A5043196438- earthquake and tectonic studies
- Seismology and Earthquake Studies
- Earthquake Detection and Analysis
- High-pressure geophysics and materials
- Geological and Geochemical Analysis
- Seismic Waves and Analysis
- Seismic Imaging and Inversion Techniques
- Geophysics and Sensor Technology
- Landslides and related hazards
- Seismic Performance and Analysis
- Geological and Tectonic Studies in Latin America
- Neurological disorders and treatments
- Rock Mechanics and Modeling
- Geotechnical and Geomechanical Engineering
- Semiconductor Lasers and Optical Devices
- Methane Hydrates and Related Phenomena
- Granular flow and fluidized beds
- Geoscience and Mining Technology
- Geological and Geophysical Studies
- Advanced MRI Techniques and Applications
- Theoretical and Computational Physics
- Photonic and Optical Devices
- Earthquake and Tsunami Effects
- Dementia and Cognitive Impairment Research
- Hydraulic Fracturing and Reservoir Analysis
The University of Tokyo
2016-2025
Tokyo University of Science
2009-2025
Fujitsu (Japan)
2022-2025
Photonics Electronics Technology Research Association
2022
Graduate School USA
2014-2018
John Wiley & Sons (United States)
2014-2015
Hanover College
2015
Planetary Science Institute
2014
University of Occupational and Environmental Health Japan
2013
IEEE Computer Society
2013
Strong spatial variation of rupture characteristics in the moment magnitude (M(w)) 9.0 Tohoku-Oki megathrust earthquake controlled both strength shaking and size tsunami that followed. Finite-source imaging reveals consisted a small initial phase, deep for up to 40 seconds, extensive shallow at 60 70 continuing lasting more than 100 seconds. A combination dipping fault compliant hanging wall may have enabled large slip near trench. Normal faulting aftershocks area high suggest dynamic...
Seismic energy is distributed across a wide frequency band so that limited bandwidth recording can lead to substantial underestimates of the radiated seismic or introduce an artificial upper bound energy. We estimate adjustment factor account for probable missing and apply it three previously studied data sets with bandwidth. find this adjustment, together accounting possibly events, eliminates much moment dependence found previously. obtain nearly constant ratio moment, 3 × 10 −5 , 1 MPa...
Nonvolcanic tremor is observed in close association with geodetically slow-slip events subduction zones. Accumulating evidence points to these as members of a family slow earthquakes that occur shear slip on the downdip extensions fault zones regime transitional between frictionally locked region above and freely slipping below. By virtue their locations properties, are certain provide new insights into behavior faulting hazard they embody.
We study the mechanism of low frequency earthquakes (LFEs) in Nankai Trough western Shikoku, Japan. Precise locations have previously suggested that they represent shear slip on plate boundary. In this paper we examine these events. Due to signal‐to‐noise ratio, analyze stacked LFE waveforms and compare them with nearby known within subducting Philippine Sea Plate. Analysis both focal using P ‐wave first‐motions moment tensor S indicates LFEs a low‐angle thrust fault dipping northwest,...
Eight slow-slip events over 6 years accommodated up to 50% of the fault slip on Nankai megathrust.
Slow earthquake segmentation The Japan Trench is responsible for disastrous megathrust earthquakes like the 2011 Tohoku-Oki quake. Nishikawa et al. used new observations from S-net ocean-bottom seismic network to map slow earthquakes—disturbances that do not cause ground shaking—along (see Perspective by Houston). They found area ruptured during quake was bounded areas have large numbers of earthquakes. A likely caused rupture cease, an observation important assessing risk future major...
Constitutive laws define the boundary conditions on fault plane and govern many aspects of earthquake failure. Although several constitutive have been formulated based laboratory rock experiments applied to theoretical studies in various fields, no actual relation during a natural has determined. The 1995 Kobe is suitable for detailed kinematic analysis, this enables first evaluation relations earthquake. In study, we determine spatiotemporal slip distribution an assumed by waveform...
We reexamine the scaling of stress drop and apparent stress, rigidity times ratio between seismically radiated energy to seismic moment, with earthquake size for a set microearthquakes recorded in deep borehole Long Valley, California. In first calculations, we assume constant Q solve corner frequency moment. second model spectral nearby events determine same quantities. find that technique, which can account path site effects or nonconstant , yields higher drops, particularly smaller data...
