Publication

Ryoichiro Agata, Tomohisa Okazaki: Functional-prior-based approaches to Bayesian PDE-constrained inversion using physics-informed neural networks. Computer Methods in Applied Mechanics and Engineering, 461, 119280, 2026. doi: https://doi.org/10.1016/j.cma.2026.119280

Ryoichiro Agata, Satoru Baba, Ayako Nakanishi, Yasuyuki Nakamura: Rapid Hypocenter Determination Tool for the Nankai Trough Subduction Zone Using Physics-informed Neural Networks. Seismological Research Letters, 2026. doi: https://doi.org/10.1785/0220240377

Ryoichiro Agata: Quantification of Uncertainty and Its Propagation in Seismic Velocity Structure and Earthquake Source Inversion. Journal of the Seismological Society of Japan. 2nd ser. (地震 第2輯), 2025. English preprint available: https://arxiv.org/abs/2411.17997

Ryoichiro Agata, Kazuya Shiraishi, Gou Fujie: Physics-informed deep learning quantifies propagated uncertainty in seismic structure and hypocenter determination. Scientific Reports, 15, 1846, 2025. doi: https://doi.org/10.1038/s41598-024-84995-9 (open access)

Ryoichiro Agata, Kazuya Shiraishi, Gou Fujie: Bayesian seismic tomography based on velocity-space Stein variational gradient descent for physics-informed neural network. IEEE Transactions on Geoscience and Remote Sensing, vol. 61, pp. 1-17, Art no. 4506917, 2023.

Ryoichiro Agata, Nakata, R., Kasahara, A., Yagi, Y., Seshimo, Y., Yoshioka, S., & Iinuma, T.: Bayesian Multi-Model Estimation of Fault Slip Distribution for Slow Slip Events in Southwest Japan: Effects of Prior Constraints and Uncertain Underground Structure. Journal of Geophysical Research: Solid Earth, 127(8), e2021JB023712, 2022.

Ryoichiro Agata, Amato Kasahara and Yuji Yagi: A Bayesian inference framework for fault slip distributions based on ensemble modeling of the uncertainty of underground structure — With a focus on uncertain fault dip. Geophysical Journal International, 225(2), 1392-1411, 2021.

Takane Hori*, Ryoichiro Agata*, Tsuyoshi Ichimura, Kohei Fujita, Takuma Yamaguchi, Takeshi Iinuma: High Fidelity Elastic Green's Functions for Subduction Zone Models Consistent With the Global Standard Geodetic Reference System. Earth, Planets and Space, 73(1), 1-12, 2021. (* Equal contributors)

Ryoichiro Agata, Takane Hori, Sylvain D. Barbot, Mamoru Hyodo and Tsuyoshi Ichimura: Quasi-static Simulation Method of Earthquake Cycles Based on Viscoelastic Finite Element Modeling. In: Itou H., Hirano S., Kimura M., Kovtunenko V., Khludnev A. (eds) Mathematical Analysis of Continuum Mechanics and Industrial Applications III. CoMFoS 2018. Mathematics for Industry, vol 34, 2020. doi: https://doi.org/10.1007/978-981-15-6062-0_11

Ryoichiro Agata: Introduction of covariance components in slip inversion of land and seafloor geodetic data and application to slip deficit rate estimation in the Nankai Trough subduction zone. Geophysical Journal International, 221(3):1832-1844, 2020. doi: 10.1093/gji/ggaa116

Ryoichiro Agata, Sylvain D. Barbot, Kohei Fujita, Mamoru Hyodo, Takeshi Iinuma, Ryoko Nakata, Tsuyoshi Ichimura, and Takane Hori: Rapid mantle flow with power-law creep explains deformation after the 2011 Tohoku mega-quake. Nature Communications, 10(1), 1385, 2019.

Ryoichiro Agata, Takane Hori, Keisuke Ariyoshi and Tsuyoshi Ichimura: Detectability analysis of interplate fault slips in the Nankai subduction thrust using seafloor observation instruments. Marine Geophysical Research, 2019. doi: https://doi.org/10.1007/s11001-019-09380-y

Ryoichiro Agata, Tsuyoshi Ichimura, Takane Hori, Kazuro Hirahara, Chihiro Hashimoto and Muneo Hori: An adjoint-based simultaneous estimation method of the asthenosphere's viscosity and afterslip using a fast and scalable finite element adjoint solver. Geophysical Journal International, 213(1), 461-474, 2018.

Ryoichiro Agata, Tsuyoshi Ichimura, Kazuro Hirahara, Mamoru Hyodo, Takane Hori and Muneo Hori: Robust and portable capacity computing method for many finite element analyses of a high-fidelity crustal structure model aimed for coseismic slip estimation. Computers & Geosciences, 94, 121-130, 2016.

