masterThesis
Análise da sequência sísmica de 2017 no Noroeste da Bacia Potiguar
Fecha
2019-12-05Registro en:
FONSÊCA, José Augusto Silva da. Análise da sequência sísmica de 2017 no Noroeste da Bacia Potiguar. 2019. 82f. Dissertação (Mestrado em Geodinâmica e Geofísica) - Centro de Ciências Exatas e da Terra, Universidade Federal do Rio Grande do Norte, Natal, 2019.
Autor
Fonsêca, José Augusto Silva da
Resumen
The understanding of earthquake occurrence in intraplate areas has been one of
the most difficult tasks in Seismology. Attenuation of seismic waves in these
areas is lower compared to border plate regions. As a consequence, even
moderate magnitude earthquakes can represent great hazard. In this case,
assessing the stress field in intraplate regions is important to better understanding
the earthquake generating mechanisms. We analyzed 241 earthquakes of the
2017 seismic sequence in NW Potiguar Basin and estimated the stress regime.
Seismically defined faults were determined for 4 high-precision relocated NWSE- and NE-SW-trending clusters. Faulting intersection acting in one of this
clusters was representative for suggest Intersection model for intraplate
earthquakes as possible explanation about why moderate size earthquake occur
in the study region. Another cluster presented an en echelon fault with a clear
spatiotemporal evolution and occurrence of almost entire activity in very short
period, which suggests energy build-up and rapidly release between this fault
segment. We were be able to calculate composite focal mechanism for three
clusters, with predominant sinistral strike-slip faulting. The inversion of focal
mechanisms reinforce evidence for a superposition of local and regional stresses,
with major compressional axis subparallel to continental equatorial margin.