A5026810720- earthquake and tectonic studies
- Seismology and Earthquake Studies
- Seismic Waves and Analysis
- Seismic Imaging and Inversion Techniques
- High-pressure geophysics and materials
- Earthquake Detection and Analysis
- Methane Hydrates and Related Phenomena
- Geophysics and Sensor Technology
- Cryospheric studies and observations
- Geological and Geochemical Analysis
- Geological Modeling and Analysis
- Landslides and related hazards
- Geophysics and Gravity Measurements
- Geomagnetism and Paleomagnetism Studies
- Distributed and Parallel Computing Systems
- Geological Studies and Exploration
- Advanced Computational Techniques and Applications
- Hydrocarbon exploration and reservoir analysis
- Winter Sports Injuries and Performance
- Geology and Paleoclimatology Research
- Geochemistry and Geologic Mapping
- Geological and Geophysical Studies
- Climate change and permafrost
- Geophysical and Geoelectrical Methods
- Oceanographic and Atmospheric Processes
Japan Agency for Marine-Earth Science and Technology
2015-2024
Hot Springs Research Institute of Kanagawa Prefecture
2021
British Oceanographic Data Centre
2018
Yokohama City University
2000-2014
National Defense Academy of Japan
1999-2014
Incorporated Research Institutions For Seismology
2008
The University of Tokyo
1983-1997
Association for the Development of Earthquake Prediction
1995
Princeton University
1993
Earthquake Engineering Research Institute
1989-1992
Large scientific applications deployed on current petascale systems expend a significant amount of their execution time dumping checkpoint files to remote storage. New fault tolerant techniques will be critical efficiently exploit post-petascale systems. In this work, we propose low-overhead high-frequency multi-level technique in which integrate highly-reliable topology-aware Reed-Solomon encoding three-level scheme. We hide the using one Fault-Tolerance dedicated thread per node. implement...
Research Article| January 03, 2019 Discrimination of Seismic Signals from Earthquakes and Tectonic Tremor by Applying a Convolutional Neural Network to Running Spectral Images Masaru Nakano; Nakano aR&D Center for Earthquake Tsunami, Japan Agency Marine‐Earth Science Technology (JAMSTEC), Kanazawa, Yokohama 236‐0001, Japan, mnakano@jamstec.go.jp, horit@jamstec.go.jp Search other works this author on: GSW Google Scholar D. Sugiyama; Sugiyama bCenter Earth Information Technology,...
We use 1944 processors of the Earth Simulator to model seismic wave propagation resulting from large earthquakes. Simulations are conducted based upon spectral-element method, a high-degree finite-element technique with an exactly diagonal mass matrix. very mesh 5.5 billion grid points (14.6 degrees freedom). include full complexity Earth, i.e., three-dimensional wave-speed and density structure, 3-D crustal model, ellipticity as well topography bathymetry. A total 2.5 terabytes memory is...
Abstract Long-period ground motions in plain and basin areas on land can cause large-scale, severe damage to structures buildings have been widely investigated for disaster prevention mitigation. However, such ocean-bottom are poorly studied because of their relative insignificance uninhabited the lack strong-motion data. Here, we report evidence development long-period (10–20 s) using deep The waveforms spectrograms demonstrate prolonged amplified that inconsistent with attenuation patterns...
Some of the most dramatic effects climate change have been observed in Earth's polar regions. In Greenland, ice loss from Greenland sheet has accelerated recent years [ Shepherd et al ., 2012]. Outlet glaciers are changing their behavior rapidly, with many thinning, retreating, and accelerating Joughin 2004]. The weighing on crust mantle below allowed both to rebound, resulting high rock uplift rates Bevis Changes cover meltwater production influence sea level feedbacks; they expected...
The resolving power of polarization data compared with that phase is investigated by employing both synthetic and observed sets, using the linear relationship between velocity perturbation or anomaly. In order to investigate intrinsic differences data, a test first undertaken white noise model sufficiently uniform coverage ray paths. This shows can retrieve higher-order heterogeneities degrees up 20 almost completely, despite damping smoothing effects, whilst only those lower than 8...
We analyze broadband seismograms for magnitude 5 to 7 earthquakes which occurred in and around Japan develop a technique determine moment from first-arrival P waveforms. theoretically consider displacements of the -wave portion on seismograph record as an approximate source time function integrate them obtain scalar moments at each station. show that combination multiple records will give good estimation without correcting mechanism. This is quite simple robust, so it be effective rapid...
