NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Press Enter or click the Search button to begin your search.

Back to Results
Moonquake predetermination and tidesA pattern in moonquakes, which correlates with the monthly tidal cycle, also correlates with a phase-shifted pattern of a 7-month tidal cycle. The lead of approximately 2 months in moonquake occurrence can be explained if local tidal forces are combined with a moonquake-driving force. This force, assumed to result from the 6-yr physical libration in latitude, would cause N-S sliding of an outer layer across a solid layer within a decoupled core in a lunar model. During 1969-1971, the sliding would be southward with a progression of monthly maxima in the combined forces. Where these forces control moonquakes, the reversal in direction of the 6-year cyclic force in early 1972 should cause a minimum in moonquake activity. Decreases toward such a minimum did occur simultaneously in the similar progressions of monthly moonquakes and maxima in the combined forces at the most active hypocenter. Repetition of the 1966-1971 force pattern in 1975-1977 should produce a corresponding repetition of the moonquake pattern.
Document ID
19740049589
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Chapman, W. B.
(NASA Johnson Space Center Houston, Tex., United States)
Middlehurst, B. M.
Frisillo, A. L.
Date Acquired
August 7, 2013
Publication Date
April 1, 1974
Publication Information
Publication: Icarus
Volume: 21
Subject Category
Space Sciences
Accession Number
74A32339
Funding Number(s)
CONTRACT_GRANT: NSF GP-6709
CONTRACT_GRANT: NSR-09-051-001
Distribution Limits
Public
Copyright
Other

Available Downloads

There are no available downloads for this record.
No Preview Available