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Earthquake Science 2010年第4期23卷 301-308页

作者： Guangyu Fu Wenke Sun yoichi fukuda Shanghua Gao Takashi Hasegawa Institute of Earthquake Science China Earthquake Administration Beijing 100036 China Department of Geophysics Graduate School of Science Kyoto University Kyoto 606-8502 Japan Laboratory of Computational Geoclynamics Graduate University of Chinese Academy of Sciences Beijing 100049 China

Recently, effects of Earth＇s curvature and radial heterogeneity on coseismic deformations are often investi- gated based on the 2004 Sumatra earthquake. However, such effects are strongly related to earthquake types. As a low dip angle event, the 2004 Sumatra earthquake is not a good seismic case for such a topic since the effects for moderate dip angle events are much bigger. In this study, the half-space and spherical dislocation theories are used, respectively, to calculate co- seismic displacements caused by the 2008 Wenchuan earthquake and the 2004 Sumatra earthquake. Effects of Earth＇s curva- ture and stratification are investigated through the discrepancies of results calculated using the two dislocation theories. Re- sults show that the effects of Earth＇s curvature and stratification for the 2008 Wenchuan earthquake are much larger than those for the 2004 Sumatra earthquake. Ignoring the effects will cause errors up to 100%-200% in far field displacements for a moderate dip angle event like the 2008 Wenchuan earthquake. Such great effects are much bigger than those conclusions of previous studies. Besides, comparison with observations verifies that spherical dislocation theories yield better results than half-space ones in far fields.

关键词： coseismic displacement dislocation theory Earth model

Effects of Gaussian filter in processing GRACE data: Gravity rate of change at Lhasa,southern Tibet

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Science China Earth Sciences 2011年第9期54卷 1378-1385页

作者： SUN WenKe HASEGAWA Takashi ZHANG XinLin fukuda yoichi SHUM C. K. WANG Lei Key Laboratory of Computational Geodynamics Graduate University of Chinese Academy of Sciences Beijing 100049 China Department of Geophysics Kyoto University Japan Earthquake Research Institute The University of Tokyo Japan Division of Geodetic Science School of Earth Sciences The Ohio State University OH 43210-1398 USA

In this paper, the spatial gravity distribution over Tibetan Plateau and the gravity rate of change at Lhasa for different Gaussian filter radii are computed using GRACE data. Results show that the estimate of the gravity rate of change is spatialradius-dependent of the Ganssian filter. The GRACE-estimated gravity rate of change agrees well with the surface measured one. In other words, the GRACE-estimated gravity rate of change has a limited value as that obtained by surface measurement when the spatial filter radius reaches zero. Then numerical simulations are made for different spatial radii of the Gaussian filter to investigate its behaviors when applied to surface signals. Results show that the estimate of a physical signal is filter-radius dependent. If the computing area is equal to or less than the mass area, especially for a uniformly distributed mass, the estimate gives an almost correct result, no matter what filter radius is used. The estimate has large error because of the signal leakage caused by harmonic truncation if the computing area is much bigger than the mass distribution （or inverse for a small mass anomaly）. If a mass anomaly is too small, it is difficult to recover it from space observation unless the filter radius is extremely small. If the computing point （or area） is outside the mass distribution, the estimated result is almost zero, particularly for small filter radii. These properties of the Gaussian filter are helpful in applying GRACE data in different geophysical problems with different spatial position and geometrical size. We further discuss physical sources causing the scalar gravity change at Lhasa. Discussions indicate that the gravity rate of change at Lhasa is not caused by the present-day ice melting （PDIM）（or Little Ice Age, LIA） effect because no ice melting occurs in Lhasa city and nearby. The gravity rate of change is attributable mainly to tectonic deformation associated with the Indian Plate collision. Simultaneous surf

关键词： gravity change GRACE Gaussian filter Tibetan Plateau Lhasa

Co-seismic strain changes of Wenchuan Mw7.9 earthquake recorded by borehole strainmeters on Tibetan plateau

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Geodesy and Geodynamics 2011年第3期2卷 42-49页

作者： Fu Guangyu Shen Xuzhang fukuda yoichi Gao Shanghua Yoshii Satoshi Institute of Earthquake Sciences China Earthquake Administration Beijing 100036 China Key Laboratory of Computational Geodynamics Chinese Academy of Sciences Belting 100049 China Lanzhou Institute of Seismology China Earthquake Administration Lanzhou 730000 China Department of Geophysics Graduate School of Science Kyoto University Kyoto 6068502 Japan

Co-seismic strain changes of the Wenchuan MwT. 9 earthquake recorded with three four-component borehole strainmeters showed NW-SE and roughly EW extensions, respectively, at two locations in the interior and northern part of Tibetan plateau, and NS shortening at a location south of the epicenter, in agreement with the tectonic stress field of this region retical values obtained with half-space effects, such as local crustal structure The observed values of as much as 10-7 are, however, larger than theo- and spherical-earth dislocation theories, implying the existence of other and initial stress.

