5 years of GPS observations of the Afar triplejunction area

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• 作者：a ; Andrea Walpersdorf ; Vigny ; Christophe ; Ruegg ; Jean-Claude ; Huchon ; Philippe ; Asfaw ; Laike M. ; et. al.
• 刊名：Journal of Geodynamics
• 出版年：1999
• 出版时间：September 2, 1999
• 年：1999
• 卷：28
• 期：2-3
• 页码：225-236
• 全文大小：1.17 M

文摘

In November 1991, a network of about 30 GPS sites were measuredin Djibouti (Somalian plate). Additional points were also measured in Yemen (Arabia) and inEthiopia (Nubia). Since then, a few points of this network were re-occupied several times ( from January 1993 to March 1995) for short durations. The present day data set includemeasurements from 1991 to 1995 on the large-scale baselines (Arta, Djibouti-Sanaa,Yemen–Addis Ababa, Ethiopia) and repeat measurements on more local baselines in Djibouti.The station of Arta in Djibouti shows very large displacements: locally representative (asattested by a local tie), but different from other stations located on the stable zone outside theoverlap area of the Asal–Tadjoura rifts. This motion does not seem to be linear with time, butrather suggests postseismic deformation (related to the Arta earthquake of March 5, 1992,magnitude 5.4). Except for the episodic Arta displacement, coherent motions of three stations inSouthern Djibouti with respect to Yemen are observed, determining a more stable zone south ofthe overlap area. The observed opening of the Afar triple junction yields at least the NUVEL1-Aestimate of 16 mma between Yemen and Djibouti. © 1999 Elsevier Science Ltd. All rightsreserved.