研究者詳細 - 伊藤　武男

論文 - 伊藤　武男

分割表示 >> ／全件表示 79 件中 1 - 79 件目

Probing asthenospheric density, temperature and elastic moduli below the Western United States 査読有り

T. Ito and M. Simons

Science 322 巻 ( 6032 ) 頁： 947-951 2011年4月

Physics-informed deep learning approach for modeling crustal deformation

Okazaki, T; Ito, T; Hirahara, K; Ueda, N

NATURE COMMUNICATIONS 13 巻 ( 1 ) 2022年11月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Nature Communications

The movement and deformation of the Earth’s crust and upper mantle provide critical insights into the evolution of earthquake processes and future earthquake potentials. Crustal deformation can be modeled by dislocation models that represent earthquake faults in the crust as defects in a continuum medium. In this study, we propose a physics-informed deep learning approach to model crustal deformation due to earthquakes. Neural networks can represent continuous displacement fields in arbitrary geometrical structures and mechanical properties of rocks by incorporating governing equations and boundary conditions into a loss function. The polar coordinate system is introduced to accurately model the displacement discontinuity on a fault as a boundary condition. We illustrate the validity and usefulness of this approach through example problems with strike-slip faults. This approach has a potential advantage over conventional approaches in that it could be straightforwardly extended to high dimensional, anelastic, nonlinear, and inverse problems.

DOI： 10.1038/s41467-022-34922-1

Web of Science

Scopus

PubMed

Asthenosphere rheology inferred from observations of the 2012 Indian Ocean earthquake 査読有り

Yan Hu, Roland Bürgmann, Paramesh Banerjee, Lujia Feng, Emma M. Hill, Takeo Ito, Takao Tabei, and Kelin Wang

Nature 2016年10月

Complex rupture during the 12 January 2010 Haiti Earthquake 査読有り

R. Briggs, A. Sladen, E. Fielding, C. Prentice, K. Hudnut, P. Mann, F. Taylor, A. Crone, R. Gold, T. Ito and M. Simons

Nature Geoscience 2010年5月

Subsiding Cities: A Case Study of Governance and Environmental Drivers in Semarang, Indonesia 査読有り国際共著 Open Access

Syarifah Aini Dalimunthe, Budi Heru Santosa, Gusti Ayu Ketut Surtiari, Abdul Fikri Angga Reksa, Ruki Ardiyanto,Sepanie Putiamini, Agustan, Takeo Ito and Rachmadhi Purwana

Urban Science 9(7) 巻 ( 266 ) 2025年7月

Physics-Informed Deep Learning for Forward and Inverse Modeling of Inplane Crustal Deformation 査読有り

Okazaki, T., Hirahara, K., Ito, T., Kano,M., & Ueda, N.

Journal of Geophysical Research:Machine Learning and Computation 2 巻 ( e2024JH000474 ) 2025年3月

Exploring Volcanic Activity Through Open Data in Mount Ruang’s 2024 Eruption 査読有り国際共著

Agustan, Takeo ITO, Estu Kriswati, Marina C.G. Frederik, Arif Aditiya, Djoko Nugroho

2024 IEEE Asia-Pacific Conference on Geoscience, Electronics and Remote Sensing Technology (AGERS) 2024年12月

Temporary slip speed increases during short-term slow slip events with durations of one to three hours Open Access

Katsumata A., Miyaoka K., Tsuyuki T., Itaba S., Tanaka M., Ito T., Takamori A., Araya A.

Earth, Planets and Space 76 巻 ( 1 ) 2024年12月

出版者・発行元：Earth, Planets and Space

Temporary slip speed increases with durations of 1–3 h were identified during short-term slow slip events in records of borehole and laser strainmeters in the Tokai region, Japan. They were found by searching for peaks of correlation coefficients between stacked strain data and ramp functions with rise times of 1 and 2 h. Although many of the strain steps were considered due to noise, some strain steps occurred with simultaneous activation of the deep tectonic tremors and shared source areas with the tremors. From 2016 to 2022, we observed five strain steps with simultaneous activation of tectonic tremors and coincidence of source locations with the tremors. Those strain steps occurred during short-term slow slip events and were temporary slip speed increases of the slow slip events. Those strain steps seemed to be related to successive occurrences with source migration of short-term slow slip events. The detrended strain steps corresponded to plate boundary slip events of moment magnitude around 5, which was consistent with the scaling law of slow earthquakes. Graphical Abstract: (Figure presented.)

DOI： 10.1186/s40623-024-01983-z

Open Access

Scopus

Temporary slip speed increases during short-term slow slip events with durations of one to three hours 査読有り

Earth, Planets and Space 76 巻 ( 45 ) 2024年3月

Evaluation of earthquake potential using a kinematic crustal block motion model in Java, Indonesia, based on GNSS observation 査読有り国際共著

R. Raharja, T. Ito, I. Meilano

Journal of Asian Earth Sciences: X 1 巻 2024年1月

御嶽⼭周辺におけるブーゲー異常

⽩⼭智之, 市原寛, 伊藤武男, ⼯藤健, 堀川信⼀郎, 松廣健⼆郎, 茂⽊透, 本多亮, 宮城洋介

日本火山学会講演予稿集 2024 巻 ( 0 ) 頁： 148 - 148 2024年

Present-day land subsidence over Semarang revealed by time series InSAR new small baseline subset technique

Aditiya A., Ito T.

