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Cratering asymmetry on the Moon: New insight from the Apollo Passive Seismic Experiment
Author(s) -
Kawamura Taichi,
Morota Tomokatsu,
Kobayashi Naoki,
Tanaka Satoshi
Publication year - 2011
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2011gl048047
Subject(s) - impact crater , asymmetry , far side of the moon , geology , apollo , geology of the moon , lunar craters , geophysics , current (fluid) , geodesy , seismology , astrobiology , physics , zoology , quantum mechanics , basalt , biology , oceanography
The synchronous rotation of the Moon can lead to an asymmetry in the cratering rate between the leading and trailing sides of lunar orbital motion. The observation of the Apollo Passive Seismic Experiment can be viewed as a continuous seismic observation of lunar impacts; it provides information of the current bombardments and small impact events of meter‐sized craters. To evaluate the current leading‐trailing cratering asymmetry on the Moon, we investigated the spatial distribution of impact sites determined by Apollo seismic observation. We determined that the number density of impacts on the leading side is substantially higher than that on the trailing side. In addition, we discovered a possible enhancement of the number density of 1.4 ± 0.4 to 1.9 ± 0.5 on the leading side relative to that of the trailing side. This indicated that the cratering asymmetry predicted from historical cratering records also exists in the current low‐magnitude impacts.