1993 Fiscal Year Final Research Report Summary
Reevaluation of lunar internal structure with reanalysis of deep moonquakes
| Project/Area Number |
04835014
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
惑星科学
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| Research Institution | The Institute of Space and Astronautical Science |
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Principal Investigator |
MIZUTANI Hitoshi ISAS Div.Planetary Science, Prof., 惑星研究系, 教授 (00011578)
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| Co-Investigator(Kenkyū-buntansha) |
HAYAKAWA Mashiko ISAI Div.Planetary Science, Assistant, 惑星研究系, 助手 (40228557)
FUJIMURA Akio ISAI Div.Div.Planetary Science, Ass.Prof., 惑星研究系, 助教授 (70173458)
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| Project Period (FY) |
1992 – 1993
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| Keywords | Lunar Seismology / Apollo Project / Lunar Internal Structure / Data Base / Seismic Processing / Planetary Science / Moonquake / Deep moonquake |
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| Research Abstract |
We first analyzed the deep moonquakes from A1 and A33 sources using the stacking techniques in order to obtain new information of lunar internal structure. By stacking many wave forms from an identical seismic source, we could enhance significantly S/N ratio. In the stacked seismograms, we found some significant later phases that include the phate to be identified to be PKP or PKKP core phases. If these later phases are really core phses, it indicates that the lunar core size is approximately 450 km in radius. Since implication of existence of the core phase is so large, we decieded to confirm the existence of core phase in other seismograms. In order to continue this line of research, it is more important and more efficient to construct the data base of the lunar seismograms, because the present Apollo data set is very time-consuming to retrieve and analyze. In order to process many seismograms, it seems essential to construct user-friendly efficient data base of moonquake. This is also true for the data to be obtained during the LUNAR-A mission. Therefore we redirected this research to construct a new moonquake data base. We determined the framework of the data base and implemented. The data base will be widely opened to interested researchers, because this data base is the only source of lunar internal structure. After completion of the data base, we will continue to search for the later phases of deep moonquakes.
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