## Research Interests

- Mathematical modeling of earthquake fault mechanics
- Dynamic rupture along and crossing with a material interface
- Earthquake energy estimation based on inversion analyses
- Determination mechanisms of rupture velocity
- Unilateral rupture along very long reverse faults
- Slip/stress heterogeneity and foreshock-mainshock-aftershock sequences
- Source time functions based on a stochastic differential equation
- Seismicity data analysis
- Objective threshold determination of a matched-filter technique for seismic event detection based on the extreme value theory and an information criterion
- Seismic event-pair detection by similarity thresholding.
- Laboratory seismology
- Elastodynamics and rheorogy of sand after strong vibration or water injection
- Dynamic shear rupture in a photoelastic medium

## Antecedents

- Assistant professor, Apr. 2015 -- present
- Department of Physical Science, College of Science and Engineering, Ritsumeikan University, Japan
- Teaching Earth Science/Laboratory Works in Earth Science
- Postdoctoral fellow, Oct. 2013 -- Mar. 2015
- Mega Quake Risk Management Project / Faculty of Engineering, Information and Systems, Tsukuba University, Japan
- PhD course, Apr. 2009 -- Sep. 2013
- Earthquake Research Institute / Department of Earth and Planetary Science, Graduate School of Science, University of Tokyo, Japan
- supervised by Teruo Yamashita and Nobuki Kame
- Internship, Jul. 2011 -- Aug. 2011
- School of Engineering and Applied Science, Harvard University, U.S.
- hosted by James R. Rice
- Master's course, Apr. 2007 -- Mar. 2009
- Earthquake Research Institute / Department of Earth and Planetary Science, Graduate School of Science, University of Tokyo, Japan
- supervised by Teruo Yamashita
- Undergraduate course, Apr. 2003 -- Mar. 2007
- Department of Mathematics, Faculty of Science, Tokyo University of Science, Japan
- supervised by Keiichi Kato

## Publications

### Submitted manuscripts

- Hirano, S., Kawakata, H. & Doi, I. (under review)
- A matched-filter technique with an objective threshold
- submitted to
*Scientific Reports* *ESSOAr*: Earth and Space Science Open Archive, doi:10.1002/essoar.10504044.2

### Peer-reviewed journal papers

- Hirano, S. (2022)
- Source time functions of earthquakes based on a stochastic differential equation
*Scientific Reports*,**12**:3936, doi:10.1038/s41598-022-07873-2- Numerical results in an ascii format:
*OSF*: Open Science Framework, doi:10.17605/OSF.IO/VUXJ6 - Nakayama, M., Kawakata, H., Hirano, S., & Doi, I. (2021)
- Development of a laboratory monitoring system for elastic waves transmitted through sand under dry and saturated conditions
*Earth Planet Space*,**73**(25), doi:10.1186/s40623-020-01346-4- Hirano, S., & Itou, H. (2020)
- Parameter interdependence of dynamic self-similar crack with distance-weakening friction
*Geophys. J. Int.*,**223**(3):1584--1596, doi:10.1093/gji/ggaa392-
## Erratum

eq. (7) must be $L(x) = \displaystyle \log\left|\frac{1-x}{1+x}\right|$ (absolute value symbol was missing)

$\Delta \sigma_b$ in eqs.(C1)(C5)(C6)(C7) and next line to eq.(C9) must be $\sigma_b$.

