Date

2019-04-12

Author

Jonsson, Sigurjon
Avşar, Ulaş
Bektaş, Zeynep
Castro Perdomo, Ne
Gabriel, Aa
Hanafy, Ss
Klinger, Yann
Lefevre, Mm
Martin, Mai
Masson, Ff
Matrau, Rr
Passone, Ll

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The Dead Sea fault system borders the north-moving Arabian plate and accommodates primarily left-lateral transform motion. Many devastating earthquakes have occurred on the Dead Sea fault during the past 2000 years, with the last major earthquake occurring in Gulf of Aqaba in 1995 (Mw=7.3), causing several fatalities and considerable damage in Egypt and Saudi Arabia. In the Gulf of Aqaba and Strait of Tiran (GAST) area, the Dead Sea fault system is trans-tensional with 3-4 en echelon fault segments within the gulf that bound three major pull-apart basins. Only a part of the GAST fault system ruptured in the 1995 earthquake, while other segments have not ruptured for several centuries. The recent decision of building a bridge between Saudi Arabia and Egypt, spanning Strait of Tiran, and the new city of NEOM has put this area in focus, e.g., with respect to earthquake hazard. To improve our understanding of the tectonics and the level of earthquake activity in the GAST area, we report on an ongoing project aimed at constraining better the location and geometry of active faults in the gulf and its overall tectonics, as well as obtaining new information about how frequent and how large major earthquakes in the area likely are. We have acquired new high-resolution multibeam bathymetric data and are re-analyzing decades of earthquake data to map active faults within the gulf. To get better information about the structure and activity of normal faults bounding the gulf's pull-a-part basins, we have run a seismic survey along a 7 km long profile, crossing one of the faults, and dated samples from uplifted coral terraces along the gulf. In addition, we have installed and remeasured a geodetic GPS network to constrain the moment accumulation rate in the area and collected sediment cores from the seafloor for evidence of pre-historic earthquakes. Finally, we are running scenario calculations to estimate expected shaking levels in future major earthquakes on the GAST faults. We therein specifically acknowledge the new observational constraints as well as complex fault geometries and subsurface structure. Together the results will significantly improve knowledge of the active tectonics in the GAST area and provide valuable information for future seismic hazard assessments.

URI

https://hdl.handle.net/11511/85112

Collections

Department of Geological Engineering, Conference / Seminar