Another useful aspect for seismology is the control an ITM provides.
the usual diverging wavefield. We implement ITM physics in SeisSol (based on ADER-DG) and validate the implementation based on an eigenvector-based analytical framework for general linear hyperbolic systems to interpret time-boundary behavior and energy balance.
Instead of a spatial interface that reflects waves in space, we impose a very short, controlled change of elastic parameters everywhere in a model. This time interface generates a time-reflection throughout the volume which produces a converging wavefield, or a focal spot, in addition to
In our new Geophysical Journal International paper, Vikas Kurapati, Gregor Hillers, Lukas Krenz, Michael Bader and I, bring the ITM concept from physics into the realm of numerical 3D elastic seismic wave propagation.
academic.oup.com/gji/advance-...
Instantaneous time mirrors (ITMs), creating a "time interface" by abruptly changing material properties, have fascinated physicists for decades. Experiments demonstrating time mirrors for optical and electromagnetic waves exist. But can we also “reflect” a 3D seismic wavefield in time?
Laura Wallace, Lian Xue, Yusuke Yokota, Shoichi Yoshioka, Shui-Beih Yu
Bertrand Lovery, Louise Maubant, Sylvain Michel, Cyril Muller, Marianne Métois, Takuya Nishimura, Akemi Noda, Dibyashakti Panda, Mason Perry, Raymundo Omar Plata Martínez, Mathilde Radiguet, Baptiste Rousset, Elizabeth Sherrill, Anne Socquet, Juan Carlos Villegas-Lanza,
Julie Elliott, Andria Ellis, Lujia FENG, Jeff Freymueller, Endra Gunawan, Nuraini Rahma Hanifa, George Hilley, Ya-Ju Hsu, Takeshi Iinuma, Yuji Itoh, Jorge Jara, Kaj Johnson, Romain Jolivet, Masayuki Kano, Emilie Klein, Shanshan Li, Shaoyang Li, Eric Lindsey, Zhen Liu, John Loveless,
Link to the Coupling Cloud website:
couplingcloud.ucsd.edu
Link to the preprint:
eartharxiv.org/repository/v...
led by Bar Oryan, with Roland Bürgmann, Eric Calais, Guo Cheng, Mohamed Chlieh, Beatriz Cosenza-Muralles, Víctor M. Cruz-Atienza, Luca Dal Zilio, Charles DeMets,
when models are examined one-by-one. The Coupling Cloud is designed to grow through community contributions of observational datasets and models, to hopefully serve as a long-lived resource for advancing understanding of megathrust deformation and seismic hazard.
download the full dataset in standardized, machine-readable formats (NetCDF for coupling, VTU for interface geometry, YAML for metadata). We also demonstrate, with a simple Cascadia example, how synthesizing multiple full-margin models can reveal along-strike patterns that are difficult to see
21 subduction zones, assembled by a team of 51 coauthors. The browser-based platform provides interactive 2D and 3D viewers to inspect kinematic coupling on the plate interface alongside original publication information, slab geometry, uncertainty information, and metadata, and it lets users
A new preprint, led by Bar Oryan, introduces the Coupling Cloud: a community database that curates, standardizes, documents, and disseminates published kinematic coupling models inverted from geodetic data. As of today it brings together 96 coupling datasets drawn from 55 publications spanning
and for linking surface fault patterns to lithospheric-scale strain localization.
outward-propagating thrusts), duplex systems (interacting parallel faults connected by P-shears), and non-interacting parallel fault arrays. These results help to mechanistically interpret contrasts between the Levant Fault system and the Jamaican fault network,
that allow spontaneous fault localization, so transpression emerges without imposing velocity discontinuities. By systematically varying the position and geometry of inherited weak zones, the paper recovers three end-member outcomes: push-up systems (a single strike-slip fault with ...
Why do some strike-slip restraining bends build narrow push-up ranges, while others evolve into distributed duplex fault networks? This study uses 3D thermo-mechanical lithospheric models with temperature-dependent, non-linear rheology and heterogeneous simple-shear boundary conditions ...
New paper alert! "Lithospheric models supported by the Caribbean and Levant examples help rethink transpression at plate boundaries" led by Anthony Jourdon,
@laetitialp.bsky.social, Dave May, Manuel Pubellier, open access in Nature Comms:
www.nature.com/articles/s41...
@natureportfolio.nature.com
The star represents the epicenter of the magnitude for earthquake, and the color show the shaking intensity generated by that event
Location of the earthquakes that have occurred near San Ramon in the last hour
The San Ramon earthquake swarm ramping up this evening with a M4.0 and couple of M3.8’s. Busy little swarm.
Did you feel it? Report it?
earthquake.usgs.gov/earthquakes/...
Group photo with Jeena Yun Jonatan Glehman John Rekoske Evan Marschall Yohai Magen Fabian Kutschera Jeremy Wing Ching Wong Gabrielle Hobson Bar Oryan Nico Schliwa and missing Baoning Wu
#AGU25 is a wrap! So many inspiring and thought-provoking posters and presentations. A meeting like this is not only about scientific excellence but also about new and old connections, science communication and collaboration!