A large Mw = 8.1 earthquake occurred off southeast coast of Antarctica near the Balleny Island region on March 25, 1998. We inverted teleseismic body-wave records to determine rupture pattern using an iterative deconvolution method. The source parameters obtained are: centroid depth=20km, (strike, dip, rake)= (282, 83, −1), seismic moment M0 1.6 × 1021 Nm (Mw 8.1), length L 200 km, and average slip D 4.4 m. This in mid-plate but there has been no reports such earthquakes this region....
Abstract The broadband moment magnitude Mwp (Tsuboi, et al., 1995) allows for the effective determination of earthquake by using P waveforms. It was developed to determine shallow earthquakes around Japanese Islands early tsunami warnings. Tsuboi al. (1995) demonstrated that shows good agreement with Mw from Harvard centroid tensor (CMT) solutions. In present study, we show is also applicable deep and recorded at teleseismic distances. proves be useful quick, accurate size estimates both...
We present a method for inverting laterally heterogeneous earth structure with respect to starting model. Our makes it possible perform iterative linearized inversion of seismic waveform data; in contrast, previous methods have been limited single iteration which the entire part model is treated as perturbation. demonstrate feasibility our approach by low angular order (s = 1 s 4) upper mantle model, using data from IDA network.
The "Arctic" region, where the North Pole occupies center of Arctic Ocean, has been affecting environmental variation Earth from geological time to present. However, seismic activities in area are not adequately monitored. Therefore, by conducting long term monitoring phenomenon as sustainable parameters, our understanding both tectonic evolution and dynamic interaction between cryosphere geosphere surface layers will increase. In this paper, association seismicity structure particularly...
In contrast to previous work, which treats the Earth's lateral heterogeneity as an infinitesimal perturbation a spherically symmetrical starting model, we conduct iterative linearized waveform inversion for laterally heterogeneous structure. We use Direct Solution Method (DSM) (Geller et al. 1990a) calculate synthetic seismograms and their partial derivatives earth model. invert surface-wave data from IDA GEOSCOPE networks. expand of rigidity in spherical harmonics up angular order number 8...
The mantle beneath the Japanese islands is complex because of subduction Pacific and Philippine Sea plates deformation associated with it. Detection seismic anisotropy should be useful for understanding processes occurring in such mantle. Here we resolve wedge from that underlying subducted slab using a large number measurements shear wave splitting family core‐reflected phases: ScS , sScS 2, 2. changes sharply across volcanic front. On side front vertically propagating polarized fast...
We present high-performance simulations of global seismic wave propagation with an unprecedented accuracy 1.2 s period for a realistic three-dimensional Earth model using the spectral element method on K computer. Our use total 665.2 billion grid points and resolve 1.8 trillion degrees freedom. To realize these large-scale computations, we optimize widely used community software code to efficiently address all hardware parallelization, especially thread-level parallelization solve bottleneck...
Basal conditions of the Greenland Ice Sheet (GrIS) are a key research topic in climate change studies. The recent construction seismic network has provided new opportunity for direct, real-time, and continuous monitoring GrIS. Here we use ambient noise surface wave data from stations all over 4.5-year period to detect changes Rayleigh-wave phase velocity between station pairs. We observe clear seasonal long-term many pairs, propose plausible mechanism these changes. Dominant factors driving...
We have found two pairs of earthquake doublets closely located antipodally on one diametral axis between Tonga‐Algeria, and several other events axes. These show significant correlation, exhibit seismic phases traversing the Core that cannot be explained by a standard radial Earth model such as PREM. The antipodal waveform data are highly variable observed variability waveforms indicates global variations in structure above below Inner‐Outer boundary region. evidence for regional...
<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> The International Federation of Digital Seismographic Networks (FDSN) is a non-governmental organization formed by institutions dedicated to seismological research and seismic monitoring. FDSN successful complement the Seismological Centre (ISC) in pursuing more than century old tradition global data exchange. main goal production dissemination waveform from high fidelity observatories. 65...
Tsunami earthquake produces anomalously strong tsunamis for their surface wave magnitude. To issue accurate early tsunami warnings earthquakes, it is critical to identify them as tsunamigenic events possible. Here we show that a pulse width of P ‐wave, which use calculate broadband moment magnitude M wp , gives estimates source duration time. We find may 1992 Nicaragua possible by using combination both and the duration. Our result suggests will provide an effective tool even earthquakes have long