International Journal of Applied Earth Observation and Geoinformation 125 巻 2023年12月

出版者・発行元：International Journal of Applied Earth Observation and Geoinformation

Over the last two decades, Semarang, located in the central region of Java island, Indonesia, has been undergoing significant land subsidence. Mainly attributed to reservoir compaction and fluid extraction, this subsidence has pronounced effects in coastal regions. However, the existing study on the details of subsidence and its application to accurately depict present circumstances has been insufficient. Utilizing the new small baseline subset technique and C-band SAR data from 2015 to 2022, this study delineates the spatial boundaries of land subsidence in Semarang and surrounding areas. Atmospheric effects were mitigated using the GACOS model during InSAR processing. The study reveals dominant vertical movements in Semarang's north coastal area, characterized by rapid and extensive changes. In contrast, horizontal movement shows relatively small changes in number to the east of the study area. Time series analysis indicates maximum subsidence rate of 100–120 mm/year in the northern and eastern part of Semarang and Demak. Available data from GNSS stations ensures the reliability of these findings. The correlation coefficient of 0.86 indicated substantial association between groundwater and deformation. Approximately 20 % of Semarang's land area is affected by land subsidence, which is notably more prevalent in alluvial soils and densely populated regions. In Demak, subsidence is primarily observed in agricultural regions, whereas in Kendal, the 50 mm/year subsidence rate represents a growing concern. This accelerating phenomenon poses substantial risks to the local environment and economic sectors. All authorities must harmonize regulations to force their roles, produce details spatial plan maps, and establish mitigation and adaptation infrastructure to handle the current crisis realistically.

DOI： 10.1016/j.jag.2023.103579

Scopus

Time Series InSAR Analysis over Jakarta Metropolitan Area 招待有り査読有り国際共著

Agustan, Takeo Ito, Estu Kriswati, Hari Priyadi, Heri Sadmono, Rika Hernawati

2022 IEEE Asia-Pacific Conference on Geoscience, Electronics and Remote Sensing Technology 2023年4月

Time Series InSAR for Ground Deformation Observation in Semarang Area, Central Java 査読有り

APSAR 2023 - 2023 8th Asia-Pacific Conference on Synthetic Aperture Radar 2023年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：APSAR 2023 - 2023 8th Asia-Pacific Conference on Synthetic Aperture Radar

The initiatives of open data and open platforms, combined with on-demand data processing in Synthetic Aperture Radar (SAR), enable more straightforward and accessible ground deformation research worldwide. The Alaska Satellite Facility Distributed Active Archive Center (ASF DAAC) provides high-quality interferogram combination pairs based on the Small Baseline Subset (SBAS) technique and on-demand InSAR data analysis known as HyP3. HyP3 offers unwrapped phase data from Sentinel-1 satellites and other derived products that can be utilized with open-source deformation software such as Mintpy. This research aims to assess the quality of interferogram combination pairs by configuring networks of perpendicular and temporal baselines for observing ground deformation in Semarang, Central Java, Indonesia. The study demonstrates that HyP3 products enable time series analysis to determine deformation rates. Over 8.4 years, from November 15th, 2014, to April 14th, 2023, the Simpang Lima landmark in Semarang experienced an approximate subsidence rate of -0.87 cm/year. However, the maximum subsidence rate of approximately 11 cm/year was observed in the southeastern part of Semarang.

DOI： 10.1109/APSAR58496.2023.10388980

Scopus

Machine-learning-based detection of volcano seismicity using the spatial pattern of amplitudes 査読有り

Maeda, Y; Yamanaka, Y; Ito, T; Horikawa, S

GEOPHYSICAL JOURNAL INTERNATIONAL 225 巻 ( 1 ) 頁： 416 - 444 2021年4月

記述言語：日本語掲載種別：研究論文（学術雑誌）出版者・発行元：Geophysical Journal International

We propose a new algorithm, focusing on spatial amplitude patterns, to automatically detect volcano seismic events from continuous waveforms. Candidate seismic events are detected based on signal-to-noise ratios. The algorithm then utilizes supervised machine learning to classify the existing candidate events into true and false categories. The input learning data are the ratios of the number of time samples with amplitudes greater than the background noise level at 1 s intervals (large amplitude ratios) given at every station site, and a manual classification table in which 'true' or 'false' flags are assigned to candidate events. A two-step approach is implemented in our procedure. First, using the large amplitude ratios at all stations, a neural network model representing a continuous spatial distribution of large amplitude probabilities is investigated at 1 s intervals. Second, several features are extracted from these spatial distributions, and a relation between the features and classification to true and false events is learned by a support vector machine. This two-step approach is essential to account for temporal loss of data, or station installation, movement, or removal. We evaluated the algorithm using data from Mt. Ontake, Japan, during the first ten days of a dense observation trial in the summit region (2017 November 1-10). Results showed a classification accuracy of more than 97 per cent.

DOI： 10.1093/gji/ggaa593

Web of Science

Scopus

Land Subsidence Rate of Jakarta Metropolitan Area Observed By Stacking Sentinel-1 Data

Agustan, A; Kriswati, E; Ito, T; Abdullah, FM; Anantasena, Y; Nugroho, D

2021 IEEE ASIA-PACIFIC CONFERENCE ON GEOSCIENCE, ELECTRONICS AND REMOTE SENSING TECHNOLOGY (AGERS-2021) 頁： 69 - 72 2021年

出版者・発行元：2021 IEEE Asia-Pacific Conference on Geoscience, Electronics and Remote Sensing Technology, AGERS 2021 - Proceeding

The growth of Jakarta metropolitan area as capital city is increase from time to time. Even the rate of population growth tends to decline, but population still stresses Jakarta environment. The surface changes and ground deformation related to city growth can be observed continuously by satellite-based remote sensing. The launch of Sentinel-1 satellite with radar mission through Copernicus, which is a joint initiative of the European Commission and European Space Agency, enables continuous observation of earth's surface. This paper describes a study of ground deformation rate of Jakarta metropolitan area observed by processing Sentinel-1 data based on interferometric Synthetic Aperture Radar method. Only small perpendicular baselines of SAR data pairs are selected from 2015 to 2019 to avoid the use of external Digital Elevation Model data. The land subsidence rate is obtained by stacking the unwrapped phase and it is found that the rate is different across the region. In the western part, the rate is around -2cm/year whereas in the eastern part is around -3cm/year. The pattern and the rate of land subsidence are confirmed by ascending and descending orbit direction.

