A5027507330- Geophysics and Sensor Technology
- Seismic Waves and Analysis
- Pulsars and Gravitational Waves Research
- Gamma-ray bursts and supernovae
- High-pressure geophysics and materials
- Seismology and Earthquake Studies
- earthquake and tectonic studies
- Advanced Measurement and Metrology Techniques
- Astrophysical Phenomena and Observations
- Geophysics and Gravity Measurements
- Dark Matter and Cosmic Phenomena
- Magnetic confinement fusion research
- Statistical and numerical algorithms
- Hydraulic and Pneumatic Systems
- Structural Health Monitoring Techniques
- Geomechanics and Mining Engineering
- Vehicle Dynamics and Control Systems
- Advanced Sensor and Control Systems
- Earthquake Detection and Analysis
- Cosmology and Gravitation Theories
- Seismic Imaging and Inversion Techniques
- Advanced Electrical Measurement Techniques
- Geotechnical and Geomechanical Engineering
- Software System Performance and Reliability
- Inertial Sensor and Navigation
The University of Tokyo
2001-2024
Association for the Development of Earthquake Prediction
2024
Earthquake Engineering Research Institute
2016-2019
California Institute of Technology
2004
A laser strainmeter with a 1500-m baseline was constructed at an underground site in Kamioka, Gifu Prefecture, Japan, and has been operating since August 2016. The interferometer measures the change distance between two retroreflectors housed vacuum chambers separation of 1500 m. are fixed to ground tunnel KAGRA gravitational wave telescope. high-frequency-stabilized is used as light source; it achieves Allan variance 3 × 10−13. Since operations began, motions large amplitude timescale...
Long-term observations conducted with large arrays of tiltmeters deployed in ocean-bottom boreholes, on the seafloor and other hazardous regions are expected to provide rich information useful geosciences, social engineering, resource monitoring applications. To facilitate such observations, we designed built a compact, highly sensitive tiltmeter sufficient performance, comparable that much larger instruments difficult operate target locations. The new is suitable for requiring multiple...
Abstract In this study, we detected the horizontal ground strains induced by atmospheric Lamb wave emitted from 2022 eruption of Tonga–Hunga Ha’apai undersea volcano, at an underground observatory in Kamioka, Japan. The observed were range $${10}^{-11}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mo>-</mml:mo> <mml:mn>11</mml:mn> </mml:msup> </mml:math> – $${10}^{-10}$$ and measured precisely using a 1500-m laser...
Abstract Temporary slip speed increases with durations of 1–3 h were identified during short-term slow events in records borehole and laser strainmeters the Tokai region, Japan. They found by searching for peaks correlation coefficients between stacked strain data ramp functions rise times 1 2 h. Although many steps considered due to noise, some occurred simultaneous activation deep tectonic tremors shared source areas tremors. From 2016 2022, we observed five coincidence locations Those...
KAGRA is a cryogenic interferometric gravitational wave detector currently under construction in the Kamioka mine Japan. Besides test masses, will also rely on room temperature optics which hang at bottom of vibration isolation chains. The payload each chain comprises an optic, system to align it, and active feedback damp resonant motion suspension itself. This article describes performance prototype that was assembled tested vacuum TAMA300 site NAOJ Mitaka, Tokyo. We describe mechanical...
We have developed a novel absolute distance meter (ADM) for determining coseismic strain steps and analysed far-field crustal deformation caused by earthquakes. By measuring the optical resonant frequency of 100-m-long cavity in relation to an accurate time standard, can be determined with resolution 2 × (10−9–10−10); measurements ensure detection changes before after earthquake, even when encountering large seismic waves that often hinder relative measurements. The proposed system,...
A highly accurate two-color interferometer with automatic correction of the refractive index air was developed for crustal strain observation. The interferometer, which can measure a geometrical distance approximately 70 m, relative resolution 2 × 10−9, clearly detected change in due to earth tides spite optical measurement air. Moreover, large quake an earthquake could be observed without disturbing measurement. We demonstrated advantages geodetic
Long-term observations conducted with large arrays of tiltmeters deployed in ocean bottom boreholes, on the seafloor, are expected to provide rich information useful geosciences, social engineering, resource monitoring, and other applications. To facilitate such observations, we designed built a compact, highly sensitive tiltmeter sufficient performance, comparable that much larger instruments difficult operate target locations. This paper describes its key technologies, including compact...
Abstract In this study, we detected the horizontal ground strains, induced by atmospheric Lamb wave emitted from 2022 eruption of Tong–Hunga Ha’apai undersea volcano, at an underground observatory in Kamioka, Japan. The observed strains were range 10 -11 to -10 and precisely measured using a 1500-m laser strainmeter with high resolution order -12 . was constructed tunnel KAGRA gravitational-wave telescope. Our observations showed that strain pressure clearly correlated, resulting regression...