Details of the Researcher

PHOTO

Masayuki Kano
Section
Graduate School of Science
Job title
Assistant Professor
Degree

  • 博士（理学）（京都大学）

  • 修士（理学）（京都大学）

Professional Memberships 4

  • American Geophysical Union

  • JAPAN GEOSCIENCE UNION

  • The Geodetic Society of Japan

  • THE SEISMOLOGICAL SOCIETY OF JAPAN

Papers 36

  1. Data assimilation for fault slip monitoring and short-term prediction of spatio-temporal evolution of slow slip events: application to the 2010 long-term slow slip event in the Bungo Channel, Japan Peer-reviewed

    Masayuki Kano, Yusuke Tanaka, Daisuke Sato, Takeshi Iinuma, Takane Hori

    Earth, Planets and Space　76　(1)　2024/04/16

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1186/s40623-024-02004-9 　

    eISSN： 1880-5981

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    Abstract Monitoring and predicting fault slip behaviors in subduction zones is essential for understanding earthquake cycles and assessing future earthquake potential. We developed a data assimilation method for fault slip monitoring and the short-term prediction of slow slip events, and applied to the 2010 Bungo Channel slow slip event in southwest Japan. The observed geodetic data were quantitatively explained using a physics-based model with data assimilation. We investigated short-term predictability by assimilating observation data within limited periods. Without prior constraints on fault slip style, observations solely during slip acceleration predicted the occurrence of a fast slip; however, the inclusion of slip deceleration data successfully predicted a slow transient slip. With prior constraints to exclude unstable slip, the assimilation of data after slow slip event occurrence also predicted a slow transient slip. This study provides a tool using data assimilation for fault slip monitoring and prediction based on real observation data. Graphical Abstract

  2. Recent advances in earthquake seismology using machine learning Invited Peer-reviewed

    Hisahiko Kubo, Makoto Naoi, Masayuki Kano

    Earth, Planets and Space　76　(1)　2024/02/28

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1186/s40623-024-01982-0 　

    eISSN： 1880-5981

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    Abstract Given the recent developments in machine-learning technology, its application has rapidly progressed in various fields of earthquake seismology, achieving great success. Here, we review the recent advances, focusing on catalog development, seismicity analysis, ground-motion prediction, and crustal deformation analysis. First, we explore studies on the development of earthquake catalogs, including their elemental processes such as event detection/classification, arrival time picking, similar waveform searching, focal mechanism analysis, and paleoseismic record analysis. We then introduce studies related to earthquake risk evaluation and seismicity analysis. Additionally, we review studies on ground-motion prediction, which are categorized into four groups depending on whether the output is ground-motion intensity or ground-motion time series and the input is features (individual measurable properties) or time series. We discuss the effect of imbalanced ground-motion data on machine-learning models and the approaches taken to address the problem. Finally, we summarize the analysis of geodetic data related to crustal deformation, focusing on clustering analysis and detection of geodetic signals caused by seismic/aseismic phenomena. Graphical Abstract

  3. Physics‐Informed Neural Networks for Fault Slip Monitoring: Simulation, Frictional Parameter Estimation, and Prediction on Slow Slip Events in a Spring‐Slider System Peer-reviewed

    Rikuto Fukushima, Masayuki Kano, Kazuro Hirahara

    Journal of Geophysical Research: Solid Earth　128　(12)　2023/12/06

    Publisher: American Geophysical Union (AGU)

    DOI： 10.1029/2023jb027384 　

    ISSN： 2169-9313

    eISSN： 2169-9356

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    Abstract The episodic transient fault slips called slow slip events (SSEs) have been observed in many subduction zones. These slips often occur in regions adjacent to the seismogenic zone during the interseismic period, making monitoring SSEs significant for understanding large earthquakes. Various fault slip behaviors, including SSEs and earthquakes, can be explained by the spatial heterogeneity of frictional properties on the fault. Therefore, estimating frictional properties from geodetic observations and physics‐based models is crucial for fault slip monitoring. In this study, we propose a Physics‐Informed Neural Network (PINN)‐based new approach to simulate fault slip evolutions, estimate frictional parameters from observation data, and predict subsequent fault slips. PINNs, which integrate physical laws and observation data, represent the solution of physics‐based differential equations. As a first step, we validate the effectiveness of the PINN‐based approach using a simple single‐degree‐of‐freedom spring‐slider system to model SSEs. As a forward problem, we successfully reproduced the temporal evolution of SSEs using PINNs and obtained implications on how to choose the appropriate collocation points by analyzing the residuals of physics‐based differential equations. As an inverse problem, we estimated the frictional parameters from synthetic observation data and demonstrated the ability to obtain accurate values regardless of the choice of first‐guess values. Furthermore, we discussed the potential of the predictability of the subsequent fault slips using limited observation data, taking into account uncertainties. Our results indicate the significant potential of PINNs for fault slip monitoring.

  4. Potential of megathrust earthquakes along the southern Ryukyu Trench inferred from GNSS data Peer-reviewed

    Masayuki Kano, Aoi Ikeuchi, Takuya Nishimura, Shin’ichi Miyazaki, Takeshi Matsushima

    Earth, Planets and Space　73　(1)　2021/10

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1186/s40623-021-01531-z 　

    eISSN： 1880-5981

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    <title>Abstract</title>The southern part of the Ryukyu subduction zone has recorded tsunami events with a recurrence interval of several hundred years. Although their source is controversial, one model suggests that the last 1771 Yaeyama tsunami was caused by a shallow megathrust earthquake with a magnitude of 8. However, the current knowledge on interplate coupling based on recent geodetic data is limited. Here, a time series of Global Navigation Satellite System data from January 2010 to February 2021 was analyzed, including newly installed stations by Kyoto and Kyushu Universities, to obtain the distance changes between stations and vertical secular velocities. The distance changes ranged from 2.4 mm/year in contraction and to 4.7 mm/year in extension, and the vertical velocities exhibited no clear uplift or subsidence, with − 2.4 to 1.1 mm/year. The back slip inversion results indicated a slip deficit of 17–47 mm/year to the south of the Yaeyama Islands. The large slip deficit area is complementarily intervened between the shallower source area of low-frequency earthquakes and the deeper slow slip region, suggesting the spatial heterogeneity of frictional properties along the plate interface. If the large slip deficit area accumulates stress in the same rate since the last 1771 earthquake, it could result in a megathrust event with a moment magnitude greater than 7.5. Because the limited onshore data cannot resolve the slip deficit on the shallow plate interface, seafloor geodetic observations are essential to clarify the detailed spatial distribution of the slip deficit and discuss its earthquake and tsunami potential. <bold>Graphical Abstract</bold>

  5. Adjoint-based direct data assimilation of GNSS time series for optimizing frictional parameters and predicting postseismic deformation following the 2003 Tokachi-oki earthquake Peer-reviewed

    Masayuki Kano, Shin'ichi Miyazaki, Yoichi Ishikawa, Kazuro Hirahara

    Earth, Planets and Space　72　(1)　2020/12

    Publisher: Springer Science and Business Media {LLC}

    DOI： 10.1186/s40623-020-01293-0 　

    ISSN： 1880-5981

    eISSN： 1880-5981

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    <title>Abstract</title> Postseismic Global Navigation Satellite System (GNSS) time series followed by megathrust earthquakes can be interpreted as a result of afterslip on the plate interface, especially in its early phase. Afterslip is a stress release process accumulated by adjacent coseismic slip and can be considered a recovery process for future events during earthquake cycles. Spatio-temporal evolution of afterslip often triggers subsequent earthquakes through stress perturbation. Therefore, it is important to quantitatively capture the spatio-temporal evolution of afterslip and related postseismic crustal deformation and to predict their future evolution with a physics-based simulation. We developed an adjoint data assimilation method, which directly assimilates GNSS time series into a physics-based model to optimize the frictional parameters that control the slip behavior on the fault. The developed method was validated with synthetic data. Through the optimization of frictional parameters, the spatial distributions of afterslip could roughly (but not in detail) be reproduced if the observation noise was included. The optimization of frictional parameters reproduced not only the postseismic displacements used for the assimilation, but also improved the prediction skill of the following time series. Then, we applied the developed method to the observed GNSS time series for the first 15 days following the 2003 Tokachi-oki earthquake. The frictional parameters in the afterslip regions were optimized to <italic>A–B</italic> ~ <italic>O</italic>(10 kPa), <italic>A</italic> ~ <italic>O</italic>(100 kPa), and <italic>L</italic> ~ <italic>O</italic>(10 mm). A large afterslip is inferred on the shallower side of the coseismic slip area. The optimized frictional parameters quantitatively predicted the postseismic GNSS time series for the following 15 days. These characteristics can also be detected if the simulation variables can be simultaneously optimized. The developed data assimilation method, which can be directly applied to GNSS time series following megathrust earthquakes, is an effective quantitative evaluation method for assessing risks of subsequent earthquakes and for monitoring the recovery process of megathrust earthquakes.

