UACE2021: Estimating Seafloor Compressional Sound Speed in a Compacting Passive Margin Basin Settings Using Standard Multichannel Seismic Data



    • Day: Wednesday 23rd
        Location / Time: Room A at 16:10-16:30 (EEST, UTC+3)
    • Session: 08. Marine sediment acoustics
      Organiser(s): Ballard Megan, Lee Kevin
      Chairperson(s): Lee Kevin, Chotiros Nick
    • Lecture: Estimating Seafloor Compressional Sound Speed in a Compacting Passive Margin Basin Settings Using Standard Multichannel Seismic Data
      Paper ID: 1467
      Author(s): Uzhansky Ernst, Makovsky Yizhaq, Katsnelson Boris, Copel Shelly, Kazaz Tom
      Presenter: Uzhansky Ernst
      Presentation type: Oral, pre-recorded
      Abstract: In this paper, we present methodology and results of estimations of seafloor compressional sound speed along with sound speed gradient in a compacting passive margin basin (offshore Israel) setting using standard multichannel seismic data (7200 m long array with 576 hydrophones). We use geo-acoustic inversion with three matching parameters: 1) compressional sound speed at the water-sediment interface c_0 , 2) constant velocity gradient K, and 3) thickness of the sub-bottom layer with a constant velocity gradient H_2. A nice feature of the proposed methodology is that c_0,K,H_2 affect travel-time curves differently, so there is only one set of parameters (c_0,K,H_2) that is fully satisfying the travel-time curves from experimental data. The model considered consists of a water layer with a velocity that varies according to the season of data acquisition, lying above a layer in which velocity increases linearly with depth. Estimated c_0 and K, assessed for bottom depths of 1000 – 1350 m, varied from 1500 to 1600 m s-1 and from 0.7 to 0.9 m s-1 per m, respectively, and tend to increase with bottom depth. It was also verified that there is no inter-dependence in the estimation of the different parameters. The proposed method allowed to make assessments of relatively low sound speed speeds at water-sediment interface, where conventional refraction-based methods are not applicable.
    • Corresponding author: Mr Uzhansky Ernst
      Affiliation: University of Haifa, Department of Marine Geosciences
      Country: Israel
      e-mail: