共查询到18条相似文献,搜索用时 171 毫秒
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从大量重力测量资料研究中,发现温度变化对重力测量精度的影响很大,尤其在面积较大的范围中进行重力测量,环境温度差异大,温度对重力仪的影响更为复杂。在目前高精度重力仪数量尚不能满足需要的情况下,提高石英弹簧重力仪的测量精度是十分必要的。为此,我们在1982年与有关厂家协作,制成了一台半导体制冷、制热重力仪温度测试装置,用以模拟野外工作环境温度变化。从1983年7月至1984年4月我们用该装置对列入国家地震局“清理攻关项目”的六台CG-2型,一台ZSM型和十六台Worden型石英弹簧重力仪进行了系统的温度测试。参加测试的仪器型号见下表 相似文献
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用维尼迪科夫(Vinedikov)调和分析方法,计算2008年1月1日至2010年12月31日兰州地震台PET重力仪观测资料,获得几个主要潮波的潮汐参数.对日均值采用最小二乘拟合法,分析非潮汐重力变化信息.基于一元线性回归,分析气压对重力观测的影响,结果表明:气压对重力观测具有一定影响. 相似文献
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引言 唐山地震重力变化资料发表后,受到国内外学者的关注,一些评论认为此资料十分宝贵。但由于在唐山地震前所使用的CG-2型重力仪的观测精度并不很高,也有一些评论对观测资料的可靠程度提出质疑,主要有以下几点: (1)唐山地震前重力变化的量级大于目前世界上所公认的震前重力变化的量级。目前公认的震前重力变化一般小于100微伽,且其变化与高程变化有关。重力变化与高程变化之比在布格梯度——空间梯度范围内波动。(2)石英弹簧重力仪存在气压变化影 相似文献
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对天津蓟县地震台2套相对重力仪2018—2019年观测数据进行潮汐分析和提取非潮汐重力残差处理,研究水文变化所引起的重力响应。结果表明,蓟县地震台2套重力仪精度较高;GS-15重力仪重力残差与水文变化间存在较好的相关性,具体表现为降水时重力减少,降水结束后重力增大,水位下降时重力减少,水位上升时重力增大,但其间都存在延迟对应关系。 相似文献
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通过气压变化对重力观测的影响和大气潮对重力固体潮的负荷效应二方面的研究,得出将GS型重力仪置于密封装置,能使气压的影响降低1个数量级。 相似文献
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对天津蓟县地震台2套相对重力仪2018—2019年观测数据进行潮汐分析和提取非潮汐重力残差处理,研究水文变化所引起的重力响应.结果表明,蓟县地震台2套重力仪精度较高;GS-15重力仪重力残差与水文变化间存在较好的相关性,具体表现为降水时重力减少,降水结束后重力增大,水位下降时重力减少,水位上升时重力增大,但其间都存在延... 相似文献
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本文选取GS-15型、gPhone型、PET型和CG-5型等4种陆地重力观测常用的相对重力仪,对比这几种仪器在不同背景观测环境下和不同测评时长的地震噪声等级计算结果。综合分析结果显示:金属弹簧(gPhone型、GS-15型、PET型)与石英弹簧型(CG-5型)重力仪对环境噪声的敏感性存在一定差异,但取测评时长中最平静5天和最平静1天数据所计算的地震噪声等级结果相近。因此,对于流动重力观测点,可以取最平静1天的数据来评价观测点的环境噪声水平和观测精度,可为流动重力测点选址提供方法支撑。 相似文献
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1978年5月使用了18台精度较高的重力仪在南京和北京分别建立了地震系统的重力检定场.本文结合以上成果和有关重力比较测定的资料, 从分析格值变化的各种因素及其产生的误差入手, 说明仪器格值标定的重要性和具体要求, 提出了选建地震系统重力检定场的方法技术和减小格值误差、提高测量精度的可能途径. 相似文献
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基于标准大气定律和大气圆柱体分布模型,本文引进了大气重力格林函数,用离散格积方法求得了大气对重力场观测的影响,对台站高程、周围地形和地表温度变化等因素的影响问题进行了讨论.结果说明台站近区气压变化是大气重力信号的主要贡献者,考虑大气质量负荷引起的弹性地球形变效应后,对距台站0.5°的区域积分获得的大气重力导纳值为-0.3603μGal/hPa,占全球大气变化引起的总信号的90%以上,这一理论模型结果与超导重力仪实测结果相吻合,并能较有效地用于消除重力观测中的气压干扰成分. 相似文献
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During the nineteen-seventies, the geophysical satellites EOS-3 and SEASAT-1 provided very accurate sea-surface heights, which could be employed as information on the marine geoid. Geoid height can easily be converted to gravity anomalies, and since the tracks of GEOS-3 and SEASAT-1 were extremely dense, the gravity anomaly data thus obtained were the densest and of the widest coverage ever obtained for gravity measurements.The authors completed a self-consistent free-air gravity anomaly map in the Antarctic region, covering from 45°S to the South Pole, using all the gravity data available at present: namely, those obtained by satellites and the ground-truth data obtained by land gravimeters and ship borne gravimeters (Segawa et at., 1984).The bouguer anomaly was also calculated, from which estimates of crustal and lithospheric structures were made. This has resulted in clarifying the relationships among sub-bottom structures between the mid-oceanic ridges surrounding the Antarctic plate and the Ross Sea. 相似文献
