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181.
G. Clitheroe O. Gudmundsson B. L. N. Kennett 《Australian Journal of Earth Sciences》2013,60(2):209-216
The initial coda of teleseismic P‐waves contains considerable information about the crust and upper mantle structure directly beneath a receiver. When this information can be recovered for a dense network of seismographs much can be learned about the structure of the earth. Data from the high quality broadband seismic stations of the SKIPPY and KIMBA projects along with permanent stations are used to investigate the upper crustal structure of Australia. A dataset of 65 shear‐velocity models derived from receiver functions has enabled the sedimentary and upper crustal structure of Australia to be summarised. Regions of thick soft sediment show good agreement with topographical lows. A simple relation between upper‐crustal velocity and magnetisation, as has been suggested by other investigators, has not been observed, but this may be due to the magnetic signal being muted by overlying sediments. A prominent mid‐crustal discontinuity is apparent in the Tasman and New England mega‐elements. This may represent a mid‐crustal décollement that had structural control during accretion. 相似文献
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Preliminary analysis of teleseismic receiver functions of the Ningxia and its adjacent area 下载免费PDF全文
The teleseismic receiver functions of digital seismic network of Ningxia and its adjacent area are calculated with two different Gauss filter factors. The accuracy and stability of the receiver functions are discussed. The h-k stacking method is applied to estimate the crustal thickness and velocity ratio beneath seismic stations. The results indicate that there are sharp changes of crustal thickness and velocity ratio in the studied region. This region is located in the northeastern margin of Tibet, and also a junction of several first-grade blocks. The large contrast of crustal structure in this region is considered to be resulted from the interaction of these blocks. Our results are helpful to construct the completed model of the formation and evolution of the Tibet. Some local structures are also discussed combining with the geological faults. 相似文献
184.
??????GNSS??????????????????????????α??????INS????GNSS??????????????????????????????????α??????????????????????????INS?????α??α????????????GNSS?????????????????????й?????????????????????????????????????GNSS??????????????????????????????????????????α????????????????????? 相似文献
185.
???????????????????λ??????????????λ???????????????????????????????????仯??????????òο?????????????????ο?????費???·?????????????????????????λ???????????????????????????????????????????????????????????λ????? 相似文献
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利用中国地震局地质研究所地震动力学国家重点实验室在川西地区布设的大规模密集流动宽频带地震台阵记录的远震P波波形数据,分别采用波形互相关和加权叠加方法研究了地壳各向异性。作为初步结果,得到了龙门山断裂两侧4个宽频带流动台站的接收函数莫霍面Ps转换震相快波方向和分裂时间延迟。结果表明:1)波形互相关方法总体上优于方位加权叠加方法,它不但可以给出快波方位,而且可以给出快慢波的时间延迟;方位加权叠加方法测量结果存在不确定性,其原因在于难以确定介质各向异性对称轴的方位;同时采用上述2种不同方法研究地壳各向异性参数有助于判断测量结果的可靠性;2)四川盆地内快波偏振方位基本一致,表明四川盆地地壳整体性较好,横向非均匀变形较弱;3)以汶川地震主震的震中区为界,松潘-甘孜地块北侧快波偏振方位与龙门山断裂近于平行,表明在四川盆地坚硬地壳的阻挡作用下,龙门山断裂附近松潘-甘孜地块北侧可能存在中下地壳软弱物质沿断层向NE方向的扩张变形,而其南侧处于正向挤压的状态。该结果有助于解释汶川MS8.0地震的单侧破裂过程及其余震发育的特征 相似文献
188.
收集整理2007年以来延边地震台记录的113个远震数字波形资料,采用远震接收函数反演延边地震台下方地壳结构,运用H-Kappa叠加方法,计算得到台站下方地壳厚度和泊松比.采用全球平均地壳模型作为初始模型,反演台站下方0-100 km的S波速结构.反演结果表明,延边地震台下方地壳厚度为30.8 km,波速比为1.84,泊松比较高,为0.29.在台站下方15-20 km及25-30 km处存在低速层. 相似文献
189.
We use 15 seismic stations,crossing the Qinling orogen(QO),Weihe graben(WG)and Ordos block(OB),to study the crustal structures by receiver functions(RFs)methods.The results show quite a difference in crustal structures and materials of three tectonic units(orogenic belt,extentional basin and stable craton).The average crustal thickness in the northern QO is 37.8 km,and Poisson ratio is 0.247,which indicates the increase of felsic materials in QO.In the southern OB,the average crustal thickness is 39.2 km and Poisson ratio is 0.265.Comparatively high value of Poisson ratio is related with old crystallized base in the lower crust and shallow sediments.The artificial RFs reveal that low-velocity and thick sediments have a significant effect on phases of the Mohorovi i discontinuity(Moho).As a result,the Moho phases in WG are tangled.S-wave velocity(VS)inversion shows that there are shallow sediment layers with 4–8 km’s thickness and high velocity zones in the middle-lower crust in WG.Complex Moho structure and high velocity zone may have been induced by the activities of the Weihe faults series. 相似文献
190.