Crustal structure of the Arabian plate: new constraints from the analysis of teleseismic receiver functions

Abstract

We also employed a grid search waveform modeling technique to estimate the crustal velocity structure for seven stations. A jackknife re-sampling approach was used to estimate errors in the grid search results for three stations. In addition to our results, we have also included published receiver function results from two temporary networks in the Arabian shield and Oman as well as three permanent GSN stations in the region.The average crustal thickness of the late Proterozoic Arabian shield is 39 km. The crust thins to about 23 km along the Red Sea coast and to about 25 km along the margin of the Gulf of Aqaba. In the northern part of the Arabian platform, the crust varies from 33 -37 km thick.However, the crust is thicker (41 -53 km) in the southeastern part of the platform. There is a dramatic change in crustal thickness between the topographic escarpment of the Arabian shield and the shorelines of the Red Sea. We compared our results in the Arabian shield to nine other Proterozoic and Archean shields that include reasonably well-determined Moho depths, mostly based on receiver functions. The average crustal thickness for all shields is 39 km, while the average for Proterozoic shields is 40 km, and the average for Archean shields is 38 km. We found the crustal thickness of Proterozoic shields to vary between 33 and 44 km, while Archean shields vary between 32 and 47 km. Overall, we do not observe a significant difference between Proterozoic and Archean crustal thickness. 3We observed a dramatic change in crustal thickness along the Red Sea margin that occurs over a very short distance. We projected our results over a cross section extending from the Red Sea ridge to the shield escarpment and contrasted it with a typical Atlantic margin. The transition from oceanic to continental crust of the Red Sea margin occurs over a distance of about 250 km, while the transition along a typical portion of the western Atlantic margin occurs at a distance of about 450 km. This important new observation highlights the abruptness of the breakup of Arabia. We argue that a preexisting zone of weakness coupled with anomalously hot upper mantle could have initiated and expedited the breakup.

Time-seismicity evolution and seismic risk assessment of the Arabian plate

“…They show that the seismic intensity tends to decreases with time, in agreement with recent estimates on the movement rate [21]. tectonic parameters [6,12,13,26], the historical and recent seismic data recorded by the seismic centers [12,23,24,26], and the extrapolation of the assessment seismic risk of the northern part of the Arabian plate, established by Bilal (2009a) [16], a seismic zoning map for the Arabian plate is proposed ( Figure 5). It distinguishes between three seismic zones: zone 1, associated with the active tectonics of the DSFZ, and the collisional and extensional other zones, the highest seismic zone intensity with major damage risk; zone 3, zone of low seismic intensity, which occupies the core of the whole plate, with lowest potential risk, and zone 2, the intermediary zone with intermediary potential risk.…”

“…tively ( Figure 2). The geophysical investigations confirms the typical continental nature of this plate, with an average crust thickness of 40 Km, which changes, at the level of the Red Sea at 250 KM, to less than 15 Km [6].…”

Rocky Mountain evolution: Tying Continental Dynamics of the Rocky Mountains and Deep Probe seismic experiments with receiver functions

“…[23] The same set of receiver functions used in the H-k stacking technique was utilized in the slant stacking approach by Al-Damegh et al [2005]. This technique is similar to the grid-search-based imaging of Zhu and Kanamori [2000]; however, the uncertainties are estimated in a bootstrap approach [Efron and Tibshirani, 1991;Chevrot and van der Hilst, 2000].…”

Incipient status of dyke intrusion in top crust – evidences from the Al-Ays 2009 earthquake swarm, Harrat Lunayyir, SW Saudi Arabia

“…The low diffusivity is depicting a fractured medium generated due to past intrusions of dykes through which the pore pressure perturbation took place. The existence of mantle plume beneath the western part of the Arabian plate including Harrat Lunayyir has been recognized by several studies (Benoti et al 2003, Daradich et al 2003, Julia et al 2003, Al-Damegh et al 2005 with surface expression of the plume-related ocean-island basalt volcanism (Moufti and Hashad 2005). Pronounced degassing of the CO 2 dominate upper mantle is probably the source of the H 2 O plus CO 2 dominated fluid (cf.…”