Evaluating the present-day kinematics of Azores Triple Junction by combining campaign and permanent GNSS data Abstract


  • Azores Triple Junction is located in the North Atlantic Ocean where three major tectonic plates meet: North America, Nubia and Eurasia. The Mid Atlantic Ridge clearly defines the divergent boundary between the North American plate and the Eurasian and Nubian plates. However, ambiguity about the present-day location of the Azores Triple Point still exists due to the large uncertainties in the present-day location and characteristics of the boundary between the Eurasian and African plates, despite the number of studies already carried out in the past years.
    In this work, we combine data from three CORS GPS stations already available since 2001 with campaign-type GPS observation carried out between 1993 and 2006. Since 1999 that a total of 62 sites were added to the initial network (installed in 1988) of nine stations (one per island). This densification was concentrated on 5 islands located on the Nubia-Eurasia segment of the Azores Triple Junction.
    Existing differences between campaign and continuous observations are evaluated and the reasons discussed. We also focus on the proper relative quantification of associated uncertainties when both type of data are combined to produce an unique velocity-field.
    We investigate the location of the Triple Junction in the Azores using the derived regional GPS velocity field. Results based on the modeling of different geometries for the Eurasia-Nubia plate boundary, favor a wide band of deformation of the Eurasia–Nubia plate boundary connecting Faial and Terceira major fault system alignments with the Azores Triple Point located at the latitude of Faial Island.


publication date

  • 2008

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