  6. データ同化に基づく断層すべりの理解・予測と波動場推定の高度化に向けた研究 Invited Peer-reviewed

    加納将行

    地震第2輯　73　69-91　2020/07

  7. Episodic tremor and slip silently invades strongly locked megathrust in the Nankai Trough International-journal Peer-reviewed

    Masayuki Kano, Aitaro Kato, Kazushige Obara

    Scientific Reports　9　(1)　9270-9270　2019

    DOI： 10.1038/s41598-019-45781-0 　

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    Recent seismic and geodetic observations in subduction zones have revealed that slow earthquakes have preceded some large earthquakes. Characterization of slow earthquakes and their relation to large earthquakes provides important clues to constrain a wide spectrum of slip rates on tectonic faults. Here, we report new evidence of a slow slip transient at the downdip edge of the strongly locked seismogenic zone in the western Nankai Trough in southwest Japan. This slow slip transient was excited during an episodic tremor and slip at the downdip extension of the locked zone. Through this triggering, the frequent occurrence of the deep episodic tremor and slip invades the strongly locked megathrust zone and may intermittently increase the probability of large earthquakes in the Nankai Trough.

  8. Development of a Slow Earthquake Database Peer-reviewed

    Masayuki Kano, Naofumi Aso, Takanori Matsuzawa, Satoshi Ide, Satoshi Annoura, Ryuta Arai, Satoru Baba, Michael Bostock, Kevin Chao, Kosuke Heki, Satoshi Itaba, Yoshihiro Ito, Noriko Kamaya, Takuto Maeda, Julie Maury, Mamoru Nakamura, Takuya Nishimura, Koichiro Obana, Kazuaki Ohta, Natalia Poiata, Baptiste Rousset, Hiroko Sugioka, Ryota Takagi, Tsutomu Takahashi, Akiko Takeo, Yoko Tu, Naoki Uchida, Yusuke Yamashita, Kazushige Obara

    SEISMOLOGICAL RESEARCH LETTERS　89　(4)　1566-1575　2018/07

    DOI： 10.1785/0220180021 　

    ISSN： 0895-0695

    eISSN： 1938-2057

  9. Spatio-temporal Evolution of Recurrent Slow Slip Events along the Southern Ryukyu Subduction Zone, Japan, from 2010 to 2013 Peer-reviewed

    Kano, M, Fukuda, J, Miyazaki, S, Nakamura, M

    Journal of Geophysical Research: Solid Earth　123　2018

    Publisher: American Geophysical Union (AGU)

    DOI： 10.1029/2018jb016072 　

    ISSN： 2169-9313

  10. Real data assimilation for optimization of frictional parameters and prediction of afterslip in the 2003 Tokachi-oki earthquake inferred from slip velocity by an adjoint method Peer-reviewed

    Masayuki Kano, Shin'ichi Miyazaki, Yoichi Ishikawa, Yoshihisa Hiyoshi, Kosuke Ito, Kazuro Hirahara

    GEOPHYSICAL JOURNAL INTERNATIONAL　203　(1)　646-663　2015/10

    DOI： 10.1093/gji/ggv289 　

    ISSN： 0956-540X

    eISSN： 1365-246X

  11. Detecting Slow Slip Signals in Southwest Japan Based on Machine Learning Trained by Real GNSS Time Series

    Yusuke Tanaka, Masayuki Kano, Keisuke Yano

    Journal of Geophysical Research: Solid Earth　130　(2)　2025/02

    DOI： 10.1029/2024JB029499 　

    ISSN： 2169-9313

    eISSN： 2169-9356

  12. A GNSS-velocity clustering method applicable from local to global scales

    Atsushi Takahashi, Masayuki Kano, Keisuke Yano

    2024/05/28

    Publisher: Authorea, Inc.

    DOI： 10.22541/essoar.171691204.42839543/v1 　

  13. Numerical experiment toward simultaneous estimation of the spatiotemporal evolution of interseismic fault slips and block motions in southwest Japan Peer-reviewed

    Yusuke Tanaka, Masayuki Kano, Takuya Nishimura, Yusaku Ohta, Keisuke Yano

    Earth, Planets and Space　76　(69)　2024/05/08

    DOI： 10.1186/s40623-024-02009-4 　

    ISSN： 1880-5981

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    <jats:title>Abstract</jats:title><jats:p>Interseismic strain around southwest Japan can be attributed to slip phenomena on the plate interface and processes inside the continental plate, such as block motions and inland fault slips. Although many crustal deformation analyses have been carried out, the simultaneous estimation of these phenomena and comprehensive discussion regarding the effect on the total strain budget remain topics to be investigated. In this study, we conducted numerical experiment to evaluate the possibility of simultaneously monitoring the spatiotemporal evolution of interseismic fault slips and block motions based on state-space modeling. We aimed to estimate fault slips and block motions using the time series of dense continuous Global Navigation Satellite System sites covering southwest Japan, encompassing 25 years from 1996 onward. We calculated synthetic block motions of the forearc region, monotonically increasing back slips on block boundary faults, and long-term slow slip events in the Tokai region, Kii Channel, and Bungo Channel. Subsequently, we generated the expected synthetic displacement time-series at GNSS stations. Applying Kalman filtering, we successfully estimated the spatiotemporal evolution of block motions, cumulative back slips, multiple slow slip events occurring in different regions. Although the contributions of fault slips and block motions showed slight trade-off, main characteristics of the slip distributions and the direction of block motions were well-recovered. We recovered slow slip events with slips of 5–10 cm or larger. We investigated the estimation uncertainty and separation precision of the unknown parameters using the covariance matrix estimated by Kalman filtering. Focusing on the structure of the non-diagonal component of the covariance matrix, we evaluated the complex effects of site and subfault locations on the estimated slip spatial distribution bias. For instance, the extent of the correlation between subfaults suggested that the three slow slip regions have different tendency of the uncertainties of slip areas, extending toward landside, seaward, or both of them. Our framework enables the comprehensive evaluation of the contributions and uncertainties of various deformation sources covering the entire subduction zone.</jats:p> <jats:p><jats:bold>Graphical abstract</jats:bold></jats:p>

  14. Observation site selection for physical model parameter estimation toward process-driven seismic wavefield reconstruction

    K Nakai, T Nagata, K Yamada, Y Saito, T Nonomura, M Kano, S Ito, H Nagao

    Geophysical Journal International　234　(3)　1786-1805　2023/04/18

    Publisher: Oxford University Press (OUP)

    DOI： 10.1093/gji/ggad165 　

    ISSN： 0956-540X

    eISSN： 1365-246X

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    SUMMARY The ‘big’ seismic data not only acquired by seismometers but also acquired by vibrometers installed in buildings and infrastructure and accelerometers installed in smartphones will be certainly utilized for seismic research in the near future. Since it is impractical to utilize all the seismic big data in terms of the computational cost, methods which can select observation sites depending on the purpose are indispensable. We propose an observation site selection method for the accurate reconstruction of the seismic wavefield by process-driven approaches. The proposed method selects observation sites suitable for accurately estimating physical model parameters such as subsurface structures and source information to be input into a numerical simulation of the seismic wavefield. The seismic wavefield is reconstructed by the numerical simulation using the parameters estimated based on the observed signals at only observation sites selected by the proposed method. The observation site selection in the proposed method is based on the sensitivity of each observation site candidate to the physical model parameters; the matrix corresponding to the sensitivity is constructed by approximately calculating the derivatives based on the simulations, and then, observation sites are selected by evaluating the quantity of the sensitivity matrix based on the D-optimality criterion proposed in the optimal design of experiments. In this study, physical knowledge on the sensitivity to the parameters such as seismic velocity, layer thickness, and hypocentre location was obtained by investigating the characteristics of the sensitivity matrix. Furthermore, the effectiveness of the proposed method was shown by verifying the accuracy of seismic wavefield reconstruction using the observation sites selected by the proposed method.

