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1.
Jun Yang 《地震学报(英文版)》1998,11(4):455-465
The relation of tidal factor value to tiltmeter type has been founded from the harmonic analysis for observational data. The
relation is deducted theoretically. It is discovered that the frequency responses of different type tiltmeters and operative
periods or damping constant are slightly different in same station. The tiltmeter of small operative period is able to receive
more precursory information. That is the tidal factors obtained from harmonic analysis for observed data on tiltmeter of different
damping constant are different. The relation between frequency response and tidal factor is searched. It is necessary to calibrate
absolutely tiltmeter to predict earthquake. In order to obtain any amount of ground tilt information, it is necessary to select
appropriately different frequency tiltmeters to make comprehensive observation.
The study is sponsored by the Chinese Joint Seismological Science Foundation, No. 91100. 相似文献
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Kiyoo Mogi 《Pure and Applied Geophysics》1984,122(6):765-780
The temporal variation in precursory ground tilt prior to the 1944 Tonankai (Japan) earthquake, which is a great thrust-type earthquake along the Nankai Trough, is discussed using the analysis of data from repeated surveys along short-distance leveling routes.Sato (1970) pointed out that an anomalous tilt occurred one day before the earthquake at Kakegawa near the northern end of the focal region of the earthquake. From the analysis of additional leveling data, Sato's result is re-examined and the temporal change in the ground tilt is deduced for the period of about ten days beginning six days before the earthquake. A remarkable precursory tilt started two or three days before the earthquake. The direction of the precursory tilt was up towards the south (uplift on the southern Nankai Trough side), but the coseismic tilt was up towards the southeast, perpendicular to the strike of the main thrust fault of the Tonankai earthquake. The postseismic tilt was probably opposite of the coseismic tilt. The preseismic tilt is attributed to precursory slip on part of the main fault. If similar precursory deformation occurs before a future earthquake expected to occur in the adjacent Tokai region, the deformation may help predict the time of the Tokai earthquake. 相似文献
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尝试利用多台定点地倾斜形变资料构建形变场时空动态演化图形的方法,对中国大陆47个定点形变台水管倾斜仪资料进行分析处理,构建了地倾斜形变场时空演化分布图像.以2001年11月14日昆仑山口西8.1级地震为例,研究了地震前后水管倾斜资料的时空演化特征.结果显示在地震前后较多台站水管倾斜仪的日均值都出现了趋势上的较大变化,东西向日均值、南北向日均值和南北向潮汐因子的空间分布也都出现了大范围的变化,而东西向M2波的潮汐因子没有出现较明显的变化.随着定点形变台站的建设和资料的积累,该方法可以构建每月或者每周形变场的变化,有望用于地震预报工作. 相似文献
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Antonio Eff-Darwich Olivier Grassin José Fernández 《Pure and Applied Geophysics》2008,165(6):1049-1070
Continuous monitoring of ground deformation in the volcanic island of Tenerife, Canary Islands, is based on GPS networks,
since there are as yet no tiltmeter stations installed on the island. However, there is a world-class astronomical observatory
on the island, the El Teide Observatory, where four tiltmeters, two aligned in the North-South and the other two in the East-West,
are monitoring the movements of the solar telescope THEMIS. THEMIS (Heliographic Telescope for the Study of Solar Magnetism
and Instabilites) is among the three largest solar telescopes in the world. Since THEMIS is located a few kilometers from
the main volcanic structures of the island, in particular the El Teide-Pico Viejo stratovolcano, and the precision of the
inclinometers is comparable to those used in geophysical studies, we carried out the analysis of the tilt measurements for
the period 1997–2006. The tiltmeters at THEMIS are placed in the seventh floor of a tower, hence their sensitivity to geological