- Okuwaki, R., Hirano, S., Yagi, Y., & Shimizu, K. (2020)
- Inchworm-like source evolution through a geometrically complex fault fueled persistent supershear rupture during the 2018 Palu Indonesia earthquake
*Earth Planet. Sci. Lett.*,**547**(2020):116449, doi:10.1016/j.epsl.2020.116449*EarthArXiv Preprints*, doi:10.31223/osf.io/j4cas*OSF*: Open Science Framework, doi:10.17605/OSF.IO/8AZ3G- Hirano, S. (2019)
- Modeling of unilateral rupture along very-long reverse faults
*J. Geophys. Res.*,**124**(1):1057--1071, doi:10.1029/2018JB016511.- Okuwaki, R., Kasahara, A., Yagi, Y., Hirano, S. & Fukahata, Y. (2019)
- Backprojection to image slip
*Geophys. J. Int.*,**216**(3):1529--1537, doi:10.1093/gji/ggy505.- Tamaribuchi, K., Yagi, Y., Enescu, B. & Hirano, S. (2018)
- Characteristics of foreshock and aftershock activity inferred from the JMA earthquake catalog improved by automatic processing
*Earth Planet Space*,**70**:90, doi:10.1186/s40623-018-0866-9.- Hirano, S. & Yagi, Y. (2017)
- Dependence of seismic and radiated energy on shorter wavelength components
*Geophys. J. Int.*,**209**(3):1585--1592, doi:10.1093/gji/ggx108.- Hirano, S. & Yamashita, T. (2016)
- Modeling of interfacial dynamic slip pulses with slip-weakening friction
*Bull. Seism. Soc. Am.***106**(4):1628--1636, doi: 10.1785/0120150208.## Erratum

$\displaystyle \frac{1}{1+S}$ in eqs. (19)(20)(22) must be $\displaystyle - \frac{1}{1+S}$ (minus sign was missing)

- Self archive of a pre-copyedit version
- Hirano, S. & Yamashita, T. (2015)
- Dynamic anti-plane rupture propagation crossing a material interface: modelling with BIEM
*Geophys. J. Int.***200**(2):1220--1233, doi:10.1093/gji/ggu471.## Erratum

eq. (26) must be $\Psi_l(X) = \displaystyle \sqrt{X^2-\beta_l^{-2}} \arctan{\frac{\eta_l}{\sqrt{X^2-\beta_l^{-2}}}} - \eta_l$ (subscript $l$ of $\beta$ was missing)

- Okuwaki, R., Yagi, Y. & Hirano, S. (2014)
- Relationship between High-frequency Radiation and Asperity Ruptures, Revealed by Hybrid Back-projection with a Non-planar Fault Model
*Scientific Reports,***4**:7120, doi:10.1038/srep07120.- Yagi, Y., Okuwaki, R., Enescu, B., Hirano, S., Yamagami, Y., Endo, S. & Komoro, T. (2014)
- Rupture process of the 2014 Iquique Chile earthquake in relation with the foreshock activity
*Geophys. Res. Lett.,***41**(12):4201--4206, doi: 10.1002/2014GL060274.- Hirano, S. & Yamashita, T. (2011)
- Analysis of the static stress field around faults lying along and intersecting a bimaterial interface
*Geophys. J. Int.***187**(3):1460--1478, doi:10.1111/j.1365-246X.2011.05202.x.

### Peer-reviewed proceeding papers

- Hirano, S. (accepted)
- Résumé: Energy estimation of earthquake faulting processes
*Singularity and asymptotic behavior of solutions for partial differential equations with conservation law: RIMS Kôkyûroku Bessatsu.*- Self archive of a pre-copyedit version
- Hirano, S. (2020)
- Friction vs. damage: dynamic self-similar crack growth revisited
- In: Itou, H. et al. (eds)
*Mathematical Analysis of Continuum Mechanics and Industrial Applications III. CoMFoS18*. Mathematics for Industry, Springer, doi:10.1007/978-981-15-6062-0_12 - Self archive of a pre-copyedit version
- Nakayama, M., Kawakata, H., Hirano, S., Doi, I., & Takahashi, N. (2018)
- Propagation characteristics of elastic waves transmitted through sand soils under dry and saturated conditions
*Progress in Acoustic Emission XIX, Jpn. Soc. Non-Destructive Inspection*, 163--167.- Hirano, S. (2018)
- Integral representation and its applications in earthquake mechanics: a review
- In: van Meurs, P. et al. (eds)
*Mathematical Analysis of Continuum Mechanics and Industrial Applications II. CoMFoS 2016*. Mathematics for Industry, vol 30. Springer, Singapore, doi:10.1007/978-981-10-6283-4_9. - Self archive of a pre-copyedit version
- Hirano, S. (2017)
- Propagation velocity of pulse-like rupture along earthquake faults
- In: Itou, H. et al. (eds)
*Mathematical Analysis of Continuum Mechanics and Industrial Applications*. Mathematics for Industry, vol 26. Springer, Singapore, doi:10.1007/978-981-10-2633-1_10. - Self archive of a pre-copyedit version

