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Instituto de Investigação
em Vulcanologia e Avaliação de Riscos
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Referência Bibliográfica

ESCUER, M., RIEDEL, C., GASPAR, J.L. (2007) - New 1D velocity models for the Azores with inversion techniques. 5º Simpósio de Metereologia e Geofísica da APMG, Peniche, Portugal, 5 - 8 Fevereiro (Comunicação Oral).


The Azorean archipelago is situated in a triple tectonic junction in the North Atlantic. Its particular geodynamic setting is responsible for a high seismicity and a tectonic controlled volcanism.


The Azores Seismological Surveillance System (SIVISA) was largely improved in the last decade with the installation of new analogue and digital stations, adequate radio transmission links for real-time data acquisition and modern technological facilities for data analysis and storage. As a result of such improvement a higher number of events of lower magnitudes can now be detected and the automation of some analytical processes needs to be enhanced.


The hypocentral location of seismic events strongly depends on the crustal velocity models that are used. The velocity models for the Azores Region that are commonly utilised in routine processes were built after several active seismic surveys with sources and receivers close to the surface that were performed during the seventies. More recently, new geodynamic models were developed following the January 1st, 1980 and the July 9th, 1998 earthquakes and their related seismic crises.


In this work we present a new approach to 1D velocity models for the Azores using data from the SIVISA seismological catalogue. Different seismogenic areas were studied in order to perform several inversion processes.


The purpose of this work was to determine if specific models are needed for different areas in the Azores Region or if they can be generalized to a unique model for the whole archipelago using the Kissling inversion method. It is evident from our studies that the Azores region is very heterogeneous and consequently a number of different models has to be used.