Diagnosing Source Geometrical Complexity of Large Earthquakes     

L. Rivera  H. Kanamori 《Pure and Applied Geophysics》2014,171(10):2819-2840

We investigated the possible frequency dependence of the moment tensor of large earthquakes by performing W phase inversions using teleseismic data and equally-spaced narrow, overlapping frequency bands. We investigated frequencies from 0.6 to 3.8 mHz. Our focus was on the variation with frequency of the scalar moment, the amount of non-double-couple, and the focal mechanism. We applied this technique to 30 major events in the period 1994–2013 and used the results to detect source complexity. Based on the results, we classed them into three groups according to the variability of the source parameters with frequency: simple, complex and intermediate. Twelve of these events fell into the simple category: Bolivia-1994, Kuril-1994, Sanriku-1994, Antofagasta-1995, Andreanoff-1996, Peru-2001, Sumatra-2004, Sumatra-2005, Tonga-2006, Sumatra-2007, Japan-2011, and the recent Sea of Okhotsk-2013. Seven exhibited significant complexity: Balleny-1998, Sumatra-2000, Indian Ocean-2000, Macquarie Island-2004, Sichuan-2008, and Samoa-2009. The remaining 11 events showed a moderate degree of complexity. Here, we discuss the results of this study in light of independent observations of source complexity, made by various investigators.  相似文献   

Analysis software for upper atmospheric data developed by the IUGONET project and its application to polar science     

Yoshimasa Tanaka  Atsuki Shinbori  Tomoaki Hori  Yukinobu Koyama  Shuji Abe  Norio Umemura  Yuka Sato  Manabu Yagi  Satoru UeNo  Akiyo Yatagai  Yasunobu Ogawa  Yoshizumi Miyoshi 《极地研究(英文版)》2013,(4):231-240

To comprehensively understand the Arctic and Antarctic upper atmosphere, it is often crucial to analyze various data that are obtained from many regions. Infrastructure that promotes such interdisciplinary studies on the upper atmosphere has been developed by a Japanese inter-university project called the Inter-university Upper atmosphere Global Observation Network （1UGONET）. The objective of this paper is to describe the infrastructure and tools developed by IUGONET. We focus on the data analysis software. It is written in Interactive Data Language （IDL） and is a plug-in for the THEMIS Data Analysis Software suite （TDAS）, which is a set of IDL libraries used to visualize and analyze satellite- and ground-based data. We present plots of upper atmospheric data provided by IUGONET as examples of applications, and verify the usefulness of the software in the study of polar science. We discuss IUGONET＇s new and unique developments, i.e., an executable file of TDAS that can run on the IDL Virtual Machine, IDL routines to retrieve metadata from the IUGONET database, and an archive of 3-D simulation data that uses the Common Data Format so that it can easily be used with TDAS.  相似文献   

Model Space Exploration for Determining Landslide Source History from Long-Period Seismic Data     

Juan Zhao  Laurent Moretti  Anne Mangeney  Eléonore Stutzmann  Hiroo Kanamori  Yann Capdeville  Eliza S. Calder  Clément Hibert  Patrick J. Smith  Paul Cole  Anne LeFriant 《Pure and Applied Geophysics》2015,172(2):389-413

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International Pellet Watch: Global monitoring of persistent organic pollutants (POPs) in coastal waters. 1. Initial phase data on PCBs, DDTs, and HCHs   总被引：1，自引：0，他引：1  

Yuko Ogata  Kaoruko Mizukawa  Satoru Iwasa  Yukie Mato  Keiji Okuda  Michio Murakami  Ruchaya Booyatumanondo  Le Quang Dung  Carlos Miguez  Charles Moore  Steven Weerts  Erick Burres  Michael Van Velkenburg  Richard C. Lang  Brenda Danner  Richard C. Thompson 《Marine pollution bulletin》2009,58(10):1437-1446