  15. Seismic wavefield reconstruction based on compressed sensing using data-driven reduced-order model

    T Nagata, K Nakai, K Yamada, Y Saito, T Nonomura, M Kano, S Ito, H Nagao

    Geophysical Journal International　233　(1)　33-50　2022/11/29

    Publisher: Oxford University Press (OUP)

    DOI： 10.1093/gji/ggac443 　

    ISSN： 0956-540X

    eISSN： 1365-246X

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    SUMMARY Reconstruction of the distribution of ground motion due to an earthquake is one of the key technologies for the prediction of seismic damage to infrastructure. Particularly, the immediate reconstruction of the spatially continuous wavefield is valuable for decision-making of disaster response decisions in the initial phase. For a fast and accurate reconstruction, utilization of prior information is essential. In fluid mechanics, full-state recovery, which recovers the full state from sparse observation using a data-driven model reduced-order model, is actively used. In this study, the framework developed in the field of fluid mechanics is applied to seismic wavefield reconstruction. A seismic wavefield reconstruction framework based on compressed sensing using the data-driven reduced-order model (ROM) is proposed and its characteristics are investigated through numerical experiments. The data-driven ROM is generated from the data set of the wavefield using the singular value decomposition. The spatially continuous seismic wavefield is reconstructed from the sparse and discrete observation and the data-driven ROM. The observation sites used for reconstruction are effectively selected by the sensor optimization method for linear inverse problems based on a greedy algorithm. The proposed framework was applied to simulation data of theoretical waveform with the subsurface structure of the horizontally stratified three layers. The validity of the proposed method was confirmed by the reconstruction based on the noise-free observation. Since the ROM of the wavefield is used as prior information, the reconstruction error is reduced to an approximately lower error bound of the present framework, even though the number of sensors used for reconstruction is limited and randomly selected. In addition, the reconstruction error obtained by the proposed framework is much smaller than that obtained by the Gaussian process regression. For the numerical experiment with noise-contaminated observation, the reconstructed wavefield is degraded due to the observation noise, but the reconstruction error obtained by the present framework with all available observation sites is close to a lower error bound, even though the reconstructed wavefield using the Gaussian process regression is fully collapsed. Although the reconstruction error is larger than that obtained using all observation sites, the number of observation sites used for reconstruction can be reduced while minimizing the deterioration and scatter of the reconstructed data by combining it with the sensor optimization method. Hence, a better and more stable reconstruction of the wavefield than randomly selected observation sites can be realized, even if the reconstruction is carried out with a smaller number of observations with observation noise, by combining it with the sensor optimization method.

  16. A combination of tides and nontidal variations in ocean bottom pressure may generate interannual slip fluctuations in the transition zone along a subduction plate interface

    Yoshiyuki Tanaka, Hiromu Sakaue, Masayuki Kano, Suguru Yabe

    Geodesy and Geodynamics　2022/10

    Publisher: Elsevier BV

    DOI： 10.1016/j.geog.2022.09.001 　

    ISSN： 1674-9847

  17. Adjoint-based uncertainty quantification for inhomogeneous friction on a slow-slipping fault

    Shin-ichi Ito, Masayuki Kano, Hiromichi Nagao

    Geophysical Journal International　2022/09/08

    Publisher: Oxford University Press (OUP)

    DOI： 10.1093/gji/ggac354 　

    ISSN： 0956-540X

    eISSN： 1365-246X

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    Summary Long-term slow-slip events (LSSEs) usually occur on a fault existing at the deep, shallow parts of subducting plates and substantially relate to adjacent megathrust fault motions. The dynamics of the LSSE largely depend on the inhomogeneity of friction that occurs between the fault interfaces. Thus, it is crucial to estimate the spatial-dependent frictional features from the observations of the slip motion and subsequently identify essential parts that contribute to the principal slip motion by quantifying uncertainties involved in the estimates. Although quantifying the uncertainties of the frictional feature fields in high-resolution is necessary to solve the task, conventional techniques of quantifying slow earthquake frictional features have not yet achieved such uncertainty quantification (UQ) due to the complexity of LSSE models such as the large dimensionality. We, therefore, propose a method of UQ for spatially inhomogeneous frictional features from slip motion based on a four-dimensional variational data assimilation technique using a second-order adjoint method. The proposed method enables us to conduct an accurate UQ even when the dimensionality is large. By combining a fault motion model that mimics slow-slip motion on an LSSE fault—megathrust fault complex in southwestern Japan and the data assimilation technique, we successfully quantified the spatial distribution of the uncertainty of the frictional features in high-resolution. The evaluated spatial distribution in high-resolution reveals the correlation between the dynamics of the slow-slip motion and the important components of the frictional features, which is valuable information for design of observation systems. Findings from this study are expected to advance the theoretical foundation of applied seismic motion prediction techniques using slow-slip frictional features as stress meters for megaquakes, as well as improve understanding of the relationship between the slow-slip motion and frictional parameters of a fault.

  18. l(1) Trend Filtering-Based Detection of Short-Term Slow Slip Events: Application to a GNSS Array in Southwest Japan

    Keisuke Yano, Masayuki Kano

    JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH　127　(5)　2022/05

    DOI： 10.1029/2021JB023258 　

    ISSN： 2169-9313

    eISSN： 2169-9356

  19. Bayesian-based joint determination of earthquake hypocentres and 1-D velocity structures divided by a structural boundary Peer-reviewed

    Takahiro Shiina, Masayuki Kano

    Geophysical Journal International　230　(2)　759-775　2022/04/13

    Publisher: Oxford University Press ({OUP})

    DOI： 10.1093/gji/ggac065 　

    ISSN： 0956-540X 1365-246X

    eISSN： 1365-246X

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    Summary We propose a Bayesian approach for jointly determining the locations of earthquake hypocenters and velocity structures in a region divided by a structural boundary, such as a fault zone. To accommodate the Markov chain Monte Carlo (MCMC) method in a region containing lateral velocity contrast, we incorporated a data-driven station clustering scheme when estimating earthquake hypocenter locations, a one-dimensional (1-D) velocity model assigned to each cluster, and station corrections for travel times. The proposed method realises the clustering of stations reflecting velocity structures beneath the station network in the framework of the MCMC method. We verified the performances of the proposed method using numerical experiments with different distributions of earthquake hypocenters relative to the structural boundary. The results demonstrated that the proposed method reconstructed earthquake hypocenter locations and velocity structures involving lateral contrast robustly to earthquake distributions. Additionally, the number of 1-D velocity models (the number of station clusters) was optimised by comparing resultant posterior probability proportional to distances between the observed and theoretical travel times. We also applied the proposed method to estimate the earthquake hypocenter locations and velocity structures around the source area of the 2004 Mid-Niigata prefecture earthquake, Japan, to examine the applicability of the proposed method to real observation data. The stations were divided into east and west clusters, coinciding with the lateral velocity variation related to the geological setting. Therefore, the proposed method accurately determines earthquake hypocenters in a region divided by a structural boundary without any knowledge regarding the geological structure.