DOI： 10.1109/AGERS53903.2021.9617239

Web of Science

Scopus

2016年熊本地震合同地震観測データ

志藤あずさ, 光岡郁穂, 松本聡, 松島健, 相澤広記, 清水洋, 内田和也, 神薗めぐみ, 手操佳子, 中元真美, 宮町凛太郎, 一柳昌義, 大園真子, 岡田和見, 勝俣啓, 高田真秀, 高橋浩晃, 谷岡勇市郎, 山口照寛, 小菅正裕, 東龍介, 内田直希, 江本賢太郎, 太田雄策, 岡田知己, 海田俊輝, 小園誠史, 鈴木秀市, 高木涼太, 出町知嗣, 中原恒, 中山貴史, 平原聡, 松澤暢, 三浦哲, 山本希, 今西和俊, 内出崇彦, 吉見雅行, 青井真, 浅野陽一, 上野友岳, 藤田英輔, 阿部英二, 飯高隆, 岩崎貴哉, 加藤愛太郎, 蔵下英司, 酒井慎一, 椎名高裕, 芹澤正人, 田中伸一, 中川茂樹, 平田直, 増田正孝, 宮川幸治, 八木健夫, 渡邉篤志, 後藤和彦, 伊藤武男, 奥田隆, 寺川寿子, 堀川信一郎, 前田裕太, 松廣健二郎, 山中佳子, 渡辺俊樹, 飯尾能久, 片尾浩, 加納靖之, 津田寛大, 三浦勉, 村本智也, 山下裕亮, 大久保慎人, 山品匡史, 大倉敬宏, 中尾茂, 平野舟一郎, 宮町宏樹, 八木原寛

地震　第２輯 73 巻 ( 0 ) 頁： 149 - 157 2020年10月

Earthquake potential in Costa Rica using three scenarios for the central Costa Rica deformed belt as western boundary of the Panama microplate 査読有り

Carvajal-Soto, LA; Ito, T; Protti, M; Kimura, H

JOURNAL OF SOUTH AMERICAN EARTH SCIENCES 97 巻頁： 102375 2020年1月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of South American Earth Sciences

The Central Costa Rica Deformed Belt (CCRDB) is a diffuse faulting area that represents the western border of the Panama Microplate. Using the Markov Chain – Monte Carlo method and under three scenarios of the spatial distribution of the CCRDB, we analyzed the inter-seismic crustal deformation in Costa Rica and its surroundings based on the results of the Global Navigation Satellite System (GNSS) observations for Costa Rica, Nicaragua, and Panama. We assumed that the observed inter-seismic crustal deformation on the surface is a result of the kinematic effects of the rigid tectonic blocks motion, the elastic deformation due to the block interface interactions and the internal strain inside of the tectonic blocks. Assuming that the seismic moment in the subduction and inland interfaces is accumulated only as an elastic strain and is then released co-seismically, the resulting seismic moment accumulated rates reflect the capacity for producing earthquakes Mw > 8 along the Cocos Plate convergence and earthquakes Mw > 7 along the inland interfaces. Although these are the values that the modeling outputs, limited historical data suggests that this earthquake potential might be overestimated, but the historical seismicity in Costa Rica is still short for disesteeming higher earthquake potential levels.

DOI： 10.1016/j.jsames.2019.102375

Web of Science

Scopus

Ground Deformation Identification related to 2018 Lombok Earthquake Series based on Sentinel-1 Data 査読有り

Agustan, Rahma, N. Hanifa, Yudi Anantasena, M. Sadly, Takeo Ito

The 4th International Conference of Indonesian Society for Remote Sensing 280 巻 ( 1 ) 2019年8月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：IOP Conference Series: Earth and Environmental Science

Lombok Island was hit by a series of earthquakes in July and August 2018 with magnitude 6 class. This series of earthquakes resulted in fatalities and material losses that even reached Sumbawa Island to the east of Lombok Island. The earthquake was triggered by Flores back arc thrust resulting in ground deformation. Ground deformation can be identified by satellite-based remote sensing method. The Sentinel-1A and Sentinel-1B satellites are two satellites carrying C-band SAR sensors with a temporal resolution of 12 days each for the same orbit, and the difference in time between the two is 6 days. Therefore, ground deformation related to seismo-tectonic or volcanic activities can be identified by interfering two SAR images (interferometric synthetic aperture radar or InSAR) at least in 6 days. By utilizing Sentinel Application Platform (SNAP) a free open source software (FOSS) and combining with other InSAR software, an interferogram that represents line of sight displacement (LOS) between ground and satellite can be generated. Line of sight displacement can then be interpreted as ground deformation signals. It is shown that the series of Lombok earthquake cause an uplift up to 70cm and subsidence up to 25cm. This deformation affects areas around epicentre. A field survey was conducted to obtain information directly and it was seen that the ground deformation that was identified with the InSAR technique were consistent with the findings in the field. This shows the advantages of remote sensing in terms of ability to cover a wide area in a short time.

DOI： 10.1088/1755-1315/280/1/012004

Scopus

Interplate Coupling Distribution Along the Nankai Trough in Southwest Japan Estimated From the Block Motion Model Based on Onshore GNSS and Seafloor GNSS/A Observations 査読有り

Kimura Hiroshi, Tadokoro Keiichi, Ito Takeo

JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH 124 巻 ( 6 ) 頁： 6140 - 6164 2019年6月

Evaluation of the 2012 Indian Ocean coseismic fault model in 3-D heterogeneous structure based on vertical and horizontal GNSS observation, 査読有り

C. Pratama, T. Ito, T. Tabei, F. Kimata, E. Gunawan, Y. Ohta, T. Yamashina, I. Nurding, D. Sugiyanto, U. Muksin, N. Ismail, I. Meilano

AIP Conference Proceedings 1987 巻 ( 1987 ) 頁： 020011 2018年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AIP Conference Proceedings

Lack of observation network in the vicinity of oceanic intraplate earthquake lead the estimation of coseismic fault slip with high uncertainty. Satriano et al. [2] and Wei et al. [3] found NNE trending left-lateral slip as the primary features. In another hand, Yue et al. [4] and Hill et al. [5] proposed WNW trending right-lateral faults structure as the main characteristic. Here, we investigate the coseismic fault model that could explain the coseismic offset both vertical and horizontal in a 3-D heterogeneous earth structure. We constructed finite element model that include three-dimensional velocity structure, topography/bathymetry, spherical-earth and subducting slab. In this study, we employed scaling slip to adjust slip amount and total seismic moment. Instead of original slip amount, we preserve seismic moment as a basis comparison. Based on vertical and horizontal observation data, WNW trending right-lateral fault could fit better than NNE trending left-lateral fault. The present study demonstrates best-fit calculation using scaling slip optimized to the horizontal or vertical observation lead the both fault model worsen the misfit of vertical or horizontal component, respectively. This result analysis indicates a trade-off between vertical and horizontal component and reflects the importance of revisiting the fault slip modeling incorporating vertical and horizontal data equally.

