The quadratic Wasserstein metric for earthquake location

JOURNAL OF COMPUTATIONAL PHYSICS

卷:373

Article

Chen, Jing¹  Chen, Yifan¹  Wu, Hao¹  Yang, Dinghui¹ 

[1] Tsinghua Univ, Dept Math Sci, Beijing 100084, Peoples R China

关键词: Optimal transport;    Wasserstein metric;    Inverse theory;    Waveform inversion;    Earthquake location;   

DOI  :  10.1016/j.jcp.2018.06.066

来源: Elsevier

【 摘 要 】

In Engquist et al. (2016) [8], the Wasserstein metric was successfully introduced to the full waveform inversion. We apply this method to the earthquake location problem. For this problem, the seismic stations are far from each other. Thus, the trace by trace comparison (Yang et al. [47]) is a natural way to compare the earthquake signals. Under this framework, we have derived a concise analytic expression of the Frechet gradient of the Wasserstein metric, which leads to a simple and efficient implementation of the adjoint method. We square and normalize the earthquake signals for comparison so that the convexity of the misfit function with respect to earthquake hypocenter and origin time can be realized and observed numerically. To reduce the impact of noise, which does not offset each other after the signals are squared, a new control parameter is introduced. Finally, the LMF (Levenberg-Marquardt-Fletcher) method is applied to solve the resulted optimization problem. According to the numerical experiments, only a few iterations are required to converge to the real earthquake hypocenter and origin time. Even for data with noise, we can obtain reasonable and convergent numerical results. (C) 2018 Elsevier Inc. All rights reserved.

【 授权许可】

Free