### Book

- Itou, H., Hirano, S., Kimura, M., Kovtunenko, V.A., & Khludnev, A.M. (Eds.) (2020)
*Mathematical Analysis of Continuum Mechanics and Industrial Applications III. CoMFoS18*. Mathematics for Industry, Springer, doi:10.1007/978-981-15-6062-0

### Misc.

- Hirano, S., & Okuwaki, R. (2020)
- Note on “Backprojection to image slip”
*OSF*: Open Science Framework, doi:10.17605/OSF.IO/PB7HK- Endo, S., Nakao, A., Hirano, S. & Yagi, Y. (2017)
- The 2013 Sea of Okhotsk deep earthquake: A complex rupture within the Ringwoodite stability zone
*Earth Evol. Sci.*,**11**:23--30.- 桑野修, 平野史朗, 藤田哲史, 日下部哲也, 小寺祐貴, 亀伸樹, 中谷正生, 安藤亮輔 (2011)
- 寒天（アガロースゲル）を用いた断層の動的破壊実験
- 日本地震学会ニュースレター Vol.22 No.6, 表紙

## International Conferences

- Hirano, S.
- Statistics and variability of source time functions based on a stochastic differential equation
- American Geophysical Union 2021 Fall Meeting, New Orleans and Online, December, 2021
- Okuwaki, R., Yagi, Y., Shimizu, K., Fukahata, Y., Hirano, S., Hicks, S.P., Craig, T.J., Fan, W., Goes, S.D.B., and Wright, T.J.
- Accounting epistemic uncertainty in finite-fault inversion: development of a potency-density tensor approach to investigate complex earthquake rupture processes
- American Geophysical Union 2021 Fall Meeting, New Orleans and Online, December, 2021 (Oral, Invited)
- Hirano, S.
- Various inverse problems in seismology: seismic tomography, hypocenter location, earthquake source kinematics, and Earth's crustal stress.
- Control and inverse problems on waves, oscillations and flows - Mathematical analysis and computational methods -, Online, September, 2021 (Oral)
- Hirano, S.
- Theoretical properties of source time functions based on a stochastic differential equation
- Joint Scientific Assembly IAGA-IASPEI 2021, Online, August 26, 2021 (Flash talk & Poster)
- Okuwaki, R., Hirano, S., Yagi, Y., & Shimizu, K.
- Source evolution through a geometrically complex fault system controls supershear rupture during the 2018 Palu earthquake
- FRINGE 2021 (Advances in the Science and Applications of SAR Interferometry and Sentinel-1 InSAR), Online, May 31--June 04, 2021 (Oral)
- Hirano, S., & Itou, H.
- Dynamic antiplane self-similar crack with distance-weakening friction: an analytical solution for source parameter estimation
- American Geophysical Union 2020 Fall Meeting, Online, December 16, 2020 (Flash talk & Poster)
- Go to the poster page.
- Hirano, S.
- An empirical PDE for slip along earthquake faults
- The Second Russia-Japan Workshop "Mathematical analysis of fracture phenomena for elastic structures and its applications" - 20th Conference of Continuum Mechanics Focusing on Singularities (CoMFoS20), Online, December 15, 2020 (Oral)
- Hirano, S.
- A nonlinear integro-differential equation for earthquake faulting
- RIMS Workshop on Analysis of inverse problems through partial differential equations and related topics, Kyoto, Japan, January 09, 2020 (Oral)
- Hirano, S.
- An observation-based differential equation of spatio-temporal slip distribution
- American Geophysical Union 2019 Fall Meeting, San Francisco, U.S., December 13, 2019 (Poster)
- Kakutani, T., Kawakata, H., & Hirano, S.
- Seismic response change of a sand soil after strong motion, revealed by a transmission laboratory experiment
- American Geophysical Union 2019 Fall Meeting, San Francisco, U.S., December 11, 2019 (Poster)
- Nakayama, M., Kawakata, H., Hirano, S., & Doi, I.
- Propagation characteristic changes of elastic waves transmitted through a sand soil in water injection and drainage processes
- American Geophysical Union 2019 Fall Meeting, San Francisco, U.S., December 10, 2019 (Poster)
- Hirano, S.
- Dynamic growth of a self-similar anti-plane crack during earthquakes
- Russia-Japan Workshop "Mathematical analysis of fracture phenomena for elastic structures and its applications", Novosibirsk, Russia, November 12, 2019 (Oral)
- Hirano, S.
- Energy dissipation during dynamic antiplane self-similar crack growth