DOI： 10.1063/1.5047296

Web of Science

Scopus

Spatio-temporal afterslip distribution following the 2011 Tohoku-Oki earthquake using 3D viscoelastic green's functions 査読有り

Ito T., Suzuki S., Sato K., Hyodo M.

AIP Conference Proceedings 1987 巻 ( 1987 ) 頁： 020056 2018年7月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：AIP Conference Proceedings

On March 11, 2011, the Tohoku-Oki earthquake (Mw 9.0) occurred on the plate interface of the subducting Pacific plate. During the co- and post-seismic periods, almost all GEONET and seafloor observations detected eastward crustal deformation. However, seafloor observations around main raptured zone moved in a westward direction during the post-seismic period. In this study, we estimate the spatio-temporal slip distribution during the co- and post-seismic periods from observed crustal deformations, such as GEONET and seafloor observations. For inversion, we use a viscoelastic Green's function derived from a three-dimensional finite element method considering the underground structure. The estimated maximum co-seismic slip is approximately 60m from the Japan Trench. Off Iwate prefecture, the moment magnitude and maximum afterslip 2.5 years after the Tohoku-Oki earthquake are approximately 8.13 and 2.0m, respectively. The afterslip distributions differ from the co-seismic slip distribution, and the relationship between the co-seismic and afterslip regions is complementary.

DOI： 10.1063/1.5047341

Web of Science

Scopus

Preface: International Symposium on Earth Hazard and Disaster Mitigation 2017

Meilano I., Cummins P., Zulfakriza , Ito T.

AIP Conference Proceedings 1987 巻 2018年7月

Coseismic Slip Distribution of the 2 July 2013 Mw 6.1 Aceh, Indonesia, Earthquake and Its Tectonic Implications 査読有り

Endra Gunawan, Sri Widiyantoro, Shindy Rosalia, Mudrik Rahmawan, Daryono, Irwan Meilano, Pepen Supendi, Takeo Ito, Takao Tabei, Fumiaki Kimata, Yusaku Ohta, Nazli Ismail

Bulletin of the Seismological Society of America 108 巻 ( 4 ) 頁： 1918 - 1928 2018年6月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Bulletin of the Seismological Society of America

This study investigates the coseismic slip distribution of the 2 July 2013 Mw 6.1 Aceh earthquake using Global Positioning System (GPS) data, measured geological surface offsets, and an aftershock distribution for a period of four days after the mainshock. We use the aftershock distribution to constrain the fault-plane strike of a right-lateral fault identified as the Pantan Terong segment. We estimate the coseismic slip distribution with dip angle information from the Global Centroid Moment Tensor (CMT) (model 1) and U.S. Geological Survey (USGS) (model 2) catalogs. We also estimate the coseismic slip distribution using another two fault models. Model 3 is constructed on a left-lateral fault, the Celala segment, which is perpendicular to the Aceh segment of the Sumatran fault, and model 4 is constructed using the multiple faults in models 2 and 3. We further estimate the coseismic slip distribution of this earthquake by employing an elastic dislocation model, inverting only the GPS displacements for model 3 and jointly inverting GPS displacements and geological surface offsets for models 1, 2, and 4. Minimum misfit between data and model is obtained with model 3, suggesting that the earthquake slip occurred along a left-lateral fault. Analysis of stress transfer caused by the 2013 earthquake indicates that the stress level along the Pantan Terong segment is > 0:4 bar and the southeast part of Aceh segment was brought ∼0:3 bar closer to failure, suggesting a possible earthquake occurrence in the future. This work demonstrates that the seismicity-derived fault plane fails to predict the surface displacement, and that the inferred Celala segment produces positive stress on Pantan Terong segment and potentially triggered all the aftershocks.

DOI： 10.1785/0120180035

Web of Science

Scopus

Transient rheology of the oceanic asthenosphere following the 2012 Indian Ocean Earthquake inferred from geodetic data 査読有り

Pratama C., Ito T., Sasajima R., Tabei T., Kimata F., Gunawan E., Ohta Y., Yamashina T., Ismail N., Nurdin I., Sugiyanto D., Muksin U., Meilano I.

Journal of Asian Earth Sciences 147 巻頁： 50 - 59 2017年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Journal of Asian Earth Sciences

Postseismic motion in the middle-field (100–500 km from the epicenter) geodetic data resulting from the 2012 Indian Ocean earthquake exhibited rapid change during the two months following the rupture. This pattern probably indicates multiple postseismic deformation mechanisms and might have been controlled by transient rheology. Therefore, the relative contribution of transient rheology in the oceanic asthenosphere and afterslip in the oceanic lithosphere should be incorporated to explain short- and long-term transitional features of postseismic signals. In this study, using two years of post-earthquake geodetic data from northern Sumatra, a three-dimensional spherical-earth finite-element model was constructed based on a heterogeneous structure and incorporating transient rheology. A rheology model combined with stress-driven afterslip was estimated. Our best-fit model suggests an oceanic lithosphere thickness of 75 km with oceanic asthenosphere viscosity values of 1 × 1017 Pa s and 2 × 1018 Pa s for the Kelvin and Maxwell viscosity models, respectively. The model results indicate that horizontal landward motion and vertical uplift in northern Sumatra require viscoelastic relaxation of the oceanic asthenosphere coupled with afterslip in the lithosphere. The present study demonstrates that transient rheology is essential for reproducing the rapidly changing motion of postseismic deformation in the middle-field area.

DOI： 10.1016/j.jseaes.2017.07.049

Web of Science

Scopus

Anisotropic Horizontal Thermal Contraction of Young Oceanic Lithosphere Inferred From Stress Release Due To Oceanic Intraplate Earthquakes 査読有り

Sasajima R., Ito T.