关键词： Wenchuan MwT. 9 earthquake co-seismic strain changes Tibetan plateau dislocation theory

Observation and Data Archiving System of a Superconducting Gravimeter at Syowa Station, Antarctica

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International Journal of Geosciences 2015年第10期6卷 1116-1126页

作者： Yuichi Aoyama Hiroshi Ikeda Hideaki Hayakawa Koichiro Doi yoichi fukuda Kazuo Shibuya National Institute of Polar Research Tokyo Japan Department of Polar Science SOKENDAI (The Graduate University for Advance Studies) Tokyo Japan Research Facility Center for Science and Technology University of Tsukuba Tsukuba Japan Graduate School of Science Kyoto University Kyoto Japan

A superconducting gravimeter (SG, model TT70#016, GWR Instruments) was deployed for the first time in Antarctica in 1992 at Syowa Station. Observations began in April 1993. Although the SG was equipped with a 10 K cryocooler, its liquid helium (LHe) required refilling twice a year to maintain its superconducting state. The LHe was produced by a separate helium liquefier. After continuous gravity measurement with the SG for 11 years, it was replaced by a second SG (CT#043) with a 4 K cryocooler in December 2003 in order to reduce loads of person in charge for LHe production. Because the manufacturer could not supply a replacement 4 K cryocooler, this SG ceased measurement in November 2009. In January 2010, a new superconducting gravimeter (OSG#058) was installed and had recorded high-quality gravity time series with data acquired every second for more than five years without interruption. Because the personal computer (PC) controlling the observation and data acquisition is connected with PCs in Japan through an Intelsat satellite communication link, we can check the status of observations in real time. It is also possible to fix remotely certain problems with the gravimeter. The observed gravity data are transferred daily to a data server in Japan. Also included in the upload are diagnostic data of the gravimeter such as the temperature of the coldhead and environmental data such as atmospheric pressure. Plots of the daily data are publicly available. The raw data with a 1 s sampling interval are also released to registered researchers. The released gravity time series along with the environmental data are greatly useful for investigating solid earth dynamics especially in the long period bands. We provide necessary information to use these long-range data sets.

关键词： Superconducting Gravimeter Remote Observation Monitoring High Quality Data Antarctica

Field measurements of absolute gravity in East Antarctica

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Advances in Polar Science 2013年第4期24卷 339-343页

作者： Koichiro Doi Hideaki Hayakawa Takahito Kazama Toshihiro Higashi Shingo Osono yoichi fukuda Jun Nishijima Yuichi Aoyama Junichi Ueda National Institute of Polar Research The Graduate University for Advanced Studies (SOKENDAI) Aso Volcanological Laboratory Kyoto University Graduate School of Science Kyoto University TerraGrav LLC. GNSS Technologies Inc. Graduate School of Engineering Kyushu University Japan Association of Surveyors

This paper reports the results of field-based absolute gravity measurements aimed at detecting gravity change and crustal displacement caused by glacial isostatic adjustment. The project was initiated within the framework of the 53rd Japanese Antarctic Research Expedition （JARE53）. Absolute gravity measurements, together with GPS measurements, were planned at several outcrops along the Prince Olav Coast and S6ya Coast of East Antarctica, including at Syowa Station. Since the icebreaker Shirase （AGB 5003） was unable to moor alongside Syowa Station, operations were somewhat restricted during JARE53. However, despite this setback, we were able to complete measurements at two sites： Syowa Station and Langhovde. The absolute gravity value at the Syowa Station IAGBN （A） site, observed using an FG-5 absolute gravimeter （serial number 210; FG-5 #210）, was 982 524 322.7＋0.1 ktGal, and the gravity change rate at the beginning of 2012 was -0.26 gGal.a-1. An absolute gravity value of 982 535 584.2~0.7 ktGal was obtained using a portable A-10 absolute gravimeter （serial number 017; A-10 #017） at the newly located site AGS01 in Langhovde.

关键词： absolute gravity field measurement Antarctica A-10 and FG-5 absolute gravimeters GPS JARE

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对人类和环境友好的自动扶梯

中国电梯 2014年第20期25卷 35-37页

作者：伊势洋一坂上满福田俊之行武奇

1引言随着人们对于安全和环境保护边缘问题的关注与日俱增，对于更高安全等级和更少对环境有负面影响的自动扶梯的需求日益高涨。为了满足这些要求，根据“以对人和环境友好的扶梯为目标”的理念，我们以四大支柱为基础设计开发出了新... 详细信息

1引言随着人们对于安全和环境保护边缘问题的关注与日俱增，对于更高安全等级和更少对环境有负面影响的自动扶梯的需求日益高涨。为了满足这些要求，根据“以对人和环境友好的扶梯为目标”的理念，我们以四大支柱为基础设计开发出了新型VX系列自动扶梯：进一步追求安全，关注节能和环保，精心设计可用性，高度精确的故障预防诊断。

关键词：自动扶梯环境友好人类安全等级基础设计环境保护故障预防可用性