3-D SEISMIC STRUCTURE OF THE CRUST IN THE GULF OF AQABA AND THE SURROUNDING REGIONS | ||
| Journal of Egyptian Geophysical Society | ||
| Volume 6, Issue 1, 2008, Pages 1-16 PDF (1.28 M) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/jegs.2008.380847 | ||
| Author | ||
| M.K. Salah | ||
| 1. Geology Department, Faculty of Science, Tanta University, Tanta 31527, Egypt | ||
| Abstract | ||
| The 3-D P and S wave velocities structures of the crust around the Gulf of Aqaba and the surrounding region have been determined by applying a tomographic method to a large number of arrival times from local earthquakes. From the obtained velocity models we have further estimated the Poisson’s ratio structures in the study area. Using this large data set enables us to accurately image the 3-D crustal structure of this area with a reliable spatial resolution for the first time. We have set a 3-D grid net across the study area with a grid spacing of 0.25º in the horizontal direction and 6 – 10 km, in the depth direction. Strong lateral crustal heterogeneities exist in the study area. At shallow depths, high velocity anomalies are detected at the middle part of the study area. Seismicity occurs in both low and high velocity zones. Low velocity anomalies amounting to 6% are widely distributed in most parts of the Gulf, as well as the areas around it at deeper layers. High Poisson’s ratio anomalies are detected in the northern and northeastern sections of the gulf. Large and small earthquakes occur mostly in areas having average velocities and average to high Poisson’s ratio. Results of the synthetic checkerboard resolution test indicate that, the obtained structures are reliable features. The low velocity/high Poisson’s ratio along the Gulf and adjacent areas indicate the ascending flow of hot upper mantle materials accompanying the opening of the Gulf of Aqaba and the Northern Red Sea. | ||
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