Seismicity of Azores and Geodynamic implications

• Author(s): Borges, J.F. ; Bezzeghoud, M. ; Caldeira, B.
• Date: 2012
• Persistent ID: http://hdl.handle.net/10174/6948
• Origin: Repositório Científico da Universidade de Évora
• Subject(s): Seismicity; Azores; Seismotectonics; Geodynamic; Focal Mechanisms; Seismic strain rates; Seismic moment tensor
• Document Type: Part of book or chapter of book
• Language: English
• Editor(s): Silva, A.M.; Araújo, A.A.; Reis, A.H.; Morais, M.; Bezzeghoud, M.

Description

Over the past thirty years, several seismological studies have been carried out in the Azores region in order to characterize the geodynamic complexity of this region. In this work, we summarize these studies and highlight their main conclusions. The analysis of the focal mechanisms of large earthquakes reveals that there are two zones in the Azores, namely, zones I and II, with different stress pattern and strain rates. In zone I, which is located between 30º W and 27º W, faulting motion corresponds to a left-lateral strike slip with horizontal E-W compression and N-S extension and a strain rate of 6.7 mm/yr. In zone II, which is located between 27º W and 23º W, the seismic moment tensor indicates normal faulting with horizontal NE-SW extension and a strain rate of 3.1 mm/yr..