Abstract

<p>Seismogenic turbidites are widely used for geohazard assessment. The use of turbidites as an earthquake indicator requires a clear demonstration that an earthquake, rather than non-seismic factors, is the most plausible trigger. The seismic origin is normally verified either by correlating the turbidites to historic earthquakes, or by demonstrating synchronous deposition over large areas of a basin. Correlating historic earthquakes could potentially constrain the seismic intensities necessary for triggering turbidites, however this method is not applicable to prehistoric events. In addition, the synchronous deposition of turbidites cannot be verified for a single core record.</p><p>Here, we propose a new approach to establish the seismic origin of prehistoric turbidites that involves analyzing in situ deformation that underlies each turbidite, as recorded in a 457 m-long core from the Dead Sea depocenter. These in situ deformations have been previously verified as seismites and could thus authenticate the trigger for each overlying turbidite. We also constrain the seismic intensities that triggered prehistoric turbidites by analyzing the degree of in situ deformation underlying each turbidite. Moreover, our high-resolution chemical and sedimentological data validate a long-lasting hypothesis that soft-sediment deformation in the Dead Sea formed at the sediment-water interface. In addition, we use our results to propose seven basic earthquake-related depositional scenarios preserved in depocenters located in tectonically active regions like the Dead Sea. These techniques and findings permit a more confident geohazard assessment in the region and act as a model for other similar tectonic settings, by improving the completeness of a paleoseismic archive.</p>

Highlights

  • IntroductionSeismogenic turbidites are commonly used to derive information such as location, timing, intensity and recurrence intervals of paleoearthquakes, and are vital for geohazard assessment (Goldfinger et al, 2003; St-Onge et al, 2004; Gràcia et al, 2010; Polonia et al, 2013; Strasser et al, 2013; Pouderoux et al, 2014; Ratzov et al, 2015; Moernaut et al, 2018; Hubert-Ferrari et al, 2020)

  • We propose a new approach that involves analyzing the underlying in situ deformations of prehistoric turbidites, as recorded in a 457 m-long core from the Dead Sea center, to establish their seismic origin

  • Our high-resolution chemical and sedimentological data validate a previous hypothesis that soft-sediment deformation in the Dead Sea formed at the sediment-water interface

Read more

Summary

Introduction

Seismogenic turbidites are commonly used to derive information such as location, timing, intensity and recurrence intervals of paleoearthquakes, and are vital for geohazard assessment (Goldfinger et al, 2003; St-Onge et al, 2004; Gràcia et al, 2010; Polonia et al, 2013; Strasser et al, 2013; Pouderoux et al, 2014; Ratzov et al, 2015; Moernaut et al, 2018; Hubert-Ferrari et al, 2020). The use of turbidites as an earthquake indicator requires a demonstration that seismicity is the most plausible trigger, rather than non-seismic factors such as flash floods (Talling et al, 2013; Katz et al, 2015), exceptional discharge (Clare et al, 2016), and storm waves (Paull et al, 2018). This challenge is generally overcome by correlating turbidites with historic earthquakes in a region (Gràcia et al, 2010; Moernaut et al, 2014; Polonia et al, 2016; Wilhelm et al, 2016) or by demonstrating their synchronous deposition in widely spaced, isolated depocenters (Goldfinger et al, 2007; Ratzov et al, 2015; Kioka et al, 2019). The observed deformations in the lake center are similar to seismically induced deformations seen in lakes from other tectonically active regions such as California (Sims, 1973), Anatolia (Avşar et al, 2016), and Southern Italy (Moretti & Sabato, 2007; Vitale et al, 2019)

Methods
Results
Conclusion

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.