processes is reduced compared to geophysical installations. However, THEMIS measurements are the only terrestrial data available
in Tenerife for such a long period of observations, which include the sustained increase in seismic activity that started
in 2001. In this sense, a significant change was found in the East-West tilt of approximately 35 μ-radians between the years
2000 and 2002. Some theoretical models were calculated and it was concluded that such tilt variation could not be due to dike
intrusions, nor a volcanic reactivation below the El Teide-Pico Viejo volcano. The most likely explanation comes from dislocations
produced by a secondary fault associated to a major submarine fault off the eastern coast of Tenerife. In any case, taking
into account the nearly permanent data recording at THEMIS, they could be considered as a complement for any ground deformation
monitoring system in the island. 相似文献
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Strain and tilt changes measured during a water injection experiment at the Nojima Fault zone, Japan 总被引：2，自引：0，他引：2
Kunio Fujimori Hiroshi Ishii Atsushi Mukai Shigeru Nakao Shigeo Matsumoto Yasuhiro Hirata 《Island Arc》2001,10(3-4):228-234
Abstract In order to make geophysical and geological investigations of the Nojima Fault on Awaji Island, Japan, three boreholes measuring 1800 m, 800 m and 500 m deep were drilled into the fault zone. The fault is one of the seismic source faults of the 1995 Hyogo-ken Nanbu earthquake of M 7.2. A new multicomponent borehole instrument was installed at the bottom of the 800 m borehole and continuous observations of crustal strain and tilt have been made using this instrument since May 1996. A high-pressure water injection experiment within the 1800 m borehole was done in February and March 1997 to study the geophysical response, behavior, permeability, and other aspects of the fault zone. The injection site was located approximately 140 m horizontally and 800 m vertically from the instrument. Associated with the water injection, contraction of approximately 0.7 × 10−7 str (almost parallel to the fault) and tilt of approximately 1 × 10-7 rad in the sense of upheaval toward the injection site were observed. In addition to these controlled experiments, the strainmeter and tiltmeter also recorded daily variations. We interpret strain and tilt changes to be related to groundwater discharge and increased ultra-micro seismicity induced by the injected water. 相似文献
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倾斜观测已在地球物理领域以及地震部门获得广泛应用。有时,由于种种原因井下倾斜仪难以定向,这会对倾斜观测资料的解释带来困难,本文阐明一种利用潮汐信号进行井下倾斜仪定向反演的方法。 相似文献
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在整理垂直摆地震响应的基础上,采用USGS提供的有限断层模型和速度结构模型,运用德国地学研究中心（GFZ）王荣江研究员开发的（PSGRN/PSCMP）计算程序,分析日本MW 9.0地震和中俄交界MS 6.6地震倾斜场变化,并与垂直摆记录数据进行对比。通过整理现有地质资料和断层数据,模拟依舒断裂带北段鹤岗周边发生MS 6.0地震时,该地区同震及震后倾斜场的变化,以了解不同震源性质的地震产生的地倾斜变化及对鹤岗地区产生的影响。 相似文献
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采用形态法和小波分析法,分析2020年3月20日蒙古MS 5.9地震震中距400 km范围内巴里坤、富蕴和芨芨台地震台倾斜观测资料的震前异常特征。结果表明：3套资料在震前均具有明显的中短期异常,分别表现为反向趋势变化、破年变形态和倾斜速率减缓的特征;使用db4小波对3套资料进行分析,其6—9阶在震前出现周期为几天至几十天的低频短期异常,同时巴里坤水平摆倾斜仪EW分量8—9阶趋势异常较显著。 相似文献
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临汾地震台摆式倾斜仪的监测能力 总被引：1，自引：0，他引：1
我国境内几次中强震及山西地区6次有感地震前,临汾地震台两种摆式倾斜仪存在有不同反映,探讨不同摆式倾斜仪对同一地震监测能力的差异性和同一仪器对不同地震的异常反映能力,结果表明：①摆式倾斜仪监测震兆信息的距离范围由仪器自身的监测能力（综合噪声水平及观测精度）和未来震级的大小所决定;②对于不同地震,两摆式倾斜仪所表现出的异常形态不同,即便在同一观测仪器上表现出来的异常形态也存在差异;同一地震两摆式倾斜仪所反映的异常并非呈相关一致性,而且同一仪器的不同方向对异常信息的捕捉能力也存在明显差异。 相似文献
