The shallow elastic structure of the lunar crust: New insights from seismic wavefield gradient analysis

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• 作者：David Sollberger ; Cedric Schmelzbach ; Johan O. A. Robertsson ; Stewart A. Greenhalgh ; Yosio Nakamura ; Amir Khan
• 刊名：Geophysical Research Letters
• 出版年：2016
• 出版时间：16 October 2016
• 年：2016
• 卷：43
• 期：19
• 页码：10,078-10,087
• 全文大小：1.0MB
• ISSN：1944-8007

文摘

Enigmatic lunar seismograms recorded during the Apollo 17 mission in 1972 have so far precluded the identification of shear-wave arrivals and hence the construction of a comprehensive elastic model of the shallow lunar subsurface. Here, for the first time, we extract shear-wave information from the Apollo active seismic data using a novel waveform analysis technique based on spatial seismic wavefield gradients. The star-like recording geometry of the active seismic experiment lends itself surprisingly well to compute spatial wavefield gradients and rotational ground motion as a function of time. These observables, which are new to seismic exploration in general, allowed us to identify shear waves in the complex lunar seismograms, and to derive a new model of seismic compressional and shear-wave velocities in the shallow lunar crust, critical to understand its lithology and constitution, and its impact on other geophysical investigations of the Moon's deep interior.