  20. A convolutional neural network-based classification of local earthquakes and tectonic tremors in Sanriku-oki, Japan, using S-net data Peer-reviewed

    Hidenobu Takahashi, Kazuya Tateiwa, Keisuke Yano, Masayuki Kano

    Earth, Planets and Space　73　(1)　2021/10

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1186/s40623-021-01524-y 　

    eISSN： 1880-5981

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    <title>Abstract</title>Low-frequency tremors have been widely detected in many tectonic zones, and are often located adjacent to megathrust zones, indicating that their spatiotemporal evolution provides important insights into megathrust events. The envelope correlation method (ECM) is commonly used to detect tremors. However, the ECM also detects regular earthquakes, which requires the separation of these two signals after the initial detection. In addition, signals of tremors are weak, so classifying tremors from noises is also an essential problem. We develop a convolutional neural network (CNN)-based method using a single S-net station located off Sanriku region, Northeast Japan, to classify local earthquakes, tremors, and noise. Along the Japan Trench, especially in a region focused in this study, local earthquakes and tremors occurred in coexistence within a small region, so detection, location, and discrimination of these events are the key to understand the relationship between slow and regular earthquakes. The spectrograms of the three-component velocity waveforms that were recorded during 16 August 2016 to 14 August 2018 are used as the training and test datasets for the CNN. The CNN successfully classified 100%, 96%, and 98% of the earthquakes, tremors, and noise, respectively. We also showed a successful application of our method to continuous waveform data including a tremor to explore the feasibility of the proposed method in classifying tremors and noise in continuous streaming data. The output probabilities for the true classifications decrease with increasing epicentral distance and/or decreasing event magnitude. This highlights the need to train the CNN using tremors proximal to the seismic stations for detecting tremors using multiple stations.

  21. Spatial changes in inclusion band spacing as an indicator of temporal changes in slow slip and tremor recurrence intervals Peer-reviewed

    Naoki Nishiyama, Kohtaro Ujiie, Masayuki Kano

    Earth, Planets and Space　73　(1)　2021/06

    Publisher: Springer Science and Business Media LLC

    DOI： 10.1186/s40623-021-01448-7 　

    eISSN： 1880-5981

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    <title>Abstract</title>Slow slip and tremor (SST) downdip of the seismogenic zones may trigger megathrust earthquakes by frequently transferring stress to seismogenic zones. Geodetic observations have suggested that the recurrence intervals of slow slip decrease toward the next megathrust earthquake. However, temporal variations in the recurrence intervals of SST during megathrust earthquake cycles remain poorly understood because of the limited duration of geodetic and seismological monitoring of slow earthquakes. The quartz-filled, crack-seal shear veins in the subduction mélange deformed near the downdip limit of the seismogenic zone in warm-slab environments record cyclic changes in the inclusion band spacing in the range from 4 ± 1 to 65 ± 18 μm. The two-phase primary fluid inclusions in quartz between inclusion bands exhibit varying vapor/liquid ratios regardless of inclusion band spacing, suggesting a common occurrence of fast quartz sealing due to a rapid decrease in quartz solubility associated with a large fluid pressure reduction. A kinetic model of quartz precipitation, considering a large fluid pressure change and inclusion band spacing, indicates that the sealing time during a single crack-seal event cyclically decreased and increased in the range from 0.16 ± 0.04 to 2.7 ± 0.8 years, with one cycle lasting at least 27 ± 2 to 93 ± 5 years. The ranges of sealing time and duration of a cycle may be comparable to the recurrence intervals of SST and megathrust earthquakes, respectively. We suggest that the spatial change in inclusion band spacing is a potential geological indicator of temporal changes in SST recurrence intervals, particularly when large fluid pressure reduction occurs by brittle fracturing.

  22. An Optimum 2D Seismic-Wavefield Reconstruction in Densely and Nonuniformly Distributed Stations: The Metropolitan Seismic Observation Network in Japan Peer-reviewed

    Takahiro Shiina, Takuto Maeda, Masayuki Kano, Aitaro Kato, Naoshi Hirata

    Seismological Research Letters　92　(3)　2015-2027　2021/05/01

    Publisher: Seismological Society of America ({SSA})

    DOI： 10.1785/0220200196 　

    ISSN： 0895-0695 1938-2057

    eISSN： 1938-2057

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    <title>Abstract</title> We propose an optimization method for applying the seismic-wave gradiometry (SWG) method to a dense seismic station network consisting of nonuniformly distributed seismographs. As a nonuniformly distributed station array, we consider the station layout of the Metropolitan Seismic Observation Network (MeSO-net) operated in and around the Tokyo metropolitan area, Japan. In this study, thereby, we numerically investigate optimum shapes of weighting functions, which control the spatial weights of individual stations when estimating waveforms at any grid points in the SWG method, to reconstruct seismic wavefields propagating in the MeSO-net. The functions with isotropic spatial weights are found to be appropriate for wavefield reconstructions with seismic waves incoming from practically all directions, even for nonuniformly distributed stations. The reproducibility of the wavefields is greatly improved by changing the shapes of the spatial weights reflecting density of the stations. Further plausible wavefield reconstructions are made by considering the propagation directions of the seismic waves. In these cases, if the weight of a contribution for a wavefield reconstruction is larger at far stations with a direction perpendicular to the wave propagation direction, then the reproducibility of the waveforms is significantly increased. In addition, the spatial gradients of the amplitudes are well reproduced by the optimized SWG method even though the optimization only focused on the amplitudes. Therefore, our proposed optimization scheme can be used to accurately estimate seismic wavefields in a nonuniformly distributed station array. Actually, the weighting functions optimized in this study succeeded to reconstruct the seismic wavefield of a shallow crustal earthquake that occurred around the Tokyo metropolitan area, based on the observed seismograms obtained by the MeSO-net.

  23. Detailed Spatial Slip Distribution for Short‐Term Slow Slip Events Along the Nankai Subduction Zone, Southwest Japan Peer-reviewed

    Masayuki Kano, Aitaro Kato

    Journal of Geophysical Research: Solid Earth　125　(7)　2020/07

    Publisher: American Geophysical Union (AGU)

    DOI： 10.1029/2020jb019613 　

    ISSN： 2169-9313

    eISSN： 2169-9356

  24. Capture of eruption column used by GPS: the Sakurajima eruption on August 18, 2013

    Asakura Yukako, Nishimura Takeshi, Ohta Yusaku, Kano Masayuki, Iguchi Masato

    PROGRAMME AND ABSTRACTS THE VOLCANOLOGICAL SOCIETY OF JAPAN　2020　40-40　2020

    Publisher: The Volcanological Society of Japan

    DOI： 10.18940/vsj.2020.0_40 　

    ISSN： 2433-5320

    eISSN： 2189-7190

  25. Possible slow slip event beneath the Kii Peninsula, southwest Japan, inferred from historical tilt records in 1973 Peer-reviewed

    Masayuki Kano

    Earth, Planets and Space　71-95　2019/07

    DOI： 10.1186/s40623-019-1076-9 　

    ISSN： 1880-5981

  26. スロー地震データベースの構築

    加納将行・麻生尚文・松澤孝紀・井出哲・小原一成

    地震予知連絡会会報　100　2019

  27. Strength of tremor patches along deep transition zone of a megathrust International-journal Peer-reviewed

    Masayuki Kano, Aitaro Kato, Ryosuke Ando, Kazushige Obara

    Scientific Reports　8　(1)　3655-3655　2018

    DOI： 10.1038/s41598-018-22048-8 　

    More details Close

    Deep low frequency tremors are indicators of slow slip transients in the brittle-ductile transition zone along subducting plates. Investigation of comprehensive tremor activities is therefore an important issue for understanding the seismic/aseismic characteristics in transition zones. Here, we focus on the radiated energy from tremors to reveal the along-strike heterogeneity in the strength of tremor patches. Based on a tremor catalog that more accurately evaluates radiated energy, we examine the spatio-temporal activity of tremors accompanied by slow slip events (SSEs) in western Shikoku, southwestern Japan. The new finding of this study is that the energy radiated from tremors is positively correlated with the speed of tremor migration front and the slip rate along the plate interface during a SSE. This can be qualitatively explained by a stress diffusion model, which consists of along-strike heterogeneities in the effective strength of tremor patches embedded in a ductile shear zone. This effective strength heterogeneity is supported by a lateral variation in the stress drop of a SSE; it is consistent with the fluid pressure distribution along the plate boundary fault and the tidal sensitivity of tremors. Accurate evaluation of tremor activities, especially the radiated energy, can be used to infer the spatial distribution of the strength of tremor patches in transition zones worldwide.

