Imaging the Earth with Multiple Scattering Speckle

这个项目的重点是利用波的多次散射，在实验室和野外对地球材料做出新的推断(统计和确定)。该项目是物理声学实验室和CSM超快光学实验室之间的合作，代表着超快光学在地球物理中的首次应用。激光技术(特别是锁模飞秒激光器)的新进展意味着我们可以显著加快波形数据的采集速度；以至于可以实时进行“3D地震测量”(即粒子运动时间序列的密集空间测量)。该项目涉及的实验包括超声波在岩石中的传播、井筒中的声学测量和野外条件下的地面测量。这些测量的关键应用包括实时空间裂缝可视化，明确区分散射衰减和本征衰减的能力，以及从多个散射斑中恢复随机介质的有效格林函数。

This project focuses on the exploitation of multiple scattering of waves to make new inferences (statistical and deterministic) about earth materials, both in the laboratory and in the field. The project is a collaboration between the Physical Acoustics Laboratory and the Ultrafast Optics Laboratory at CSM and represents the first application of ultrafast optics to geophysics. New advances in laser technology (specifically mode-locked femtosecond lasers) mean that we can dramatically speed up our waveform data acquisition; so much so that "3D seismic surveys" (i.e., dense spatial measurement of particle motion time series) can potentially be done in real-time. The experiments involved in this project include both ultrasonic wave propagation in rocks, acoustic measurements in boreholes and surface measurements in field conditions. Key applications of these measurements include spatial fracture visualization in real-time, theability to unambiguously separate scattering attenuation from intrinsic attenuation as well as the retrieval of the effective Green's function of a random medium from multiple scattering speckle.