Lithospheric structure of the Arabian and Eurasian collision zone in eastern Turkey from S-wave receiver functions

Crustal and upper-mantle seismic discontinuities beneath eastern Turkey are imaged using teleseismic S -to- P converted phases. Three crustal phases are observed: the Moho with depth ranging between 30 and 55 km, indicating variable tectonic regimes within this continental collision zone; an upper-crustal discontinuity at approximately 10 km depth; and various crustal low-velocity zones, possibly associated with recent Quaternary volcanism. Imaging of the upper mantle is complicated by the 3-D geometry of the region, in particular due to the Bitlis–Zagros suture zone. However, several upper-mantle S -to- P converted phase are identified as being the signature of the lithosphere–asthenosphere boundary (LAB). The inferred LAB for the Eastern Anatolian Accretionary Complex indicates that eastern Turkey has an anomalously thin (between ∼60 and 80 km) lithosphere which is consistent with an oceanic slab detachment model. The observed LAB phases for the Arabian shield and Iranian plateau indicate that lithospheric thickness for these stable regions is on the order of 100 to 125 km thick, which is typical of continental margins.     

Lithospheric thickness beneath the Dabie Shan, central eastern China from S receiver functions

P and S receiver functions obtained from a portable array of 34 broad-band stations in east central China provide a detailed image of the crust–mantle and lithosphere–asthenosphere boundaries (LAB) in the Dabie Shan and its adjacent areas. Clear S -to- P converted waves produced at the LAB show a thin lithosphere beneath the whole study area. Based on our results, the thickest lithosphere of 72 km is observed beneath the southern part of the area within the Yangtze craton, whereas beneath the North-China platform, the lithosphere is only 60 km thick. S receiver functions also reveal, in good agreement with P receiver functions, a maximum depth of the Moho beneath the Dabie Shan orogen at approximately 40 km. Furthermore, we interpret the structural difference at 32° latitude as the probable location of the mantle suture formed between the Yangtze and the Sino-Korean cratons.     

GNSS软件无线电接收机及典型案例

介绍了GNSS软件无线电接收机和它与传统接收机相比的优缺点，并引述了典型的GNSS软件接收机及其应用。     

Determination of Precise Instantaneous Height at Multibeam Transducer

To overcome the shortcomings of the traditional multibeam survey and data processing, a new method is presented for the precise determination of the instantaneous height at the multibeam transducer by ...     

浅水多波束勘测数据精细处理方法

系统分析多波束勘测水深的误差表现,针对性地提出相应的改正措施,首先去掉勘测质量差的重复覆盖条带,改正横摇校准残差,然后根据提出的浅水常梯度声速模型,搜索确定模型参数,以此模型参数及波束到达角和旅行时对每个波束重新进行归位计算,接着自动删除多余边缘波束,最后网格化水深数据并以对应的波束号确定中央和边缘波束位置,对格网中边缘波束进行强制微调,得到光滑的格网水深数据。从实测数据结果来看,本文算法物理意义明确、切实可行、后处理速度较快,改正结果较理想。     

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夏威夷瓦胡岛地区接收函数特征分析

研究壳幔间断面转换波信息的接收函数方法是一种非常有效的地球物理探测技术。我们采用P波接收函数方法对夏威夷瓦胡岛地区布设的一个宽频带地震台站所采集到的数据进行了处理,得到该台站下方接收函数径向分量和切向分量的特征,并对所得到的径向接收函数进行时深转换处理,得到该地区410 km间断面的深度信息。结果表明:该台站的西北方和西南方存在明显的横向非均匀介质,且该地区410 km间断面的深度变浅,大约为390 km,反映了瓦胡岛下方存在热的地幔熔融物质。     

多波束测深误差源对测点位置归算影响研究

针对Rob Hare提出的多波束测点位置归算精度估计模型的不足,建立了顾及各项改正数之间相关性的改进模型.在多波束测点位置归算模型的基础上,分析了影响测点位置归算的各项误差来源,推导了各误差源对测点位置归算精度估计的影响量,结合算例,分别利用两种模型计算了各误差源对测点位置归算精度的影响量级,绘制了各误差源的误差曲线图与总位置误差曲线图,通过对计算结果的分析比较,得出了两种模型在评估多波束测点位置归算精度时存在的差异,由于顾及到改正数间的相关性,认为改进模型更加科学合理.     

卫星导航接收机基于IIR陷波器的单频干扰抑制性能分析

单频干扰对卫星导航系统的破坏性很强,仅靠系统自身的抗干扰能力很难保证系统正常工作。因此,有必要引入干扰抑制技术。在现有的众多抑制单频干扰的信号处理手段中,时域陷波抑制技术因其实现简单、抗干扰性能好等优点而被广泛使用。针对单频干扰对卫星导航接收机的影响,分析了IIR陷波器的陷波原理,比较了直接型和格型两种陷波器的性能,研究了陷波器参数与零陷深度、陷波带宽的关系,并基于二阶陷波器扩展分析了高阶陷波器的抑制性能。通过仿真实验,验证了上述结论的正确性。