Tectonics 36 巻 ( 10 ) 頁： 1988 - 2021 2017年10月

記述言語：英語掲載種別：研究論文（学術雑誌）出版者・発行元：Tectonics

How freely the oceanic lithosphere contracts horizontally due to thermal contraction is important information, because it reflects the boundary condition of the oceanic lithosphere, which includes information regarding the magnitude of driving/resisting forces of plate tectonics. We investigated the horizontal thermal contraction of young oceanic lithosphere using an analysis of the intraplate stress release due to oceanic intraplate earthquakes (OCEQs) and numerical simulations. The stress release due to OCEQs in young oceanic lithosphere (5–15 Ma) shows significant differences between the spreading directional component and the ridge-parallel component. The extensional stress release of the ridge-parallel component is 6 times as large as that of the spreading directional component, while the compressional stress release of the ridge-parallel component is one seventh that of the spreading directional component. We conducted a numerical simulation of the thermal stress evolution of the oceanic lithosphere to investigate how the difference in the horizontal contraction rates between the spreading direction and the ridge-parallel direction can explain the observed anisotropic stress release. The result indicates that young oceanic lithosphere (5–15 Ma) barely contracts in the ridge-parallel direction (only 0–30% of the spreading directional contraction rate), while it contracts freely in the spreading direction due to the weakness of the oceanic ridge strength and the low-viscosity asthenosphere. From the results, we constrained the magnitude of the basal traction working on the bottom of the oceanic lithosphere to be smaller than 0.44 MPa.

DOI： 10.1002/2017TC004680

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Scopus

B-value and slip rate sensitivity analysis for PGA value in Lembang fault and cimandiri fault area 査読有り

Pratama C., Ito T., Meilano I., Nugraha A.

AIP Conference Proceedings 1857 巻 2017年7月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：AIP Conference Proceedings

We examine slip rate and b-value contribution of Peak Ground Acceleration (PGA), in probabilistic seismic hazard maps (10% probability of exceedence in 50 years or 500 years return period). Hazard curve of PGA have been investigated for Sukabumi and Bandung using a PSHA (Probabilistic Seismic Hazard Analysis). We observe that the most influence in the hazard estimate is crustal fault. Monte Carlo approach has been developed to assess the sensitivity. Uncertainty and coefficient of variation from slip rate and b-value in Lembang and Cimandiri Fault area have been calculated. We observe that seismic hazard estimates are sensitive to fault slip rate and b-value with uncertainty result are 0.25 g dan 0.1-0.2 g, respectively. For specific site, we found seismic hazard estimate are 0.49 + 0.13 g with COV 27% and 0.39 + 0.05 g with COV 13% for Sukabumi and Bandung, respectively.

DOI： 10.1063/1.4987083

Web of Science

Scopus

Geodetic and geomorphic evaluations of earthquake generation potential of the northern Sumatran fault, Indonesia 査読有り

Tabei T., Kimata F., Ito T., Gunawan E., Tsutsumi H., Ohta Y., Yamashina T., Soeda Y., Ismail N., Nurdin I., Sugiyanto D., Meilano I.

International Association of Geodesy Symposia 145 巻頁： 21 - 28 2017年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：International Association of Geodesy Symposia

We have conducted geodetic and geomorphic observations in the northernmost part of Sumatra, Indonesia to monitor strain accumulation in the vicinity of the northern Sumatran fault. Evaluation of the earthquake generation potential in this region is highly urgent because of a large fault slip rate, absence of major earthquakes for more than 100 years and recent Coulomb stress increase on the fault due to the 2004 Sumatra-Andaman earthquake (Mw 9:2).We have deployed Aceh GPS Network for the Sumatran Fault System (AGNeSS) since 2005. The data collected have been used for estimating slip/locking distribution of the Sumatran fault and constructing a comprehensive model for postseismic deformation after the 2004 event. Tectonic geomorphic features are also important to reveal long-term slip history of the fault. We have used high-resolution stereo-paired ALOS (Advanced Land Observing Satellite) PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) satellite images to map the surface trace of the Sumatran fault and conducted field observations to ensure the trace by geomorphic and geologic evidence. We introduce preliminary results of the fault mapping together with a brief description of the crustal deformation field detected by GPS.

DOI： 10.1007/1345_2015_200

Scopus

Inhomogeneous spherical-earth finite element model of coseismic offset due to the 2012 Indian Ocean Earthquake 査読有り

Pratama C., Ito T., Tabei T.

AIP Conference Proceedings 1857 巻 2017年

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）出版者・発行元：AIP Conference Proceedings

On April 11, 2012, a Mw 8.6 earthquake struck off the west coast of northern Sumatra approximately 300 km west of the Sunda trench following by Mw 8.2 two hours afterward. The 2012 Indian Ocean Earthquake sequence, which was the largest intraplate earthquake in recorded history, yielded seismic moment of 1.2-1.3 × 1022 N m and 0.2-0.3 × 1022 N m for the main shock (Mw 8.6) and the after shock (Mw 8.2), respectively. Aceh GPS Network for Sumatran Fault System (AGNeSS) observed a predominantly ENE coseismic offset up to 10 cm while the sites on the Andaman Island observed southward and southern part Sumatra GPS Array (SuGar) network observed northward. Limited far-field and inland GPS observation network might lead the homogeneous and half-space model insufficient to explain the coseismic offset. In that of sense, in order to estimate more realistic surface displacement due to complex subduction and far-field GPS station, we consider developing inhomogeneous three-dimensional finite element model incorporate subducting slab, three-dimensional velocity earth structure, realistic topography and bathymetry as well as sphericity of the earth. We calculate coseismic offset by forward modeling using slip distribution as reported from Wei et al. [7]. This study investigates the effect of inhomogeneous structure and spherical geometry model in reproducing actual coseimic offset due to 2012 Indian Ocean Earthquake.