Transient slip events, which occur more slowly than traditional earthquakes, are increasingly being recognized as important components of strain release on faults and may substantially impact the earthquake cycle. Surface‐based geodetic instruments provide estimates overall distribution in larger transients but unable to capture detailed evolution such slip, either time or space. Accompanying some these is a relatively weak, extended duration seismic signal, known nonvolcanic tremor, has...
Deep tremor under Shikoku, Japan, consists primarily, and perhaps entirely, of swarms low‐frequency earthquakes (LFEs) that occur as shear slip on the plate interface . Although is observed at other boundaries, lack cataloged has precluded a similar conclusion about in those locales. We use network autocorrelation approach to detect locate LFEs within recorded three subduction zones characterized by different thermal structures levels interplate seismicity: southwest northern Cascadia, Costa...
[1] We apply empirical Green's function coda-based analysis to four earthquake sequences in Japan that span a magnitude range of 1.8 6.9, measure radiated energy, corner frequency and stress drop. find no systematic dependence apparent or drop on seismic moment for these sequences, they both are log-normally distributed; however, we identify several anomalous events - energetic enervated show sharply different spectral signatures from the rest population. These indicate much variation is...
Deep tectonic tremor occurs at various sites worldwide, and the source characteristics are heterogeneous, even small scales. In this study, sources were determined using data sets of seismic waveforms from locations, some which not well recognized as being a site activity. The regions interest subduction zones Nankai Kyushu, Japan, Cascadia in western North America, Mexico, southern Chile, New Zealand. Tremor locations consistent with geometry subducting plates, depth tends to be shallower...
Recent studies of slow earthquakes along plate boundaries have shown that tectonic tremor, low-frequency earthquakes, very-low-frequency events (VLFEs), and slow-slip (SSEs) often accompany each other appear to share common source faults. However, the processes occurring in shallow part are not well known because seismic observations been limited land-based stations, which offer poor resolution beneath offshore boundaries. Here we use data obtained from seafloor observation networks Nankai...
The strong motion and geodetic data were individually inverted for the source process of 2003 Tokachi-oki, Hokkaido, earthquake with a hypocenter 25 km deep fault plane above subducting Pacific slab. Both results show simple slip distribution single major asperity, but inversion may include trade-off between location rupture time does not have sufficient resolution far slips. We then carred out joint two datasets in order to overcome these weaknesses dataset inversions. resultant still...
Research Article| June 13, 2018 Development of a Slow Earthquake Database Masayuki Kano; Kano aEarthquake Institute, The University Tokyo, 1‐1‐1 Yayoi, Bunkyo‐ku, Tokyo 113‐0032, Japan, babasatoru@eri.u-tokyo.ac.jp, kano@eri.u-tokyo.ac.jp, obara@eri.u-tokyo.ac.jp, maeda@eri.u-tokyo.ac.jp, akiko-t@eri.u-tokyo.ac.jpqNow at Department Geophysics, Graduate School Science, Tohoku University, 6‐3 Aramaki Aza‐Aoba, Aoba‐ku, Sendai, Miyagi 980‐8578, Japan; masayuki.kano.a3@tohoku.ac.jp. Search for...
The scaling law for slow earthquakes, which is a linear relationship between seismic moment and duration, was proposed 15 y ago initiated debate on the difference in physical processes governing vs. fast (ordinary) earthquakes. Based new observations across wide period range, we show that of earthquakes remains valid, but as well-defined upper bound rate ~10 13 Nm/s. large gap moment-rate unfilled. Slow occur near detectability threshold, such are unable to detect deformation events with...
Abstract Distributed Acoustic Sensing (DAS) is a promising technique to improve the rapid detection and characterization of earthquakes. Previous DAS studies mainly focus on phase information but less amplitude information. In this study, we compile earthquake data from two arrays in California, USA, one submarine array Sanriku, Japan. We develop data‐driven method obtain first scaling relation between magnitude. Our results reveal that amplitudes recorded by different regions follow similar...
Earthquakes may seem random, but are often concentrated in some localized areas. Thus, they likely controlled by fault materials and stress heterogeneity, which little understood. Here, we provide high-resolution observations of material heterogeneity the Japan subduction zone through an integration source imaging with numerical simulations. Our results present evidence for localized, anisotropic structures a near-zero Poisson’s ratio medium surrounding 1 to 2 kilometer–sized earthquake...