Título:	Insights about deep moonquakes origins
Autor(es):	Silverio, Lyara Villanova
E-mail do autor:	lyaravillanova@yahoo.com
Orientador(es):	Yokoyama, Elder
Assunto:	Lua Sismos lunares Profundo Sismicidade Periodicidade Ciclicidade Mecanismo físico
Data de publicação:	28-Out-2021
Data de defesa:	30-Jul-2021
Referência:	SILVERIO, Lyara Villanova. Insights about deep moonquakes origins. 2021. 107 f., il. Dissertação (Mestrado em Geociências Aplicadas) — Universidade de Brasília, Brasília, 2021.
Abstract:	The genesis of deep quakes has been challenged scientists for decades. Fifty years after the Apollo 11 mission, some questions on the geophysical characteristics of the Moon still remain unanswered. One of them involves the casual mechanism of deep moonquakes, which are low magnitude seismic events (M ≤ 2) that ranges from 700 km to 1200 km in depth. Although the interpretation of seismological data from the Apollo Missions has provided essential infor- mation on the composition and structure of the Moon, a relationship between this structuration and how the gravitational forces in the Earth-Moon-Sun system influence deep moonquakes is still unclear. Previous studies suggest that these deep quakes can be triggered by gravitational variability, produced by the motion of the Moon around the Earth (such as the synodic, anoma- listic, and sidereal periods/months), i.e., tidal periodicity. Deep moonquakes, for example, have been associated with lunar orbital cyclicity. However, cyclic tidal stress is not sufficient to cause rupture at confining pressures where deep moonquakes occur, since its hypocenters occur in deeper areas and may not be sensitive to tidal stress. On Earth, deep quakes occur close to the transition zone in the mantle and their origin is often associated with dehydration of lithospheric slabs. Also, the angle relation between the lunar apse parallel to the axis of rotation of the Earth has been associated with an increase in the number of large earthquakes, due to tidal stresses. Here was analyzed a time series of deep moonquakes (correlating with deep earthquakes) with the number of seismic events per day, and calculated correspondent orbital parameters, such as variations in distance, angular and temporal occurrence between the Moon and the Sun-Earth orbital planes. This analysis was performed using Machine Learning and Wavelet approaches. In contrast to previous studies, the results suggested that the orbitals elements subject to solar disturbances do not significantly influence deep moonquakes. Alter- nately, deep moonquakes are mainly related to orbital parameters that describe the position of the Moon in its orbital plane, in relation to the coordinate system referenced by the ecliptic and equinox of the J2000.0 epoch (where Apollo missions recorded all the events that we know). The results show that deep quakes are triggered by the movement of the Earth and the Moon in their own orbital plane. Here was found that deep seismicity arises from the orbital movements of Inclination of the lunar plane (IN), Longitude of Ascending Node (OM), True Anomaly (TA), and Argument of Perifocus (W). Deep quakes occur in specific seismic regions suggest- ing that seismicity may be induced by external factors to the planetary body. These results also suggested that the Earth and the Moon have specific layers with elastic behavior that respond seismologically in a similar way.
Unidade Acadêmica:	Instituto de Geociências (IG)
Informações adicionais:	Dissertação (mestrado) — Universidade de Brasília, Instituto de Geociências, Programa de Pós-Graduação em Geociências Aplicadas, 2021.
Programa de pós-graduação:	Programa de Pós-Graduação em Geociências Aplicadas e Geodinâmica
Licença:	A concessão da licença deste item refere-se ao termo de autorização impresso assinado pelo autor com as seguintes condições: Na qualidade de titular dos direitos de autor da publicação, autorizo a Universidade de Brasília e o IBICT a disponibilizar por meio dos sites www.bce.unb.br, www.ibict.br, http://hercules.vtls.com/cgi-bin/ndltd/chameleon?lng=pt&skin=ndltd sem ressarcimento dos direitos autorais, de acordo com a Lei nº 9610/98, o texto integral da obra disponibilizada, conforme permissões assinaladas, para fins de leitura, impressão e/ou download, a título de divulgação da produção científica brasileira, a partir desta data.
Agência financiadora:	Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES).
Aparece nas coleções:	Teses, dissertações e produtos pós-doutorado

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