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Karel Diviš Viktor Höschl Stanislav Hrách Reviewer M. Pick 《Studia Geophysica et Geodaetica》1981,25(1):14-23
Summary The results of pressure tests of gravimeters Worden No. 961, CG-2 Nos 174 G, 323 and 374 in a pressure chamber are presented. Apart from deriving the barometric correction, the authors have also studied accompanying phenomena, which occur during pressure tests of gravimeters — the barometric after-effect and hysteresis. The processing of the results in two ways differing in the method of eliminating the drift of the gravimeter, yields nearly identical results. The hysteresis was investigated for atmospheric pressures of 720±150 Torr (1 Torr=0.133322 kPa), a rate of change of 30 Torr/min and a temperature of 22°C. The barometric after-effect was investigated in greater detail for the CG-2 gravimeter No. 174 G at a pressure difference of 225 Torr, rate of change of 30, 15 and 7.5 Torr/min and a gravimeter heating temperature of 35 °C. It was also found that the barometric correction can be determined, using the method given, with sufficient accuracy. As a result of the existence of hysteresis, however, the derived results must be applied carefully in field gravity measurements with some gravimeters. 相似文献
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F. Greco G. Currenti G. D’Agostino A. Germak R. Napoli A. Pistorio C. Del Negro 《Bulletin of Volcanology》2012,74(7):1745-1756
To achieve a balance between uncertainty and efficiency in gravity measurements, we have investigated the applicability of combined measurements of absolute and relative gravity as a hybrid method for volcano monitoring. Between 2007 and 2009, three hybrid gravity surveys were conducted at Mt Etna volcano, in June 2007, July 2008, and July 2009. Absolute gravity data were collected with two absolute gravimeters, which represent the state of the art in recent advances in ballistic gravimeter technology: (1) the commercial instrument FG5#238 and (2) the prototype instrument IMGC-02. We carried out several field surveys and confirmed that both the absolute gravimeters can still achieve a 10 μGal or better uncertainty even when they are operated in severe environmental conditions. The use of absolute gravimeters in a field survey of the summit area of Mt Etna is unprecedented. The annual changes of the gravity measured over 2007–2008 and 2008–2009 provide unequivocal evidence that during the 2007–2009 period, two main phenomena of subsurface mass redistribution occurred in distinct sectors of the volcano, accompanying different eruptive episodes. From 2007 to 2008, a gravity change of ?60?μGal was concentrated around the North-East Rift. This coincided with a zone affected by strong extensional tectonics, and hence might have been related to the opening of new voids. Between 2008 and 2009, a North-South elongate feature with a maximum gravity change of +80?μGal was identified in the summit craters area. This is interpreted to indicate recharge of a deep-intermediate magma storage zone, which could have occurred when the 2008–2009 eruption was still ongoing. 相似文献