  28. Diffusion creep and grain growth in forsterite +20 vol% enstatite aggregates: 1. High‐resolution experiments and their data analyses Peer-reviewed

    Tadashi Nakakoji, Takehiko Hiraga, Hiromichi Nagao, Shin-ichi Ito, Masayuki Kano

    Journal of Geophysical Research: Solid Earth　123　(11)　9486-9512　2018

    DOI： 10.1029/2018JB015818 　

    ISSN： 2169-9313

    eISSN： 2169-9356

  29. Seismic wavefield imaging of long-period ground motion in the Tokyo metropolitan area, Japan Peer-reviewed

    M. Kano, H. Nagao, K. Nagata, S. Ito, S. Sakai, S. Nakagawa, M. Hori, N. Hirata

    JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH　122　(7)　5435-5451　2017/07

    DOI： 10.1002/2017JB014276 　

    ISSN： 2169-9313

    eISSN： 2169-9356

  30. スパースモデリングとの融合によるデータ駆動科学の新展開

    長尾大道, 伊藤伸一, 加納将行

    61　(4)　132-137　2017

    Publisher:

    DOI： 10.11509/isciesci.61.4_132 　

    ISSN： 0916-1600

  31. 大規模自由度系におけるデータ同化のための2nd-order adjoint法に基づく不確実性評価法

    伊藤伸一, 長尾大道, 山中晃徳, 塚田祐貴, 小山敏幸, 加納将行, 井上純哉

    59　(59)　76-82　2017

    Publisher:

    ISSN： 0916-8575

  32. Seismic wavefield imaging based on the replica exchange Monte Carlo method Peer-reviewed

    Masayuki Kano, Hiromichi Nagao, Daichi Ishikawa, Shin-ichi Ito, Shin'ichi Sakai, Shigeki Nakagawa, Muneo Hori, Naoshi Hirata

    GEOPHYSICAL JOURNAL INTERNATIONAL　208　(1)　529-545　2017/01

    DOI： 10.1093/gji/ggw410 　

    ISSN： 0956-540X

    eISSN： 1365-246X

  33. Data assimilation for massive autonomous systems based on a second-order adjoint method Peer-reviewed

    Shin-ichi Ito, Hiromichi Nagao, Akinori Yamanaka, Yuhki Tsukada, Toshiyuki Koyama, Masayuki Kano, Junya Inoue

    PHYSICAL REVIEW E　94　(4)　2016/10

    DOI： 10.1103/PhysRevE.94.043307 　

    ISSN： 2470-0045

    eISSN： 2470-0053

  34. Azimuth verification of the MeSO-net seismographs Peer-reviewed

    Masayuki Kano, Hiromichi Nagao, Katsuhiko Shiomi, Shin’ichi Sakai, Shigeki Nakagawa, Ryo Honda, Sadanobu Mizusako, Muneo Hori, Naoshi Hirata

    Zisin 2　68　(2)　31-44　2015

    Publisher: SEISMOLOGICAL SOCIETY OF JAPAN

    DOI： 10.4294/zisin.68.31 　

    ISSN： 0037-1114

    More details Close

    The dense seismic array "MeSO-net" (Metropolitan Seismic Observation network), in which 296 accelerometers, at this moment, are installed with several kilometer intervals, was established in 2007 for the purpose of the disaster mitigation for forthcoming large earthquakes. Whether the actual azimuths of MeSO-net seismometers newly installed after 2009 were really in the magnetic north or not has not been verified yet, while the azimuths of three seismometers installed before 2008 were already confirmed to be in the opposite direction. Since such obvious errors in the azimuths badly affect subsequent data processing, we evaluate the azimuths of all seismometers based on cross-correlations with seismograms recorded at nearby Hi-net tiltmeters and F-net broadband seismometers. Our result suggests that the northward components at more than 80% of stations are determined to be within 10 degrees from the magnetic north, while those at the three stations are reconfirmed to rotate more than 90 degrees as the previous study pointed out. Correcting azimuths of all seismograms based on the result, the estimated coherence is clearly improved in the frequency band less than 0.10Hz.

  35. An adjoint data assimilation method for optimizing frictional parameters on the afterslip area Peer-reviewed

    Masayuki Kano, Shin'ichi Miyazaki, Kosuke Ito, Kazuro Hirahara

    EARTH PLANETS AND SPACE　65　(12)　1575-1580　2013

    DOI： 10.5047/eps.2013.08.002 　

    ISSN： 1880-5981

  36. Estimation of frictional parameters and initial values of simulation variables using an adjoint data assimilation method with synthetic afterslip data Peer-reviewed

    Masayuki Kano, Shin'ichi Miyazaki, Kosuke Ito, Kazuro Hirahara

    Zisin 2　63　(2)　57-69　2010

    Publisher:

    DOI： 10.4294/zisin.63.57 　

    ISSN： 0037-1114

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Misc. 14

  1. MCMC-based joint determination of earthquake hypocenters and 1-D velocity structures around a fault zone

    椎名高裕, 加納将行

    日本地球惑星科学連合大会予稿集(Web)　2021　2021

  2. Estimation of depth-dependent variations in seismic velocity in the source area of the 2004 Mid-Niigata prefecture earthquake based on the MCMC approach

    椎名高裕, 加納将行, 倉田澄人, 加藤愛太郎

    日本地震学会秋季大会講演予稿集(CD-ROM)　2021　2021

  3. 不均質な観測点配置における地震波動場の推定:首都圏地震観測網への適用

    椎名高裕, 前田拓人, 加納将行, 加藤愛太郎, 平田直, 平田直

    統計関連学会連合大会講演報告集　2020　2020

  4. スロー地震カタログの標準化に向けて-データベースの整備-

    加納将行, 麻生尚文, 案浦理, 新井隆太, 伊藤喜宏, 鎌谷紀子, MAURY Julie, 中村衛, 西村卓也, 尾鼻浩一郎, 杉岡裕子, 高木涼太, 高橋努, 竹尾明子, 山下裕亮, 松澤孝紀, 井出哲, 小原一成

    日本地震学会秋季大会講演予稿集(CD-ROM)　2017　2017

  5. レプリカ交換モンテカルロ法を用いた首都圏地震動イメージング

    加納将行, 長尾大道, 伊藤伸一, 石川大智, 酒井慎一, 中川茂樹, 堀宗朗, 平田直

    日本地震学会秋季大会講演予稿集　2016　2016

  6. レプリカ交換モンテカルロ法に基づく首都圏地震動イメージング

    加納将行, 長尾大道, 伊藤伸一, 酒井慎一, 中川茂樹, 堀宗朗, 平田直, 石川大智

    統計関連学会連合大会講演報告集　2016　2016

  7. 都市の脆弱性が引き起こす激甚災害の軽減化プロジェクト:1)首都直下地震の地震ハザード・リスク予測のための調査・研究

    平田直, 中川茂樹, 酒井慎一, 鶴岡弘, 佐藤比呂志, 佐竹健治, 木村尚紀, 本多亮, 堀宗朗, 長尾大道, 石辺岳男, 村岸純, 加納将行, 中村亮一, PANAYOTOPOULOS Yannis, 横井佐代子