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-- Daily averaged tilt component data from four sites of the Central Apennines (Italy) revealed intermediate-term tilts of a few months as possible precursors of the seismic sequence occurred in the Umbria-Marche region during 1997. A change was also observed in the secular tectonic trend recorded at one site and referred to the same seismic sequence. The observed intermediate-term preseismic tilts are considered as the manifestation of aseismic creep episodes in the fault materials close to the tilt sites. The mechanism refers to a strain field slowly propagating from the dilatancy (focal) area to the tiltmeters, through rigid crustal blocks separated by weak transition zones with viscoelastic rheology. This propagation is thought to be the cause of the local aseismic fault slip recorded by tiltmeters. In one case such creep strains revealed to have larger amplitude and higher frequency content than those accepted for fault materials, and this was attributed to an amplified response of the heterogeneous ground surface at the site. The existence of a propagating strain field is confirmed by the different onset time delays in the preseismic tilt signals recorded at different distances from the same earthquake. In particular, the onset time delays observed at each tilt site appear to increase with increasing distance of such site from the epicentral area. At greatest distances, where the preseismic strain becomes negligible, the characteristic intermediate-term ground tilts vanish completely. 相似文献
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对华清温泉在水化观测中的干扰因素及特征，进行了分析探讨。通过对观测资料、水文地质结构的分析，指出降水、排污、供水开采等因素，对泉点没有影响。得出只有本身不抽水时，井内形成的“滞留水”，对观测结果影响较大及Ｈｅ、Ｒｎ含量明显降低，Ｏ２含量增高，Ｎ２变化不大，ＣＯ２含量亦降低的结论。指出供电不足是形成滞留水的主要原因。 相似文献
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Abstract Indications of transient crustal displacement associated with the 3 March 1985, M, = 7.8, Central Chile earthquake are evidenced by various observational devices. Almost half a meter of coastal uplift at localities close to the epicentral region was detected by repeated leveling lines. A tide gauge at Valparaiso revealed minor coseismic coastal subsidence (∼ 10 cm) continuously developing after the earthquake. Two limnigraphs, 27 km apart, that were situated at the extremes of Rapel Lake to the south of the leveling line, have recorded continuously the equipotential lake level for more than 10 years, providing a permanent very-long-base tiltmeter. The water level difference at the two limnigraphs as a function of time resembles a ramp function, beginning approximately at the time of the earthquake occurrence and gradually developing over a period of 10 months with a maximum amplitude of 120 mm or 4.4 p radians in tilt. The shape of the time-dependent tilt is mimicked by the sea level signal recorded at Valparaiso, ∼ 100 km away from Rapel Lake, showing a maximum coastal subsidence of 0.6 m. Comparisons of sea level changes produced by the 1971, M, = 7.5, earthquake indicates that they represent rupture in different portions along the seismogenetic region as well as a different rupture mode. Gravity surveys carried out in three different pre- and post-seismic epochs, along the segment of the leveling line which shows major coseismic uplift, indicate that the whole region has subsided, post-seismically, 10 em in 5 years. These observations are interpreted in terms of a variable slip dislocation model. Inversions show that it is the more than 2 m of fault displacement in 10 months of post-seismic movement along the contact between the Nazca and South America plates, which is interpreted to be responsible for the time-dependent elevation changes. 相似文献
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汶川地震前南北地震带中北段地形变变化特征的研究 总被引：4，自引：0，他引：4
2008年5月12日汶川8.0级地震是我国自建国以来灾难最为严重的一次强地震。 文中讨论了汶川地震前震源附近与外围地区潮汐形变变化及龙门山地震带、 鲜水河地震带和祁连山地震带断层活动的特点。 分析结果表明: 震前沿龙门山地震带分布的雅安、 汶川及茂县观测台地倾斜测项在2006年初发生转折, 由单向东倾或西倾转向平稳, 临震前无明显变化; 龙门山断裂带及附近地区有5个断层水准观测场地, 除耿达场地观测到巨幅变化外, 其他场地震前未观测到突出的前兆性变化。 震源外围龙灯坝断层蠕变仪(Δ=220 km)震前观测到持续时间在3个月左右的突变性异常, 但依据突变持续时间较难估计相应地震为8级。 而离震中较远的祁连山地震带中西段, 震前也有巨大的断层水准变化, 其与汶川地震的关系值得讨论。 相似文献