DOI： 10.1063/1.4987066

Web of Science

Scopus

Measuring Deformation in Jakarta through Long Term Synthetic Aperture Radar (SAR) Data Analysis 査読有り

Agustan, Albertus Sulaiman, Takeo Ito

2nd International Conference of Indonesian Society for Remote Sensing (ICOIRS) 47 巻 ( 1 ) 2016年12月

Strain rate dependency of oceanic intraplate earthquake b-values at extremely low strain rates 査読有り

R.Sasajima and T. Ito

J. Geophys. Res 2016年6月

Co-seismic offsets due to two earthquakes (Mw 6.1) along the Sumatran fault system derived from GNSS measurements 査読有り

T. Ito, E. Gunawan, F. Kimata, T. Tabei, I. Meilano, Agustan, Y. Ohta, N. Ismail, I. Nurdin and D. Sugiyanto

Earth, Planets and Space 2016年4月

The Sensitivity of Surface Mass Loading Displacement Response to Peturbations in the Elastic Structure of the Crust and Mantle 査読有り

H. R. Martens, L. Rivera, M. Simons, and T. Ito

J. Geophys. Res. Solid Earth 121 巻 2016年3月

地震や火山の活動を捉えるミリメートル制度のGNSS観測

伊藤武男

名古屋大学理学部技術報告 ( 20 ) 頁： 19-23 2016年3月

測地学的手法を統合的に活用した地球内部構造とダイナミクスの解明招待有り査読有り

伊藤武男

測地学会誌 61 巻 ( 1 ) 頁： 1-15 2015年4月

海洋潮汐がトリガーとなる氷河地震

伊藤武男，古本宗充

月刊地球 425 巻 ( 37 ) 頁： 37-43 2015年2月

A comprehensive model of postseismic deformation of the 2004 Sumatra-Andaman earthquake deduced from GPS observations in northern Sumatra 査読有り

E. Gunawan, T. Sagiya, T. Ito, F. Kimata, T. Tabei, Y. Ohta, I. Meilano, H. Z. Abidine, Agustan, I. Nurdin and D. Sugiyanto

Journal Asian Earth Sciences 頁： Journal Asian Earth Sciences 2014年

Isolating along-strike variations in the depth extent of shallow creep and fault locking on the northern Great Sumatran Fault 査読有り

Ito, T., E. Gunawan, F. Kimata, T. Tabei, M. Simons, I. Meilano, Agustan, Y. Ohta, I. Nurdin, and D. Sugiyanto

Journal of Geophysical Research 2012年5月

Slip distribution of the 2011 off the Pacific coast of Tohoku Earthquake inferred from geodetic data 査読有り

Takeo Ito, Kazuhiro Ozawa, Tsuyoshi Watanabe, and Takeshi Sagiya

Earth Planets Space 63 巻頁： 627-630 2011年9月

Ground deformation detected by AGNeSS (Aceh GPS Network for Sumatran fault System) in North Sumatra after the 2004 Sumatra-Andaman earthquake

Endra Gunawan, Takeo Ito, Fumiaki Kimata, Takeshi Sagiya, Takao Tabei, Didik Sugiyanto/Irwandi, Irwan Meilano, Mipi A. Kusuma, Hasanuddin Z. Abidin, Agustan

The 6th Investigation Report of 2004 Northern Sumatra Earthquakes 頁： 112-121 2010年7月

Spatio-temporal distribution of magma intrusions inducing repeated earthquake swarms off the east coast of the Izu peninsula, central Japan, for 1973-1998 査読有り

Masayuki Murase, Takeo Ito, Yoshinari Hayashi, Takeshi Sagiya, Fumiaki Kimata and Hidefumi Watanabe

Journal of Volcanology and Geothermal Research 193 巻 ( 1-2 ) 頁： 25-36 2010年3月

スマトラ島北西部のスマトラ断層における地震発生ポテンシャル

伊藤武男, Endra Gunawan, 木股文昭, 田部井隆雄, Irwandi, Agstan, Irwan Meilano, Mark Simons

名古屋大学環境学研究科 2004 年北部スマトラ地震調査報告VI 頁： 107-111 2010年

High resolution mapping of Earth tide response based on GPS data in Japan 査読有り

Takeo Ito, M. Okubo, T. Sagiya

Journal of Geodynamics 頁： 10.1016/j.jog.2009.09.012 2009年11月

Crustal Deformation Studies in Java (Indonesia) Using GPS 査読有り

H. Z. Abidin, H. Andreas, T. Kato, T. Ito, I. Meilano, F. Kimata, D. H. Natawidjaya, H. Harjono

Journal of Earthquake and Tsunami 3 巻 ( 2 ) 頁： 76-88 2009年10月

Field challenge of continues GPS array maintenance on Sumatra Fault: report of the August 2008 AGNeSS continue site investigation

Irwandi, T. Ito, ,F. Kimata

The 5th Investigation Report of 2004 Northern Sumatra Earthquakes, Graduate School of Environmental Studies, Nagoya University 頁： 109-118 2009年5月

スマトラGPS観測網（AGNeSS）のシステムの紹介

伊藤武男、木股文昭、Agstan、Endra Gunawan、田部井隆雄、Irwan Meilano、Didik Sugiyanto、Irwandi

名古屋大学全学技術センター（理学）装置開発系技術報告 4 巻頁： 26-29 2009年

担当区分：筆頭著者記述言語：日本語掲載種別：研究論文（大学，研究機関等紀要）

インドネシアスマトラ島においてGPS観測網を展開した．本論文は，その際に用いた観測システムの紹介をしている．このGPS観測網は観測データをオフラインで取得しているが，電力供給などが不安定なため，ソーラーパネルを併用した観測となっている．一方，観測機器は予算の都合上，一昔前の観測機器を用いているため，現地収録のメモリが小さいため，数日しか観測できない．そのため，超小型PC　(20cm×12cm×3cm)を現地に設置して，自動でデータを収集するシステムを構築した．

Coseismic and postseismic deformation related to the 2007 Chuetsu-oki, Niigata Earthquake 査読有り

Ohta, Y., S. Miura, T. Iinuma, K. Tachibana, T. Matsushima, H. Takahashi, T. Sagiya, T. Ito, S. Miyazaki, R. Doke, A. Takeuchi, K. Miyao, A. Hirao, T. Maeda, T. Yamaguchi, M. Takada, M. Iwakuni, T. Ochi, I. Meilano, and A. Hasegawa