Ryoichiro Agata, T. Ichimura, K. Hirahara, M. Hyodo, T. Hori, C. Hashimoto and M. Hori: Numerical Verification Criteria for Coseismic and Postseismic Crustal Deformation Analysis with Large-scale High-fidelity Model. Procedia Computer Science, 51, 1534-1544, 2015. (Presented at International Conference on Computational Science 2015, Reykjavik, Iceland)

Ryoichiro Agata, T. Ichimura, K. Hirahara, M. Hyodo, T. Hori and M. Hori: Several Hundred Finite Element Analyses of an Inversion of Earthquake Fault Slip Distribution using a High-fidelity Model of the Crustal Structure. Procedia Computer Science, 29, 877-887, 2014. (Presented at International Conference on Computational Science 2014, Cairns, Australia)

Ryoichiro Agata, T. Ichimura, M. Hyodo, T. Hori, K. Hirahara and M. Hori: Fundamental Research for Improving Fault Scenario — Development of a Method for Crustal Deformation Analysis Using High-Fidelity Three-Dimensional Crustal Structure. Journal of Japan Society of Civil Engineers, Ser. A1 (Structural Engineering & Earthquake Engineering (SE/EE)), 69(4), I_767-I_776, 2013 (in Japanese with English abstract).

Tomohisa Okazaki, Ryoichiro Agata, Masayuki Kano, Takeo Ito, Kazuro Hirahara, and Naonori Ueda: Fault geometry invariance and differentiable ensemble solutions for simultaneous fault and slip inversion in heterogeneous crustal structures. Journal of Geophysical Research: Machine Learning and Computation, 3(4), e2026JH001323, 2026.

Tomohisa Okazaki, Takeo Ito, Kazuro Hirahara, Ryoichiro Agata, Masayuki Kano, and Naonori Ueda: Three-dimensional crustal deformation analysis using physics-informed deep learning. Journal of Geophysical Research: Solid Earth, 131, e2025JB032618, 2026. doi: https://doi.org/10.1029/2025JB032618

Shinji Yamashita, Yuji Yagi, Ryo Okuwaki, Kousuke Shimizu, Ryoichiro Agata, Yukitoshi Fukahata: Potency density tensor inversion of complex body waveforms with time-adaptive smoothing constraint. Geophysical Journal International, vol. 231, issue 1, pp. 91-107, Oct 2022. doi: https://doi.org/10.1093/gji/ggac181

Tomita, F., Iinuma, T., Ryoichiro Agata, & Hori, T. (2021): Development of a Trans-Dimensional Fault Slip Inversion for Geodetic Data. Journal of Geophysical Research: Solid Earth, 126(5), e2020JB020991.

Shinji Yamashita, Yuji Yagi, Ryo Okuwaki, Kousuke Shimizu, Ryoichiro Agata, Yukitoshi Fukahata: Consecutive ruptures on a complex conjugate fault system during the 2018 Gulf of Alaska earthquake. Scientific Reports, 11, 5979, 2021.

Masaru Nakano, Shane Murphy, Ryoichiro Agata, Yasuhiko Igarashi, Masato Okada, Takane Hori: Self-similar stochastic slip distributions on a non-planar fault for tsunami scenarios for megathrust earthquakes. Progress in Earth and Planetary Science, 7, 45, 2020. doi: https://doi.org/10.1186/s40645-020-00360-0

Tsuyoshi Ichimura, Ryoichiro Agata, Takane Hori, Kenji Satake, Kazuto Ando, Toshitaka Baba and Muneo Hori: Tsunami Analysis Method with High-Fidelity Crustal Structure and Geometry Model. Journal of Earthquake and Tsunami, 1750018, 2017.

Takuma Yamaguchi, Tsuyoshi Ichimura, Yuji Yagi, Ryoichiro Agata, Takane Hori and Muneo Hori: Fast crustal deformation computing method for multiple computations accelerated by a graphics processing unit cluster. Geophysical Journal International, 210(2), 787-800, 2017.

Takuma Yamaguchi, Ryoichiro Agata, Tsuyoshi Ichimura, Muneo Hori and Lalith Wijerathne: A Monte Carlo analysis method of crustal deformation computation on GPU clusters. Journal of Japan Society of Civil Engineers, Ser. A1 (Structural Engineering & Earthquake Engineering (SE/EE)), 73(4), 2017 (in Japanese with English abstract).

Tsuyoshi Ichimura, Ryoichiro Agata, Takane Hori, Kazuro Hirahara, Chihiro Hashimoto, Muneo Hori and Yukihiro Fukahata: An Elastic/Viscoelastic Finite Element Analysis Method for Crustal Deformation using a 3D Island-scale High-fidelity Model. Geophysical Journal International, 206(1), 114-129, 2016.

Tsuyoshi Ichimura, Ryoichiro Agata, Takane Hori, Kazuro Hirahara and Muneo Hori: Fast numerical simulation of crustal deformation using a three-dimensional high-fidelity model. Geophysical Journal International, 195(3), 1730-1744, 2013.