Elastic properties of lunar regolith from vertical seismic profiling

T. Tsuji, T. Kobayashi, S. Aoki, H. Kanamori, T. Aizawa, T. Matsuoka

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    3 Citations (Scopus)

    Abstract

    To reveal shallow subsurface structures as well as velocity distribution of the lunar regolith layer, we propose a survey of Reverse Vertical Seismic Profiling (RVSP) under a program of SELENE-2. In the RVSP experiment, seismic sources generated within the borehole are recorded by receivers deployed on the Moon surface. In Lunar Soil Mechanics (LSM) Investigation System, drilling operations and shear strength measurements (1 m in total depth) are planned for the regolith layer. We attach a vibrator at the shear experiment devices and generate an active source signal within the borehole. MEMS sensors are further attached at legs of the lander and record the wavefields derived from the vibrator within the borehole. Here we show the effectiveness of RVSP survey using the proposed simple (small-size) acquisition system from simulation study and laboratory experiments. First, we conducted simulation study for the designed survey geometry in order to determine the survey parameters (e.g., source signal). This simulation study demonstrates that the source signal should contain high-frequency components in order to resolve shallow velocity structure from short offset data (less than 3m). Since the high-frequency signal is much attenuated, we used a sweep waveform for the source signal. To examine the ability of the sweep waveform for the high-attenuation regolith layer, we conducted small-scale RVSP experiments in laboratory using lunar soil simulant. The laboratory experiments demonstrated that the seismic signal can be retrieved by cross-correlation between source (sweep) waveform and recorded waveform. From the direct P-waves and reflected waveforms observed on the processed gathers, P-wave velocity of the regolith was estimated as ∼85m/s. This study shows that the proposed simple RVSP survey could reveal the shallow subsurface structures as well as velocity within the regolith layer.

    Original languageEnglish
    Title of host publicationEarth and Space 2012 - Proceedings of the 13th ASCE Aerospace Division Conference and the 5th NASA/ASCE Workshop on Granular Materials in Space Exploration
    PublisherAmerican Society of Civil Engineers (ASCE)
    Pages84-93
    Number of pages10
    ISBN (Print)9780784412190
    DOIs
    Publication statusPublished - 2012
    Event13th Biennial ASCE Aerospace Division International Conference on Engineering, Science, Construction, and Operations in Challenging Environments, Earth and Space 2012 and the 5th NASA/ASCE Workshop on Granular Materials in Space Exploration - Pasadena, CA, United States
    Duration: Apr 15 2012Apr 18 2012

    Publication series

    NameEarth and Space 2012 - Proceedings of the 13th ASCE Aerospace Division Conference and the 5th NASA/ASCE Workshop on Granular Materials in Space Exploration

    Other

    Other13th Biennial ASCE Aerospace Division International Conference on Engineering, Science, Construction, and Operations in Challenging Environments, Earth and Space 2012 and the 5th NASA/ASCE Workshop on Granular Materials in Space Exploration
    Country/TerritoryUnited States
    CityPasadena, CA
    Period4/15/124/18/12

    All Science Journal Classification (ASJC) codes

    • Civil and Structural Engineering
    • Environmental Engineering
    • Building and Construction

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