In this paper we present a methodology and first results of seafloor compressional sound speed estimation in a compacting passive margin setting of the southeastern Mediterranean Sea, offshore Israel. The estimation was obtained through a coupled wide-angle reflection-refraction travel time analysis of standard commercial 2D multichannel seismic data, acquired with a 7.2km long horizontal receivers array, and geoacoustic inversion. We found that three parameters were needed to model the observed travel times: 1) the compressional sound speed at water-sediment interface c0; 2) a constant velocity gradient K within the sub-bottom sediments layer; and 3) the thickness of the relevant sub-bottom layer H2 . The model considered consists of a water layer with a vertically varying sound speed profile according to the season. The thickness of this layer is constrained by the pre-known seafloor bathymetric depth of 1200 m. The base of the model is the top of a regional salt layer, which underlies the investigated sub-bottom layer and constrains H2 . The estimated c0 and K are 1550 m s-1 and 0.7 s-1 , respectively. The proposed method allows to estimate a relatively low (~1500-1650 m s-1) sound speed at water-sediment interface, where it is challenging to use conventional refraction-based methods.
|Journal||Proceedings of Meetings on Acoustics|
|State||Published - 20 Jun 2021|
|Event||6th Underwater Acoustics Conference and Exhibition, UACE 2021 - Virtual, Online|
Duration: 20 Jun 2021 → 25 Jun 2021
Bibliographical notePublisher Copyright:
© 2021 Acoustical Society of America.
ASJC Scopus subject areas
- Acoustics and Ultrasonics