KINEMATICS OF THE ASAL RIFT (DJIBOUTI) DETERMINED FROM THE DEFORMATION OF FIEALE VOLCANO

被引:78
作者
DECHABALIER, JB [1 ]
AVOUAC, JP [1 ]
机构
[1] INST PHYS GLOBE,EQUIPE SISMOTECTON,F-75252 PARIS 05,FRANCE
关键词
D O I
10.1126/science.265.5179.1677
中图分类号
O [数理科学和化学]; P [天文学、地球科学]; Q [生物科学]; N [自然科学总论];
学科分类号
07 ; 0710 ; 09 ;
摘要
Because of its subaerial exposure the Asal rift segment provides an exceptional opportunity to quantify the deformation field of an active rift and assess the contribution of tectonics and volcanism to rifling processes. The present topography of the Asal rift results from the tectonic dismemberment during the last 100,000 years of a large central volcanic edifice that formed astride the rift zone 300,000 to 100,000 years ago. Three-dimensional deformation of this volcano has been quantified from the combined analysis of the topography and geology. The analysis indicates that spreading at 17 to 29 millimeters per year in a N40 degrees +/- 5 degrees E direction accounts for most of the separation between Arabia and Somalia. The small topographic subsidence relative to extension suggests that tectonic thinning of the crust has been balanced by injection and underplating of magmatic material of near crustal density. The methodology developed in this study could also be applied to quantify deformation in relatively inaccessible areas where the main available information is topography or bathymetry.
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页码:1677 / 1681
页数:5
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