- CoMFoS19:Mathematical Analysis of Continuum Mechanics and Industrial Applications, Kanazawa, Japan, July 15, 2019 (Oral)
- Hirano, S.
- Analytical solution of dynamic self-similar crack growth under distance-weakening friction
- Numerical Modeling of Earthquake Motions: Waves and Ruptures, Smolenice, Slovakia, July 01--03, 2019 (Poster)
- Hirano, S., Kawakata, H., & Doi, I.
- Foreshock activity detection by a threshold-free matched-filter technique
- Japan Geoscience Union Meeting, Chiba, Japan, May 26, 2019 (Oral)
- Hirano, S.
- Aftershocks and the GR law due to a heterogeneous slip model
- American Geophysical Union 2018 Fall Meeting, Washington D.C., U.S., December 14, 2018 (Oral)
- Nakayama, M., Kawakata, H., Hirano, S., Doi, I., & Takahashi, N.
- 24-hours broadband measurements of elastic waves transmitted through sand soils under dry and saturated conditions to investigate differences in propagation characteristics
- American Geophysical Union 2018 Fall Meeting, Washington D.C., U.S., December 10, 2018 (Poster)
- Nakayama, M., Kawakata, H., Hirano, S., Doi, I., & Takahashi, N.
- Propagation characteristics of elastic waves transmitted through sand soils under dry and saturated conditions
- 24th International Acoustic Emission Symposium, Sapporo, Japan, November 07, 2018 (Oral)
- Hirano, S., Toyomoto, Y., Kawakata, H., & Doi, I.
- Application of Extreme Value Theory to a Matched-Filter Analysis
- 10th ACES International Workshop, Awaji Island, Japan, September 27, 2018 (Poster)
- Hirano, S.
- Friction vs. damage: dynamic self-similar crack growth revisited
- CoMFoS18:Mathematical Analysis of Continuum Mechanics and Industrial Applications, Kyoto, Japan, June 13, 2018 (Oral)
- Hirano, S., Toyomoto, Y., Kawakata, H. & Doi, I.
- Objective matched-filter analysis for dertecting small events
- International Symposium on Earthquake Forecast / 5th International Workshop on Earthquake Preparation Process, ~Observation, Validation, Modeling, Forecasting~, Chiba, Japan, May 25, 2018 (Poster)
- Wakamatsu, S., Kawakata, H. & Hirano, S.
- Observed seismic and infrasonic signals around the Hakone volcano -Discussion based on a finite-difference calculation-
- American Geophysical Union 2017 Fall Meeting, New Orleans, U.S., December 15, 2017 (Poster)
- Hirano, S.
- Mathematical modeling and numerical simulation of unilateral dynamic rupture propagation along very-long reverse faults
- American Geophysical Union 2017 Fall Meeting, New Orleans, U.S., December 14, 2017 (Poster)
- Nakayama, M., Kawakata, H., Hirano, S., Doi, I. & Takahashi, N.
- Improvement in transmission experiment of elastic waves through partially saturated porous sand soil
- American Geophysical Union 2017 Fall Meeting, New Orleans, U.S., December 14, 2017 (Poster)
- Yoneda, N., Kawakata, H., Hirano, S., Yoshimitsu, N. & Takahashi, N.
- Extraction of AE events to estimate their b values under a triaxial compressive condition ~Examination using continuous broadband records~
- American Geophysical Union 2017 Fall Meeting, New Orleans, U.S., December 14, 2017 (Poster)
- Hirano, S.
- Unilateral dynamic rupture propagation along earthquake faults
- CoMFoS17:Mathematical Analysis of Continuum Mechanics and Industrial Applications, OIST, Japan, September 21, 2017 (Oral)
- Hirano, S.
- Energy estimation of earthquake faulting based on a wavefield inversion
- RIMS workshop on "Singularity and asymptotic behavior of solutions for partial differential equations with conservation law", Kyoto, Japan, June 08, 2017 (Oral)
- Hirano, S.
- Integral equation for mechanics of earthquakes
- RIMS workshop on "Inverse problems for partial differential equations and related areas", Kyoto, Japan, January 26, 2017 (Oral)
- Nakayama, M., Kawakata, H., Hirano, S., Doi, I., & Takahashi, N.
- Transmission experiment of elastic waves with short wavelengths through a highly porous sand soil during water injection
- American Geophysical Union 2016 Fall Meeting, San Francisco, U.S., December 15, 2016 (Poster)
- Toyomoto, Y., Kawakata, H., Hirano, S. & Doi, I.