Samples of polyethylene pellets were collected at 30 beaches from 17 countries and analyzed for organochlorine compounds. PCB concentrations in the pellets were highest on US coasts, followed by western Europe and Japan, and were lower in tropical Asia, southern Africa and Australia. This spatial pattern reflected regional differences in the usage of PCBs and was positively correlated with data from Mussel Watch, another monitoring approach. DDTs showed high concentrations on the US west coast and in Vietnam. In Vietnam, DDT was predominant over its metabolites (DDE and DDD), suggesting the principal source may be current usage of the pesticide for malaria control. High concentrations of pesticide HCHs were detected in the pellets from southern Africa, suggesting current usage of the pesticides in southern Africa. This study demonstrates the utility and feasibility of the International Pellet Watch approach to monitor POPs at a global scale.  相似文献   

Does heavy oil pollution induce bacterial diseases in Japanese flounder Paralichthys olivaceus?   总被引：1，自引：1，他引：0  

Jun-Young Song  Kei Nakayama  Yasunori Murakami  Sung-Ju Jung  Myung-Joo Oh  Satoru Matsuoka  Hidemasa Kawakami  Shin-Ichi Kitamura   《Marine pollution bulletin》2008,57(6-12):889

As basic research for the effect of heavy oil on the fish immune system, in this study, the number of leukocyte was counted in Japanese flounder Paralichthys olivaceus, after exposure to heavy oil at a concentration of 30 g/8 L for 3 days. To compare the numbers of bacteria in the skin mucus between oil-exposed and control fish, viable bacteria were enumerated by counting colony forming unit (CFU). Compared with 5.79 ± 1.88 × 10⁷ leukocytes/mL in the controls, the exposed fish demonstrated higher counts, averaging 1.45 ± 0.45 × 10⁸ cells/mL. The bacterial numbers of control fish were 4.27 ± 3.68 × 10⁴ CFU/g, whereas they were 4.58 ± 1.63 × 10⁵ CFU/g in the exposed fish. The results suggest that immune suppression of the fish occurred due to heavy oil stressor, and bacteria could invade in the mucus, resulting in the increasing leukocyte number to prevent infectious disease.  相似文献   

Variability in the Relative Penetration of Ultraviolet Radiation to Photosynthetically Available Radiation in Temperate Coastal Waters, Japan   总被引：1，自引：0，他引：1  

Victor S. Kuwahara  Tatsuki Toda  Koji Hamasaki  Tomohiko Kikuchi  Satoru Taguchi 《Journal of Oceanography》2000,56(4):399-408

UVR and PAR wavelengths are attenuated to different extents within the water column, causing variations in spectral composition with depth. The present investigation (a) describes the variability of UVR and PAR penetration at a station in the temperate coastal waters of Sagami Bay and determines (b) the characteristics of relative UVR penetration to the euphotic zone. Examination of the seasonal irradiance profile measurements indicated eight measurements displaying two distinct attenuation coefficients (K _d) for specific UVR wavelengths and PAR. The two attenuation coefficients observed from specific wavelengths in the water column may be caused not only by chlorophyll pigments, but also by dissolved organic material in the upper layer. The 1% depth of surface UVR at 305, 320, 340, and 380 nm averaged 10.8 ± 5.7, 14.9 ± 9.5, 19.8 ± 12.1, and 30.4 ± 17.6 m, respectively. The depth of euphotic layer displayed less variability averaging 62 ± 15 m throughout the entire study. Relative UVR penetration within the euphotic zone averaged 17.8 ± 8.1, 22.9 ± 10, 30.5 ± 13.8, and 46 ± 46.9% for 305, 320, 340, and 380 nm, respectively. A large variation of the relative transmission of UVR within the euphotic zone was found although the spectral composition was relatively stable in the air throughout the study.  相似文献   

Shallow subduction zone earthquakes and their tsunamigenic potential   总被引：3，自引：0，他引：3  

J. Polet  & H. Kanamori 《Geophysical Journal International》2000,142(3):684-702

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Permeability measurements of natural and experimental volcanic materials with a simple permeameter: Toward an understanding of magmatic degassing processes     