    日本地球惑星科学連合大会予稿集(Web)　2016　2016

  8. 首都圏地震動イメージング

    長尾大道, 加納将行, 堀宗朗, 酒井慎一, 中川茂樹, 平田直, 水迫覚信, 廣瀬慧, 本多亮, 木村尚紀

    統計関連学会連合大会講演報告集　2015　2015

  9. 首都圏地震動イメージング:水平成層構造の解析解を用いた手法の検証

    加納将行, 長尾大道, 石川大智, 酒井慎一, 中川茂樹, 本多亮, 木村尚紀, 堀宗朗, 平田直

    日本地震学会秋季大会講演予稿集　2015　2015

  10. Development of Computational Techniques for Large-Scale Data Assimilation

    NAGAO Hiromichi, ITO Shin-ichi, KANO Masayuki, ISHIKAWA Daichi

    The Proceedings of The Computational Mechanics Conference　2015　(0)　_152-1_-_152-2_　2015

    Publisher: The Japan Society of Mechanical Engineers

    ISSN： 1348-026X

    More details Close

    Data assimilation (DA), which is fundamental computational technique to integrate numerical simulations model and observation data, has been applied in various fields of science. Reducing computational cost and/or memory usage are always key issues when DA is applied to a large-scale numerical simulation model. DA using an ensemble-based sequential Bayesian filter, e.g., the ensemble Kalman filter or the particle filter, easily faces to an endless computation since it usually requires several tens, hundreds or more times as much computational cost as one-time simulation does. We demonstrate the efficiency of the adjoint method by applying to the phase field model, which is capable of explaining the movement of phase boundary due to formation of composition

  11. Estimation of frictional parameters in the afterslip areas by an adjoint data assimilation method

    Kano Masayuki, Ishikawa Yoichi, Hiyoshi Yoshihisa, Ito Kosuke, Hirahara Kazuro

    The Computational Mechanics Conference　2014　(27)　206-207　2014/11/22

    Publisher: The Japan Society of Mechanical Engineers

    ISSN： 1348-026X

  12. 高空間分解能を持つ地震動分布を推定するためのアルゴリズム開発

    長尾大道, 水迫覚信, 加納将行, 堀宗朗, 廣瀬慧

    統計関連学会連合大会講演報告集　2014　2014

  13. 首都圏地震観測網MeSO-net加速度計の設置方位の検証

    加納将行, 長尾大道, 汐見勝彦, 酒井慎一, 中川茂樹, 水迫覚信, 堀宗朗, 平田直

    日本地震学会秋季大会講演予稿集　2014　2014

  14. 高空間分解能地震動分布を推定するためのアルゴリズム開発

    長尾大道, 水迫覚信, 加納将行, 堀宗朗, 廣瀬慧

    理論応用力学講演会講演論文集(Web)　63rd　2014

Show all ︎Show first 5

Presentations 66

  1. 西南日本で発生する短期的スロースリップイベントの累積すべり分布の推定

    加納将行, 加藤愛太郎

    日本測地学会第134回講演会　2020/10/22

  2. Physics-Informed Neural Networks for Data assimilation in a model of Slow Slip Events with spatially variable friction

    Rikuto Fukushima, Masayuki Kano, Kazuro Hirahara, Makiko Ohtani, Kyungjae Im, Jean-Philippe Avouac

    2024 AGU Fall Meeting　2024/12

  3. アジョイント法に基づく2003年十勝沖地震の余効すべりの現状把握と短期推移予測

    加納将行, 宮崎真一, 石川洋一, 平原和朗

    日本測地学会第136回講演会　2021/11

  4. l1トレンドフィルタリングによる西南日本GNSSアレイからの短期スロースリップ現象の検出

    矢野恵佑, 加納将行

    日本測地学会第136回講演会　2021/11

  5. l1トレンドフィルタリングによる西南日本GNSSアレイからの短期スロースリップ現象の検出

    2021/10

  6. アジョイント法に基づく2003年十勝沖地震の余効すべりの現状把握と短期推移予測

    2021/10

  7. MCMC法を用いた2004年新潟県中越地震震源域周辺の地震波速度分布の推定

    2021/10

  8. Spatial changes in inclusion band spacing as an indicator of temporal changes in slow earthquake recurrence intervals

    Naoki Nishiyama, Kohtaro Ujiie, Masayuki Kano

    2021/09

  9. Spatial changes in inclusion band spacing as an indicator of temporal changes in slow earthquake recurrence intervals

    Naoki Nishiyama, Kohtaro Ujiie, Masayuki Kano

    International Joint Workshop on Slow Earthquakes 2021　2021/09

  10. Possible chaotic behaviour of deep VLFEs during long-term SSE revealed by the comprehensive automatic detection of VLFEs

    Akiko Takeo, Masayuki Kano, Takahiro Hatano, Kazushige Obara

    International Joint Workshop on Slow Earthquakes 2021　2021/09

  11. Adjoint-based Uncertainty Quantification of Frictional Inhomogeneity on Slow-slipping Fault

    Shin-ichi Ito, Masayuki Kano, Hiromichi Nagao

    AOGS 2021 virtual　2021/07

  12. Adjoint-based uncertainty quantification of frictional inhomogeneity on slow-slipping fault

    伊藤伸一, 加納将行, 長尾大道

    日本地球惑星科学連合大会2021年大会　2021/06

  13. スパース観測による地震波動場再構成に向けたセンサー選択 (第二報: データ駆動型低次元モデルに基づく手法に関する初期検討)

    永田貴之, 中井公美, 齋藤勇士, 野々村拓, 加納将行, 伊藤伸一, 長尾大道

    日本地球惑星科学連合大会2021年大会　2021/06

  14. S-net単独観測点を用いたCNNによる三陸沖の近地地震・微動の分類とその汎用性の評価

    加納将行, 高橋秀暢, 立岩和也, 矢野恵佑

    日本地球惑星科学連合大会2021年大会　2021/06

  15. GNSSデータを用いた八重山諸島における平均変位速度ベクトルの推定

    池内葵, 加納将行, 中原恒, 西村太志, 駒野和基, 西村卓也, 宮崎真一

    日本地球惑星科学連合大会2021年大会　2021/06

  16. GNSSを用いた短期的スロースリップイベントの自動検出：l1トレンドフィルタリングを用いたアプローチ

    矢野恵佑, 加納将行

    日本地球惑星科学連合大会2021年大会　2021/06

  17. スパース観測による地震波動場再構成に向けたセンサー選択 (第一報: 支配方程式の線形化モデルに基づく手法の提案とその評価)

    中井公美, 永田貴之, 齋藤勇士, 野々村拓, 加納将行, 伊藤伸一, 長尾大道

    日本地球惑星科学連合大会2021年大会　2021/06

  18. MCMC法を用いた断層域近傍における地震震源と１次元速度構造の同時推定

    椎名高裕, 加納将行

    日本地球惑星科学連合大会2021年大会　2021/06

  19. Spatial changes in inclusion band spacing as an indicator of temporal changes in slow earthquake recurrence intervals

    Naoki Nishiyama, Kohtaro Ujiie, Masayuki Kano

    EGU General Assembly 2021　2021/04

  20. GNSSを用いた短期的スロースリップイベントの自動検出：l1トレンドフィルタリングを用いたアプローチ

    矢野恵佑, 加納将行

    「AI×地震の今と未来」研究集会　2021/03/11

  21. S-net単独観測点を用いたCNNによる三陸沖の近地地震・微動の分類とその汎用性の評価

    加納将行, 高橋秀暢, 立岩和也, 矢野恵佑

    「AI×地震の今と未来」研究集会　2021/03/11

  22. Detailed spatial slip distribution for short-term slow slip events and the spatial relation to megathrusts along the Nankai subduction zone, southwest Japan Invited