Earth Planets Space 60 巻 ( 11 ) 頁： 1081-1086 2008年11月

Postseismic slip associated with the 2007 Chuetsu-oki, Niigata, Japan, Earthquake (M 6.8 on 16 July 2007) as inferred from GPS data 査読有り

Takeshi Iinuma, Yusaku Ohta, Satoshi Miura, Kenji Tachibana, Takeshi Matsushima, Hiroaki Takahashi, Takeshi Sagiya, Takeo Ito, Shin'ichi Miyazaki, Ryosuke Doke, Akira Takeuchi, Kayo Miyao, Akihiko Hirao, Takahiro Maeda, Teruhiro Yamaguchi, Masamitsu Takada, Makiko Iwakuni, Tadafumi Ochi, Irwan Meilano, and Akira Hasegawa

Earth Planets Space 60 巻 ( 11 ) 頁： 1087-1091 2008年11月

Post-seismic crustal movements derived from GPS observations due to the 2004 Sumatra-Andaman earthquake

T.Kato, C.D.Reddy, S.K. Prajapati, F.Kimata, Agustan, I.Meilano, Y.Ohta, T.Ito, D.Darmawan, H.Andreas, H.Z.Abidin, M.A.Kusuma, D.Sugianto, T.Tabei, M.Satomura, P.Wu and M.Hashimoto

Proceedings of the Inernational Symposium on the Restoration Program from Giant Earthquaeks and Tsunamis 頁： 43-48 2008年1月

*The construction of new dense GPS observation network: AGNeSS (Aceh GPS Network for Sumatran Fault System)

T.Ito, Agustan, I.meilano, T.Tabei and F.Kimata

Proceedings of the Inernational Symposium on the Restoration Program from Giant Earthquaeks and Tsunamis 頁： 63-67 2008年1月

Post-seismic Phase Duration of the 2004 Sumatra-Andaman Earthquake as Estimated from GPS Continuous Data

H.Z.Abidin, I.Malra, H.Andreas, I.Meilano, F.Kimata, T.Ito, Y.Ohtra, Agustan and D.Sugiyanto

Proceedings of the Inernational Symposium on the Restoration Program from Giant Earthquaeks and Tsunamis 頁： 57-61 2008年1月

インドネシア国スマトラにおけるGPS観測のための予備調査ースマトラのGPS観測による2004年アチェ・アンダマン地震の滑り分布の推定ー

木股文昭・伊藤武男・太田雄策・Meilano IRWAN・田部井隆雄

防災科学技術研究所資料 304 巻 2007年3月

Two Yeares GPS Observation in Aceh

M. Irwan, Y. Ohta, F. Kimata, T. Ito, T. Tabei, D. Darmawan, H. Andreas, A. Hasannudin, K. Mipi, S. Sugiyanto, Agustan

The 3rd Investigation Report of 2004 Northern Sumatra Earthquakes, Graduate School of Environmental Studies, Nagoya University 頁： 7－10 2007年

スマトラアンダマン地震の地震測地学的な側面からの知見

伊藤武男, 太田雄策, Irwan Meilano, 木股文昭

頁： 11－14 2007年

Time-dependent model for volume changes in pressure sources at Asama volcano, central Japan due to vertical deformations detected by precise leveling during 1902-2005 査読有り

Masayuki Murase, Koji Ono, Takeo Ito, Rikio Miyajima, Hitoshi Mori, Hiroshi Aoyama, Hiromitu Oshima, Yuka Yoshida, Akihiko Terada, Eturo Koyama, Toyotarou Takeda, Hidefumi Watanabe, Fumiaki Kimata, Naoyuki Fujii

Journal of Volcanology and Geothermal Research 164 巻頁： 54-75 2007年

Preliminary report on crustal deformation surveys and tsunami measurements caused by the july 17, 2006 South off Java Island Earthquake and Tsunami, Indonesia 査読有り

Teruyuki Kato, Takeo Ito, Hasanuddin Z. Abidin, and Agustan

Earth Planets Space 59 巻頁： 1055-1059 2007年

High-resolution aftershock observations in the source region of the 2004 mid-Niigata Prefecture Earthquake 査読有り

Aitaro Kato and The Research Team of aftershock observations for the 2004 mid-Niigata Prefecture Earthquake

Earth Planets Space 59 巻頁： 923-928 2007年

地震火山・防災研究センターの観測網のIP網化について

伊藤武男

名古屋大学全学技術センター（理学）装置開発系技術報告 1 巻頁： 41-44 2006年

担当区分：筆頭著者記述言語：日本語掲載種別：研究論文（大学，研究機関等紀要）

当センターの観測システムをIP網化した際のノウハウを記した報告書です．とくに，現状のシステムを止める事無く，新しいシステムに移行することや，地震観測網と地殻変動連続観測網との統合などについて，記してある．これらの技術は一般的なネットワーク技術であるため，汎用性は高い．

Evaluation of visco-elastic and poro-elastic deformations following 2004 Sumatra-Andaman earthquake

T. Ito, S. Kawamoto, Y. Ohota, I. Meilano and F. Kimata

Investigation Report of 2004 Northern Sumatra Earthquakes (part 2), Graduate School of Environmental Studies, Nagoya University 頁： 114-119 2006年

Crustal deformation following the 2004 Sumatra-Andaman earthquake in the northern Sumatra region (Preliminary Report)

Y. Ohota, M. Irwan, T. Ito, F. Kimata, T. Tabei and D. Sugiyanto

Investigation Report of 2004 Northern Sumatra Earthquakes (part 2), Graduate School of Environmental Studies, Nagoya University 頁： 109-113 2006年

富士山における人工地震探査―観測および走時の読み取り― 査読有り

及川純・鍵山恒臣・田中聡・宮町宏樹・筒井智樹・池田靖・潟山弘明・松尾道・大島弘光・西村裕一・山本圭吾・渡辺俊樹・山崎文人・渡辺秀文・藤井敏嗣・中田節也・武尾実・大湊隆雄・金子隆之・吉本充宏・竹田豊太郎・小山悦郎・長田昇・坂守・羽田敏夫・橋本信一・辻浩・井本良子・増谷文雄・嶋野岳人・古川晃子・鷺谷威・藤井巌・林能成・宮島力男・山田守・奥田隆・伊藤武男・橋本武志・前川徳光・鈴木敦生・伊藤拓・三浦康・植木貞人・西村太志・仁田交市・佐藤峰司・下村陽一・野上健治・鬼澤真也・小山田浩子・舟崎淳・近澤心・藤原健治・濱田信生・青木元・高木朗充・山本哲也・林豊・金尾政紀・山下幹也・清水洋・渡邉篤志・是永将宏・大倉敬宏・吉川慎・池田さや香・井口正人・為栗健・八木原寛・平野舟一郎

