用波形梯度法研究介质速度，各向异性和衰减特性

波形梯度法是Charles A. Langston教授引进到地球物理领域的一种全新的台网数据处理方法。本课题负责人将其应用到美国流动台网USARRAY并解决了实际应用中的很多具体问题。该方法有效地利用台网地震波形的时间和空间特性，从单一地震的台网数据可以求得四大波传播参数：传播速度，传播的方向性，几何扩散和辐射模式。从这些波传播参数中计算传播介质的物理特性仍然是个需要解决的问题，而这正是本课题的研究重点。本课题的主要目标是（1）用波形梯度法研究介质的3D速度结构；（2）用波形梯度法研究介质的各向异性。该方法一个最有前景的应用就是用于探测台网覆盖区域的断裂面分布；（3）用波形梯度法研究介质的衰减特性。本课题也将探讨不同震相对该方法的适用性。

Wave Gradiometry is a new array data processing technology that has been introduced to the Geophysics community by Dr. Charles A. Langston. The PI of this project has successfully applied this method to the USArray in the western US region and also solved many practical problems in the real data application. This technology makes use of the spatial and temporal attributes of array waveforms to derive four major wave propagation properties: wave speed, wave directionality, geometrical spreading and radiation pattern. However, the method to obtain the physical properties of media from these wave propagation properties is yet to be developed, and they are the key issues to be solved in this project。The major scientific targets of this project include: (1) obtaining 3D media velocity structure from wavegradiometry; (2) studying the anisotropic property using wave Gradiometry. One of the most promising benefits of this technology is to map the fault distribution in the array-covered region; (3) studying the attenuation using wave Gradiometry. We will also investigate the application of this method to different seismic phases.