检索结果-南通市图书馆

Field measurements of absolute gravity in East Antarctica

在线全文

学校读者我要写书评

暂无评论

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

gravity variation before Kunlun mountain pass western M_s=8.1 earthquake

在线全文

学校读者我要写书评

暂无评论

Acta Seismologica Sinica(English Edition) 2003年第3期16卷 304-311页

作者：祝意青王双绪江在森朱桂芝李辉张永志 The Second Crustal Deformation Monitoring Center China Seismological BureauXi'an 710054China The Second Crustal Deformation Monitoring Center China Semsmological BureauXi'an 710054China Center for Analysis and Prediction China Seismological BureauBeijing 100036China Institute of Seismology China Seismological BureauWuhan 430071China

The relation between the gravity variation features and Ms=8.1 earthquake in Qinghai-Xizang monitoring area is analyzed preliminarily, by using spatial dynamic variation results of regional gravity field from absolute gravity and relative gravity observation in 1998 and 2000. The results show that: 1) Ms=8.1 earthquake in Kulun mountain pass western occurred in the gravity variation high gradient near gravit/s high negative variation; 2) The main tectonic deformation and energy accumulation before Ms=8.1 earthquake are distributed at south side of the epicenter; 3) The range of gravity's high negative variation at east of the Ms=8.1 earthquake epicenter relatively coincides with that rupture region according to field geology investigation; 4) gravity variation distribution in high negative value region is just consistent with the second shear strain's high value region of strain field obtained from GPS observation.

关键词： absolute gravity relative gravity Ms=8.1 earthquake tectonic deformation

The gravity field and gravity data reduction across the continental area of Nigeria

在线全文

学校读者我要写书评

暂无评论

Geodesy and Geodynamics 2023年第3期14卷 304-320页

作者： Oluwatimilehin B.Balogun Isaac B.Osazuwa Department of Geosciences Mountain Top UniversityPrayer CityOgun StateNigeria Department of Geophysics Federal UniversityOye-EkitiEkiti StateNigeria

This research presents the variation of the gravity field and associated gravity field components over the continental area of Nigeria to provide data for geoscience research,geodetic and engineering works,aerodynamic studies and deep crustal *** positions and elevations were observed at 58 of the 59 base stations of the Primary gravity Network of Nigeria(PGNN),whose absolute gravity values had been accurately *** absolute gravity values were plotted against their respective positions to reveal the distribution pattern and strength of the gravity field within the study *** gravity values at each base station were generated using the Somigliana's *** free-air gravity and free-air anomaly gravity values were generated with respect to the World Geodetic System 1984(WGS84)ellipsoid using GPS-derived elevation ***,the perturbing potential,free-air gravity with respect to the geoid,and the indirect effects were *** average of the indirect effects was used to adjust the WGS84 gravity formula to produce a gravity formula that better approximates the geoid across the continental area of Nigeria,compatible with the heights measured relative to the geoid,which can serve as a reference for establishing a vertical height *** Bouguer gravity and Bouguer gravity anomalies across Nigeria revealed a“trans-southern gravity high strip”interpreted to be associated with mantle *** new major mega-lineaments related to mantle upwelling were mapped.A batholith province trending NWeSE was delineated,occurring from north central Nigeria to the north western region and containing closures of“Bouguer gravity lows”interpreted as batholiths.A separate closure of“Bouguer gravity low”was detected at Azare,north eastern Nigeria,which may be due to the presence of intrusive granitic *** is recommended that the mantle structure beneath“the trans-southern gravity high strip”,“delineated batholith province”and“isolat

关键词： absolute gravity Continental Nigeria landmass Primary gravity network of Nigeria(PGNN) WGS84 ellipsoid Indirect effect Height datum

Observation on Height Changes of Chinese Tide Gauges by GPS

在线全文

学校读者我要写书评

暂无评论

Geo-Spatial Information Science 2006年第4期9卷 244-249页

作者： LIU Genyou ZHU Yaozhong XU Houze ZHANG Weimin Institute of Geodesy and Geophysics Chinese Academy of Sciences 340 Xudong Street Wuhan 430077 China. 不详

The height changes of tide gauges directly influence sea level observation. For research of sea level variation in large region or globe, the land vertical displacement must be considered. Two sessions of GPS and absolute gravity observations in 2001 and 2003 are used to determine the horizontal and vertical motion of China coast in ITRF2000 and Eurasia frame. The difference between results of continuous observation and periodic observation is discussed.

关键词： GPS absolute gravity crust deformation height changes sea level variation tide gauge CLC NUMBER P228.42

gravity changes before and after the 2010 Ms7.1 Yushu earthquake

在线全文

学校读者我要写书评

暂无评论

Geodesy and Geodynamics 2012年第4期3卷 1-6页

作者： Zhu Yiqing Liu fang Cao Jianping Zhao Yunfeng State Key Laboratory of Geodesy and Earth's Dynamics Institute of Geodesy and GeophysicsChinese Academy of Sciences Second Crust Monitoring and Application Center China Earthquake Administration Earthquake Administration of Shanxi Province

absolute and relative gravity observations from 1998 -2010 from the China Crustal Movement Ob- servation Network, a major national scientific project, have been used to model the gravity field and its varia- tions associated with the April 14, 2010 Ms7.1 Yushu earthquake. The evolution of the regional gravity field and its relationship with seismicity before and after the Yushu earthquake are studied. The observed gravity changes are closely related to the active Ganzi-Yushu Fault, and gravity measurements can be used to observe the migration of material accompanying active faults and crustal tectonics. The dynamic variation of the gravity field reflects its evolution prior to and during the Yushu earthquake. The gravity measurements near its epicen- ter are as large as 80 × 10-s m/*** they show wave-like increases with time prior to the Yushu earth- quake.

关键词： absolute gravity relative gravity Yushu earthquake tectonic deformation