- Foreshock search over a long duration using a method of setting appropriate criteria
- American Geophysical Union 2016 Fall Meeting, San Francisco, U.S., December 15, 2016 (Poster)
- Tsujimura, Y., Kawakata, H., Fukuyama, E., Yamashita, F., Xu, S., Mizoguchi, K, Takizawa, S. & Hirano, S.
- Spatio-temporal foreshock activity during stick-slip experiments of large rock samples
- American Geophysical Union 2016 Fall Meeting, San Francisco, U.S., December 13, 2016 (Poster)
- Hirano, S., Yamashita, T. & Hatano, T.
- Behavior of pulse-like rupture with velocity-time-dependent friction from a granular layer model
- American Geophysical Union 2016 Fall Meeting, San Francisco, U.S., December 12, 2016 (Oral)
- Hirano, S.
- Integral representation and its applications of the mechanics of earthquakes
- CoMFoS16:Mathematical Analysis of Continuum Mechanics and Industrial Applications, Kyushu University, Japan, October 23, 2016 (Oral)
- Hirano, S. & Yamashita, T.
- Propagation velocity of pulse-like rupture with a time-weakening friction law
- American Geophysical Union 2015 Fall Meeting, San Francisco, U.S., December 18, 2015 (Poster)
- Iwata, K., Kawakata, H., Hirano, S., & Doi, I.
- Estimation of Seismic Attenuation beneath Tateyama Volcano, Central Japan by Using Peak Delay
- American Geophysical Union 2015 Fall Meeting, San Francisco, U.S., December 17, 2015 (Poster)
- Imahori, A., Kawakata, H., Hirano, S., Yoshimitsu, N., & Takahashi, N.
- Travel Times of Later Phases for Transmitting Waves through a Fracturing Westerly Granite Sample under a Triaxial Compressive Condition
- American Geophysical Union 2015 Fall Meeting, San Francisco, U.S., December 16, 2015 (Poster)
- Hirano, S.
- Propagation velocity of pulse-like rupture along earthquake fault
- CoMFoS15:Mathematical Analysis of Continuum Mechanics and Industrial Applications, Kyushu University, Japan, November 16, 2015 (Oral)
- Hirano, S. & Yagi, Y.
- Dependence of seismic energy on higher wavenumber components
- American Geophysical Union 2014 Fall Meeting, San Francisco, U.S., December 19, 2014 (Poster)
- Yagi, Y., Okuwaki, R., Enescu, B. & Hirano, S.
- Rupture process of the 2014 Iquique Chile earthquake in relation with the foreshock activity
- American Geophysical Union 2014 Fall Meeting, San Francisco, U.S., December 17, 2014 (Poster)
- Okuwaki, R., Yagi, Y. & Hirano, S.
- Relationship between High-frequency Radiation and Asperity Rupture，Revealed by Hybrid Back-projection with Non-planer Fault
- Seismological Society of America Annual Meeting, Anchorage, U.S., May 01, 2014 (Poster)
- Hirano, S. & Yamashita, T.
- BIEM Simulation for Anti-Plane Dynamic Rupture Propagation across a Bimaterial Interface
- Seismological Society of America Annual Meeting, Anchorage, U.S., April 30, 2014 (Oral)
- Hirano, S.
- An integral representation and numerical simulation of dynamic earthquake faulting occurring in a two-layered medium
- Conference on Diffusion in Heterogeneous Media and Related Topics, Tokyo, Japan, March 06, 2014 (Oral)
- Hirano, S. & Yamashita, T.
- Off Fault Stress Distribution around Dynamic Slip Pulse on a Bimaterial Interface
- The 7th ACES International Workshop, Otaru, Japan, October 04, 2010 (Poster)
- Hirano, S. & Yamashita, T.
- Theoretical analysis of static mode-II crack in two-layered medium - interfacial fault and intersecting fault
- Workshop -Earthquake Source Dynamics: Data and Data-constrained Numerical Modeling, Smolenice Castle, Slovakia, June 28, 2010 (Poster)
- Hirano, S. & Yamashita, T.
- Mathematical and numerical analysis of non-planar static mode-II crack in a two-layered medium
- American Geophysical Union 2009 Fall meeting, San Francisco, U.S., December 17, 2009 (Poster)
- Hirano, S. & Yamashita, T.
- Mathematical and numerical analyses of arbitrarily oriented static mode-II crack in a two-layered medium
- The 7th General Assembly of Asian Seismological Commission and The 2008 Fall meeting of Seismological Society of Japan, Tsukuba, Japan, November 27, 2008 (Poster)

