Seismic Properties of the Central Indian Shield
Seismic Properties of the Central Indian Shield
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DOI：
10.1785/0119990039
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发表时间：
2000-10
影响因子：
3
通讯作者：
Limei Zhou;Wang-Ping Chen;Serdar Özalaybey
中科院分区：
文献类型：
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作者：
Limei Zhou;Wang-Ping Chen;Serdar Özalaybey
我们使用宽带地震数据在海得拉巴调查平均地壳特性的印度中部地盾。基于高质量和方位角覆盖数据的地壳接收器功能（P到SV转换）基本上没有横向分量信号，表明该站附近的横向均匀结构。联合分析的接收功能和基本模式瑞利波的频散的结果在一个简单的模型中的剪切波速度（Vs）与一个中等的梯度为0.010-0.028公里/秒/公里的地壳。莫霍面是尖锐的，在0-4 km的小厚度上，V s的对比度约为0.7 km/s。从莫霍面中部测量，地壳厚度为30-34 km，平均Vs为3.58 ± 0.10km/s。通过模拟Sp和SsPmp相位的时间和波形（SV到P转换），我们估计地壳的平均泊松比为0.26 ± 0.01。这一数值与坦桑尼亚克拉通中发现的太古代克拉通的数值相当，两者都略低于包括元古代和太古代地壳的盾状区域的全球平均值0.29 ± 0.02。低泊松比和缓慢的V的地壳中表明，平均而言，太古宙地壳下的印度盾中部是中间长英质的组成，比全球平均的前寒武纪地壳镁铁质少。
We use broadband seismic data at Hyderabad to investigate average crustal properties of the central Indian shield. Crustal receiver-functions ( P to SV conversions) based on data of excellent quality and azimuthal coverage show essentially no signal on the transverse component, indicating laterally homogeneous structures near this station. A joint analysis of receiver-functions and the dispersion of fundamental mode Rayleigh waves result in a simple model for the shear wave speed ( V s ) with a moderate gradient of 0.010–0.028 km/sec/km in the crust. The Moho is sharp, with a contrast of approximately 0.7 km/sec in V s across a small thickness of only 0–4 km. Measured from the middle of the Moho region, the crust is 30–34 km thick, with an average V s of 3.58 ± 0.10 km/sec. By modeling the timing and waveforms of Sp and SsPmp phases ( SV to P conversions), we estimate the average crustal Poisson9s ratio to be 0.26 ± 0.01. This value is comparable to that found in the Tanzanian craton which is also of Archean age, both values being somewhat lower than the global average of 0.29 ± 0.02 for shield regions that include both Proterozoic and Archean crust. A low Poisson9s ratio and a slow V s in the crust indicate that, on average, Archean crust beneath the central Indian shield is intermediate to felsic in composition, somewhat less mafic than globally averaged Precambrian crust.