地震研究所彙報 81 巻 ( 1 ) 頁： 71-94 2006年

GPS measurement of coseismic displacement in Aceh province after the 2004 Aceh-Andaman earthquake Investigation Report of 2004 Northern Sumatra Earthquakes (part 2)

M. Irwan, Y. Ohota, D. Darmawan, H. Andreas, H. Z. Abidin, M. A. Kusuma, D. Sugiyanto, Agustan, T. Ito, T. Tabei and F. Kimata

Investigation Report of 2004 Northern Sumatra Earthquakes (part 2), Graduate School of Environmental Studies, Nagoya University 頁： 103-108 2006年

石英管伸縮計で観測された低周波地震活動に関する歪変化

仮屋新一, 伊藤武男, 山内常生, 木股文昭

東濃地震科学研究所報告 20 巻頁： 185-196 2006年

スマトラのＧＰＳ観測から見えてきた滑り分布：スマトラアチェでのＧＰＳ観測から見えてきた2004年アチェ・アンダマン地震の滑り分布

木股文昭・伊藤武男・太田雄策・メイラノイルワン・田部井隆雄

月刊地球、スマトラ地震特集号頁： 86-94 2006年

GPSデータに基づくスマトラ沖地震の余効変動

太田雄策, Meilano Irwan, 伊藤武男, 木股文昭, 田部井隆雄, Didik Sugiyant

地震学会ニュースレター 7 巻頁： 21-22 2005年

スマトラ沖地震のGPS観測

伊藤武男, 木股文昭, イルワンメイラノ, 太田雄策, 田部井隆雄

地震学会ニュースレター 5 巻頁： 15-17 2005年

変動地形に基づく2004年中越地震の断層モデル査読有り

渡辺満久, 鈴木康弘, 伊藤武男

地震 2 巻 ( 58 ) 頁： 297－307 2005年

Nonlinear multidimensional scaling and visualization of earthquake clusters over space, time and feature space 査読有り

W. Dzwinel, D.A. Yuen, K. Boryczko, Y. Ben-Zion, S. Yoshioka, and T. Ito

Nonlinear Processes in Geophysics 12 巻頁： 117－128 2005年

稠密GPS観測による2003年十勝沖地震の余効変動観測

笠原稔, 高橋浩晃, 岡崎紀俊, 中尾茂, 鷺谷威, 伊藤武男, 大谷文夫, 佐藤一敏, 藤田安良, 橋本学, 細善信, 加藤照之, 飯沼卓史, 福田淳一, 松島健, 河野裕希

月刊地球, 号外 49 巻頁： 105-111 2005年

御嶽山群発地震域において精密水準測量から検出された地盤の隆起変動 2002年4月-2004年4月

木股文昭,村瀬雅之宮,島力雄,Dudy Darmawan,伊藤武男,高野和友,太田雄策,Irwan Meirano,Herri Anderson,David Solim,Fauzan Ibrahim,小山悦郎,辻浩,高山鐵郎,内田和也,岡田純

東濃地震科学研究所報告書 14 巻頁： 7-18 2004年5月

*Spatiotemporal distribution of interplate coupling in southwest Japan from inversion of geodetic data 査読有り

T. Ito, M. Hashimoto

Journal of Geophysical Research 頁： 2002JB002358RR 2004年

GPS observation of the first month of postseismic crustal deformation associated with the 2003 Tokachi-oki earthquake (Mjma 8.0), off southeastern Hokkaido, Japan 査読有り

H. Takahashi, S. Nakao, N. Okazaki, J. Koyama, T. Sagiya, T. Ito, F. Ohya, K. Sato, Y. Fujita, M. Hashimoto, Y. Hoso, T. Kato, T. Iinuma, J. Fukuda, T. Matsushima, Y. Kohno, and M. Kasahara

Earth Planets Space 56 巻頁： 377-382 2004年

Ground uplift detected by precise leveling in the Ontake earthquake swarm area, central Japan in 2002-2004 査読有り

Kimata F, Miyajima R, Murase M, Darwaman D, Ito T, Ohata Y, Irwan M, Takano K, Ibrahim F, Koyama E, Tsuji H, Takayama T, Uchida K, Okada J, Solim D, Anderson H

EARTH PLANETS AND SPACE 56 巻 ( 12 ) 頁： E45-E48 2004年

日本列島の移動性地殻変動

伊藤武男, 橋本学

月刊地球, 25, 2, 114-118, 2003. 25 巻 ( 2 ) 頁： 114-118 2003年

A model of dyke intrusion near Miyake, Nii and Kozu Islands in 2000 査読有り

T. Ito, S. Yoshioka

Tectonophysics 359 巻頁： 171-187 2002年

Interplate coupling in northeast Japan deduced from inversion analysis of GPS data 査読有り

T. Ito, S. Yoshioka and S. Miyazaki

Earth and Planetary Science Letters 176 巻頁： 117-130 2000年

Interplate coupling in southwest Japan deduced from inversion analysis of GPS data 査読有り

T. Ito, S. Yoshioka and S. Miyazaki

Physics of the Earth and Planetary Interiors 115 巻頁： 17-34 1999年

ＧＰＳデータのインヴァージョン解析から推定した東北日本におけるプレート間カップリングの推定

伊藤武男, 吉岡祥一, 宮崎真一

月刊地球, 25, 158-165, 1999. 25 巻頁： 158-165 1999年

ＧＰＳデータを用いた西南日本におけるプレート間カップリングの推定

吉岡祥一, 伊藤武男, 宮崎真一

月刊地球 21 巻頁： 197-204 1999年

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