    Masayuki Kano, Aitaro Kato, Kazushige Obara

    2020 AGU Fall Meeting　2020/12

  23. S-netを用いた畳み込みニューラルネットによる三陸沖低周波微動検出の試み

    矢野恵佑, 高橋秀暢, 立岩和也, 加納将行

    日本地震学会2020年度秋季大会　2020/10/31

  24. GNSS複数観測点からの短期的スロースリップの自動検出：トレンドフィルタリングを用いたアプローチ

    矢野恵佑, 加納将行

    日本地震学会2020年度秋季大会　2020/10/30

  25. 琉球弧南西部で発生する SSE に関するすべり時空間発展の解析

    駒野和基, 宮崎真一, 加納将行, 松島健, 西村卓也

    日本測地学会第134回講演会　2020/10/22

  26. 東海地方の深部短期スロースリップイベント発生時期における駿河トラフ上盤－下盤間のGNSS基線長変化西南日本で発生する短期的スロースリップイベントの累積すべり分布の推定

    三井雄太, 加納将行

    日本測地学会第134回講演会　2020/10/22

  27. トレンドフィルタリングを用いたGNSS観測点からの短期的スロースリップの自動検出

    矢野恵佑, 加納将行

    日本測地学会第134回講演会　2020/10/22

  28. GPS 搬送波位相遅延量を利用した噴煙検知 −2013 年 8 月 18 日桜島噴火の解析−

    朝倉由香子, 西村太志, 太田雄策, 加納将行, 井口正人

    2020年度日本火山学会秋季大会　2020/10

  29. Spatial and temporal relation between slow and large earthquakes: inference from crustal deformation data

    Masayuki Kano

    Slow Earthquakes WS 2020 Virtual　2020/09

  30. 複数観測点を用いたスロースリップイベントの自動検知

    矢野恵佑, 加納将行

    2020年度統計関連学会連合大会　2020/09

  31. 変分法データ同化に基づく断層すべり面の摩擦特性空間分布の不確実性評価 Invited

    伊藤伸一, 加納将行, 長尾大道

    2020年度統計関連学会連合大会　2020/09

  32. 不均質な観測点配置における地震波動場の推定：首都圏地震観測網への適用 Invited

    椎名高裕, 前田拓人, 加納将行, 加藤愛太郎, 平田直

    2020年度統計関連学会連合大会　2020/09

  33. Can crack-seal veins record recurrence intervals of slow earthquakes?

    Naoki Nishiyama, Kohtaro Ujiie, Masayuki Kano

    JpGU-AGU Joint Meeting 2020　2020/07

  34. 桜島の噴火に伴うGPS衛星電波の搬送波位相遅延量の変化－2013年から2019年のデータ解析－

    朝倉由香子, 西村太志, 太田雄策, 加納将行

    JpGU-AGU Joint Meeting 2020　2020/07

  35. Twin Experiment of 4DVar Capable of Uncertainty Quantification Based on Seismic Wavefield Propagation

    Hiromichi Nagao, Shin-ichi Ito, Masayuki Kano, Mitsuru Matsumura

    JpGU-AGU Joint Meeting 2020　2020/07

  36. Uncertainty Quantification for Inhomogeneous Frictional Features in a Slow-Slipping Fault Based on a Large-Scale Four-Dimensional Variational Data Assimilation

    Shin-ichi Ito, Masayuki Kano, Hiromichi Nagao

    JpGU-AGU Joint Meeting 2020　2020/07

  37. An application of reversible-jump MCMC method for simultaneous determinations of 1-D velocity structures and hypocenters around a fault (II): Synthetic analyses

    Takahiro Shiina, Masayuki Kano

    JpGU-AGU Joint Meeting 2020　2020/07

  38. An application of reversible-jump MCMC method for simultaneous determinations of 1-D velocity structures and hypocenters around a fault (I): Formulation

    Masayuki Kano, Takahiro Shiina

    JpGU-AGU Joint Meeting 2020　2020/07

  39. 新設されたGNSS観測点を用いた琉球弧南西部で発生するSSEに関するすべり時空間発展解析

    駒野和基, 宮崎真一, 加納将行, 松島健, 西村卓也

    JpGU-AGU Joint Meeting 2020　2020/07

  40. Detailed Spatial Slip Distribution for Short-term Slow Slip Events along the Nankai Subduction Zone

    Masayuki Kano, Aitaro Kato

    JpGU-AGU Joint Meeting 2020　2020/07

  41. ベイズ l1 トレンドフィルタリングに基づくスロースリップ自動検知法

    矢野恵佑, 加納将行

    JpGU-AGU Joint Meeting 2020　2020/07/12

  42. Implementation of Replica Exchange Monte Carlo on 4DVar for Global Optimization

    2019 AGU Fall Meeting　2019/12

  43. Uncertainty quantification for inhomogeneous frictional features in a slow-slipping fault based on a large-scale four-dimensional variational data assimilation

    Shin-ichi Ito, Masayuki Kano, Hiromichi Nagao

    2019 AGU Fall Meeting　2019/12

  44. 四国西部の深部短期的ＳＳＥに同期して固着域下端で発生するゆっくりすべり

    加納 将行, 加藤愛太郎, 小原一成

    日本測地学会第132回講演会　2019/10

  45. 大規模４次元変分法データ同化に基づくスロースリップ断層面における摩擦特性不均一性の不確実性評価

    2019/09

  46. 「スロー地震データベース」の取り組み

    松澤孝紀, 加納将行, 田中優作, 麻生尚文, 井出哲, 小原一成

    日本地震学会2019年度秋季大会　2019/09

  47. データ同化に基づく断層すべりの理解・予測と波動場推定の高度化に向けた研究 Invited

    加納 将行

    日本地震学会2019年度秋季大会　2019/09/16

  48. Episodic tremor and slip silently invades strongly locked megathrust in the Nankai Trough International-presentation

    Masayuki Kano, Aitaro Kato, Kazushige Obara

    Joint Workshop on Slow Earthquakes 2019　2019/09

  49. Uncertainty quantification based on 4DVar data assimilation for massive simulation models

    Shin-ichi Ito, Masayuki Kano, Hiromichi Nagao

    11th International Workshop on Statistical Seismology (StatSei11)　2019/08/18

  50. An optimization for estimating seismic wavefields in MeSO-net

    Takahiro Shiina, Takuto Maeda, Masayuki Kano, Aitaro Kato, Naoshi Hirata

    11th International Workshop on Statistical Seismology (StatSei11)　2019/08/18

  51. Reanalysis of old ground tilt data recorded at Kii Peninsula, southwest Japan

    Yasuyuki Kano, Masayuki Kano

    IUGG 2019　2019/07

  52. Episodic tremor and slip silently invades strongly locked megathrust in the Nankai Trough International-presentation

    Masayuki Kano, Aitaro Kato, Kazushige Obara

    IUGG 2019　2019/07

  53. Uncertainty quantification based on 4DVar data assimilation for massive simulation models

    2019/05

  54. 稠密地震観測網における地震波動場の推定：MeSO-netにおける最適化

    椎名高裕, 前田拓人, 加納将行, 加藤愛太郎, 平田直

    日本地球惑星科学連合大会2019年大会　2019/05

  55. Episodic tremor and slip silently invades strongly locked megathrust in the Nankai Trough

    Masayuki Kano, Aitaro Kato, Kazushige Obara

    2019/05

  56. Seismic wavefield imaging based on dense seismic networks using replica exchange Monte Carlo method

    Masayuki Kano, Hiromichi Nagao, Kenji Nagata, Shin-ichi Ito, Kei Hasegawa, Shin’ichi Sakai, Shigeki Nakagawa, Muneo Hori, Naoshi Hirata

    2019/05

  57. 1970年代の傾斜記録に基づく紀伊半島でのスロースリップイベントの可能性

    加納 将行, 加納 靖之

    日本地球惑星科学連合大会2019年大会　2019/05

  58. 琉球海溝南西部で繰り返し発生するSSEのすべりの時空間発展の多様性

    加納将行, 福田淳一, 宮崎真一, 中村衛

    日本測地学会第130回講演会　2018/10

  59. アジョイント法によるSSE発生域の摩擦特性の推定

    加納将行, 宮崎真一, 平原和朗

    日本地震学会2018年度秋季大会　2018/10

  60. Temporal variation of SSEs in the southern Ryukyu subduction zone: Implications for frictional parameters on the fault International-presentation

