Seismo-turbidites reveal locations of major earthquakes during the past millennium in the Gulf of Aqaba, southern Dead Sea Fault

Date

2024-03-01

Author

Bektaş, Zeynep
Avşar, Ulaş
Ribot, Matthieu
Klinger, Yann
Jónsson, Sigurjón

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Although ample historical and paleoseismological information is available on major past earthquakes along the onland part of the Dead Sea Fault, knowledge of the seismic behavior of its southernmost part in the Gulf of Aqaba has remained limited. To fill this gap and improve our understanding of the seismic potential of the submarine faults in the gulf, we analyzed 18 sediment cores ranging in length from 26.8 to 107.3 cm for sedimentary traces of past earthquakes. Radiographic images of the cores reveal numerous well-preserved turbidites intercalated within bioturbated background sediments. In addition, we used magnetic susceptibility, grain-size and µ-XRF data to detect instantaneous deposition in the sedimentary sequence and stratigraphically correlate the cores along the gulf. These results show coevality of some of the turbidites in cores from different basins of the gulf, which we used as the criterion to assign seismic origin for turbidites. In the top ∼1000 years of the sedimentary sequence, where the spatio-stratigraphical correlations are robust, seismo-turbidites caused by the known earthquakes of 1068, 1212, 1588, 1839, and CE 1995 were successfully detected. We found seismo-turbidites triggered by the 1995 earthquake only in the northern half of the gulf, confirming that this part of the fault system ruptured in 1995. On the other hand, the earthquakes in 1068 and CE 1588 triggered turbidites throughout the gulf, indicating that the entire fault system in the gulf was activated during these earthquakes. In addition, we detected seismo-turbidites of the 1212 and CE 1839 earthquakes only locally, suggesting these were smaller earthquakes. One core containing a sedimentary sequence back to ∼1800 BCE shows likely seismo-turbidites around CE 363, 250 BCE, 850 BCE and 1350 BCE. Together with the 1588 and 1068 earthquakes, these older possible seismo-turbidites may indicate a 400–700 (average = 560) year recurrence interval for large earthquakes in the gulf. Absence of significant turbidites in the southern gulf since CE 1588 therefore implies that this part of the fault system could be a candidate for a large earthquake in the near future.

Subject Keywords

Earthquake, Paleoseismology, Radiographic images, Recurrence interval, Sedimentary sequence, Seismo-turbidites

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https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85184522188&origin=inward
https://hdl.handle.net/11511/108687

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Department of Geological Engineering, Article