Probing the Lunar Interior using Lunar-A mission data

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The purpose of this study was to probe the Lunarinternal structure using data of Lunar-A mission whichis promoted by Institute of Space and Astronautical Science, Japan. However, the mission will be delayed until 2003 because of some troubles in development of devices. So we could not achieve the initial purpose, and, instead, we prepared some software tools and database to be able to analyze quickly Lunar-A data when the data are available. The following are the results(1) Lunar seismic modelWe calculated seismic profile of the Lunar interior on basis of the petrologically accessible scenario of the Lunar forming by Okuchi and Takahashi (1994). The resultant Profile is consistent with the result from apollo seismic data. The model will be used as a reference model on analysis of Lunar-A data.(2) database of apollo lunar seismic recordsWe made a database of apollo lunar seismic records. The seismometers of the Lunar-A mission are 10 times more sensitive than those of the Apollo project. However, The number of the Lunar-A seismometer is only two. So the aid of the data sets of the apollo project will be important to the Lunar-A mission. The database are accessible via http : //www.geo.titech.ac.jp/lunarA/.(3) reproduction of scattering wave profileLunar seismic wave profiles are know to have long duration of scattered waves. We could retrieve the feature using a simple stratified structure in the very shallow part of the crust. On analysis of Lunar-A data, we must take it into consideration.(4) determination of the Lunar core sizeBy synthetic calculation of seismic waves induced by deep moon quakes, we found an effective method to clear the Lunar core size. The interval time between pP and Pdiff/PKP is detectable in spite of contamination of long scattering waves. The time is sensitive to the Lunar core size. Note the synthetic calculations are very heavy. So we improve the calculation method (the DSM method) to be more efficient.