    Masayuki Kano, Jun’ichi Fukuda, Shin’ichi Miyazaki, Mamoru Nakamura

    Joint Workshop on Slow Earthquakes 2018　2018/09

  61. Strength of tremor patches along deep transition zone of a megathrust International-presentation

    Masayuki Kano, Aitaro Kato, Ryosuke Ando, Kazushige Obara

    AOGS 2018　2018/06/07

  62. Seismic wavefield imaging of long-period ground motion in the Tokyo metropolitan area, Japan International-presentation

    Masayuki Kano, Hiromichi Nagao, Kenji Nagata, Shin-ichi Ito, Shin’ichi Sakai, Shigeki Nakagawa, Muneo Hori, Naoshi Hirata

    AOGS 2018　2018/06/06

  63. Strength of tremor patches along deep transition zone of a megathrust

    Masayuki Kano, Aitaro Kato, Ryosuke Ando, Kazushige Obara

    JpGU 2018　2018/05/23

  64. Development of Slow Earthquake Database

    Masayuki Kano, Naofumi Aso, Takanori Matsuzawa, Satoshi Ide, Satoshi Annoura, Ryuta Arai, Satoru Baba, Michael Bostock, Kevin Chao, Kosuke Heki, Satoshi Itaba, Yoshihiro Ito, Noriko Kamaya, Takuto Maeda, Julie Maury, Mamoru Nakamura, Takuya Nishimura, Koichiro Obana, Kazuaki Ohta, Natalia Poiata, Baptiste Rousset, Hiroko Sugioka, Ryota Takagi, Tsutomu Takahashi, Akiko Takeo, Yoko Tu, Naoki Uchida, Yusuke Yamashita, Kazushige Obara

    JpGU 2018　2018/05/23

  65. Seismic Wavefield Imaging of Long-Period Ground Motion in the Tokyo Metropolitan Area, Japan

    Masayuki Kano, Hiromichi Nagao, Kenji Nagata, Shin-ichi Ito, Shin’ichi Sakai, Shigeki Nakagawa, Muneo Hori, Naoshi Hirata

    JpGU 2018　2018/05/22

  66. 地殻変動データから示唆されるSSEと巨大地震の時空間的関連性

    加納将行

    「スロー地震学」A01/A02班合同研究集会　2020/06

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Research Projects 6

  1. Mathematical Foundation for Seismic Modeling Pioneered by Information Statistics

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (A)

    Institution: The University of Tokyo

    2023/04/01 - 2028/03/31

  2. 浅部スロースリップイベントはデータ同化でどの程度予測できるのか？

    加納 将行

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 学術変革領域研究(A)

    Institution: 東北大学

    2024/04 - 2026/03

  3. データ同化断層すべりモニタリングに向けた測地データ解析の革新

    加納将行

    2021/07 - 2026/03

  4. 余効変動の把握と予測に向けた地殻変動データ解析と粘弾性データ同化システムの構築

    加納 将行, 大谷 真紀子, 奥脇 亮, 伊東 優治

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業 基盤研究(C)

    Category: 基盤研究(C)

    Institution: 東北大学

    2021/04/01 - 2025/03/31

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    本研究はプレート沈み込み帯で繰り返し発生する巨大地震後に生じる地殻変動現象である余効変動に注目し、余効変動によって巨大地震が周囲に及ぼした応力擾乱がどのように緩和されていくのか、また次の巨大地震に向けてプレート境界においてどのように歪が蓄積されていくのかの解明に向けた数理基盤の構築を行う。余効変動を捉えた観測データには複数の要因による変動が含まれていることから、変動をその背景の要因に従って分離すると共に、プレート境界の断層すべりをより高精度に把握し、さらに定量的なすべりの将来予測を可能とする粘弾性データ同化システムを構築することを目指す。 2021年度は、余効変動を引き起こす地震時すべりの挙動および地震時すべりシグナルを把握するべく、2021年East Cape地震、2021年Haiti地震、2009年Gulf of California地震など、様々なテクトニック環境において発生した大地震の地震時震源過程解析を行った (Okuwaki et al. 2021、Okuwaki and Fan 2022、Fan, Okuwaki et al. 2022など)。また、高サンプリングのGNSSデータを購入し、2003年十勝沖地震の地震後および2015年Gorkha地震の地震時から地震後に得られた高サンプリングGNSSデータの解析を行い、30秒サンプリングで地殻変動時系列を推定した。加えて、30秒サンプリングのGNSS時系列のノイズ低減方法の性能評価と改良に取り組んだ（Itoh and Aoki 2022）。また、高サンプリングGNSSデータの同化に向けてKano et al. (2020)で開発したアジョイント法のプログラムを改良し、数値実験により開発手法を検証した。さらに、粘弾性データ同化システム構築の準備として、試験的に粘弾性変動時間発展の二次元数値モデルを作成した。

  5. Construction of next-generation data assimilation for the solid Earth science

    Nagao Hiromichi, KOYAGUCHI Takehiro, ICHIMURA Tsuyoshi, IWATA Takaki, MIZUSAKO Sadanobu, SUZUKI Akihiro, ISHIKAWA Daichi, KUROKAWA Takashi, KANO Masayuki, ITO Shin-ichi

    Offer Organization: Japan Society for the Promotion of Science

    System: Grants-in-Aid for Scientific Research

    Category: Grant-in-Aid for Scientific Research (B)

    Institution: The University of Tokyo

    2014/04/01 - 2018/03/31

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    This project has made considerable advances in data assimilation (DA) methodologies for the solid Earth science. We succeeded in developing a new four-dimensional variational method, which is a DA method applicable to simulation models having large degrees of freedom. We also applied DA to the real data obtained by a dense seismic observation array, developing a model-/data-driven DA methodology through an integration of the replica exchange Monte Carlo method. The obtained results were presented in many domestic and international conferences, and publised as papers in international journals. We are going to publish a book related to this issue. We convened special sessions in many conferences such as Japan Geoscience Union Meeting.

  6. スロースリップ発生場の摩擦特性の解明および発生予測のためのデータ同化手法の開発

    加納 将行

    Offer Organization: 日本学術振興会

    System: 科学研究費助成事業

    Category: 特別研究員奨励費

    Institution: 京都大学

    2011 - 2013

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    本研究では、数値シミュレーションと観測データを融合するデータ同化手法を用いて、スロースリップの発生機構の解明および予測可能性の検討を行うことを最終目的とする。平成25年度は、昨年度に引き続いて最終目的に向けた以下の基礎研究を行った。 1、GPS擬似データによるプレート境界面の摩擦パラメータの推定可能性の検討 地震発生シミュレーションのモデルと、余効すべり現象を再現した地表変位擬似観測データに対して、アジョイント法を適用し、余効すべり域の摩擦パラメータの推定およびすべりの時空間発展の予測に関する数値実験を行った。その結果、摩擦パラメータの推定値が、真値に比べて10%以内の誤差で得られることが分かった。これは、昨年度に行ったすべり速度を用いた数値実験と同様の結果であり、地表観測を用いても摩擦パラメータが推定できる可能性を示唆している。 2、2003年十勝沖地震への適用 1で開発した手法を摩擦パラメータに空間不均質性がある、より現実的なモデルにも適用可能な手法に改良し、2003年十勝沖地震時に得られた観測データに適用した。このとき、地表変位をインバージョンして得られたプレート境界面のすべり速度データを用いた場合と、地表変位を直接用いた場合の2種類のデータを用いた摩擦パラメータの推定を行った。どちらの結果でも、すべりの加速フェーズと減速フェーズが推定される領域において、小さな信頼区間で摩擦パラメータを拘束することができた。また、十勝沖地震時すべり域の東部と西部で摩擦パラメータが大きく異なることが分かった。

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