## Award & Grants

- Mar. 2019
- The Young Scientist Award of Seismological Society of Japan for
*Extention of Mathematical Seismology* - Apr. 2022 -- Mar. 2025
- Growth and termination of dynamic rupture revealed by a stochastic fault model
- The JSPS Grant-in-Aid for Scientific Research(C) Program No. 22K03782
- Principal Investigator
- Apr. 2022 -- Mar. 2025
- Elastodynamics for strongly heterogeneous material: experiment, numerical simulation, and theory
- The JSPS Grant-in-Aid for Scientific Research(B)
- Co-Investigator
- Apr. 2021 -- Mar. 2024
- Understanding the physics of foreshocks based on dense seismic observation and seismicity model
- The JSPS Grant-in-Aid for Scientific Research(B) Program No. 21H01191
- Co-Investigator
- Apr. 2018 -- Mar. 2022
- SDE modeling for diversity and heterogeneity of earthquake ruptures
- The JSPS Grant-in-Aid for Early-Career Scientists Program No. 18K13637
- Principal Investigator
- Apr. 2017 -- Mar. 2021
- Mathematical modeling and analysis of discontinuous phenomena in continuum body
- The JSPS Grant-in-Aid for Scientific Research(B) Program No. 17H02857
- Co-Investigator

### Award

### Grants

## Contributions

- Journal Reviewer
- Bulletin of Seismological Society of America
- Computers and Mathematics with Applications
- Earth Planets Space
- European Journal of Environmental and Civil Engineering
- Geophysical Journal International
- Journal of Geophysical Research: Solid Earth
- Journal of Japan Association for Earthquake Engineering
- Tectonophysics
- Grant Reviewer
- Israel Science Foundation
- Conference Management
- Program committee for The 10th International Congress on Industrial and Applied Mathematics. Waseda University, Tokyo, Japan, August 20-25, 2023
- Organizing committee for CoMFoS18:Mathematical Analysis of Continuum Mechanics and Industrial Applications, Kyoto, Japan, June 13--15, 2018
- Projects
- Earthquake and Volcano Hazards Observation and Research Program (Co-investigator, 2015-)
- Mega Quake Risk Management project at University of Tsukuba (Postdoctoral fellow, 2013-2014)
- AE measurements in deep South African gold mines: Phase II - monitoring of rock mass damage by underground cavities and prediction of rockbursts (Research assistant, 2009-2011)

## Scientific Societies

- Geophysics
- American Geophysical Union
- Seismological Society of America
- Japan Geoscience Union
- Seismological Society of Japan
- Applied Mathematics
- The Japan Society for Industrial and Applied Mathematics (secretary of a research group Mathematical Aspects of Continuum Mechanics)