Shingo Takeuchi  Satoru Nakashima  Akihiko Tomiya 《Journal of Volcanology and Geothermal Research》2008

Permeability measurement of quenched volcanic porous materials is an important approach to understand permeability development and degassing of vesicular silicic magmas. In this study, we developed a gas permeameter to measure permeability of natural samples and experimental products. The permeameter has broad measurement ranges of pressure difference (10¹–10⁵ Pa) and gas-flow rate (10^− 9–10^− 5 m³/s). These ranges enable us to measure viscous permeability in the range of 10^− 17–10^− 9 m² for 1 centimeter-scale samples, using the Forchheimer equation, which includes the inertial effect of gas flow permeating through the samples. In addition, we improved the procedure for performing permeability measurements of mm-sized products of decompression experiments. Although a previous study reported the first permeability data for vesicular silicic glass products of decompression experiments, we found an overestimation in their permeability data due to problems in sample preparation, especially for very low permeability samples. Our improved measurements give lower permeability values than those of Takeuchi et al. (2005)(Takeuchi, S., Nakashima, S., Tomiya, A., Shinohara, H., 2005. Experimental constraints on the low gas permeability of vesicular magma during decompression. Geophys. Res. Lett., 32, L10312 doi:10.1029/2005GL022491).  相似文献   

A New Solar Imaging System for Observing High-Speed Eruptions: <Emphasis Type="Italic">Solar Dynamics Doppler Imager</Emphasis> (SDDI)     

Kiyoshi Ichimoto  Takako T. Ishii  Kenichi Otsuji  Goichi Kimura  Yoshikazu Nakatani  Naoki Kaneda  Shin’Ichi Nagata  Satoru UeNo  Kumi Hirose  Denis Cabezas  Satoshi Morita 《Solar physics》2017,292(4):63

A new solar imaging system was installed at Hida Observatory to observe the dynamics of flares and filament eruptions. The system (Solar Dynamics Doppler Imager; SDDI) takes full-disk solar images with a field of view of \(2520~\mbox{arcsec} \times 2520~\mbox{arcsec}\) at multiple wavelengths around the \(\mathrm{H}\alpha\) line at 6562 Å. Regular operation was started in May 2016, in which images at 73 wavelength positions spanning from \(\mathrm{H}\alpha -9~\mathring{\mathrm{A}}\) to \(\mathrm{H}\alpha +9~\mathring{\mathrm{A}}\) are obtained every 15 seconds. The large dynamic range of the line-of-sight velocity measurements (\({\pm}\,400~\mbox{km}\,\mbox{s}^{-1}\)) allows us to determine the real motions of erupting filaments in 3D space. It is expected that SDDI provides unprecedented datasets to study the relation between the kinematics of filament eruptions and coronal mass ejections (CME), and to contribute to the real-time prediction of the occurrence of CMEs that cause a significant impact on the space environment of the Earth.  相似文献   

Short-Term Stability Evaluation of an Embankment Constructed on Marine Clay Foundation at Kobe Airport     

Minsu Jung  Satoru Shibuya 《Marine Georesources & Geotechnology》2016,34(1):10-20

This article introduces the application of a stability analysis method that accounts for strength anisotropy on the embankment constructed at the Kobe airport. Shear strength anisotropy is induced by the in-situ state of stress along a potential slip surface of the embankment. In addition, the effects of the shearing rate on the undrained shear strength of the marine clay are examined in detail based on the results of a series of constant-volume direct shear box (DSB), triaxial compression (TC), and triaxial extension (TE) tests varying shearing rates. The most critical slip surface was selected from the deterministic slope stability analysis using unconfined compression tests of undisturbed clay samples from the field. For the most critical slip surface, the potential factor of safety of the embankment is estimated to be within the range of 1.21 to 1.28, as indicated by the results of the stability analyses using the strengths obtained from the DSB, TC, and TE tests and varying shearing rates.  相似文献