Cintal logo

Matched-Field Inversion of seismic synthetic data with a short horizontal array (WiMUST Task 3.3)

C. Soares,
A. Mantouka,
P. Felisberto,
SiPLAB, University of Algarve, Campus de Gambelas,
PT-8005-139 Faro, Portugal

Comments: download file (cintal_rep).
Ref.: SiPLAB Report 03/17, SiPLAB, University of Algarve, February 2017.

The WiMUST Project envisions using a team of autonomous underwater vehicles towing short acoustic arrays for seismic surveying of sea-bottom geo-acoustic properties. The idea is to invert the acoustic array data by means of a Matched-Field Inversion (MFI) technique. While there is great deal of experience in MFI and the so-called focalization applied to horizontal propagation scenarios, in near vertical propagation scenarios, with a source receiver horizontal distance limited a few tens of meter or less, there is little understanding terms of feasibility of the acoustic inversion of bottom properties. In particular, when the objective is to simultaneously invert bottom properties (soundspeed, density and attenuation) of multiple bottom layers. The actual simulation study, carried out with an environmental scenario and geometric set up based on the Peljesac data set, models a shallow water acoustic propagation scenario with a short array. A sensitivity analysis in MFI provides understanding on the observability of the unknown parameters of interest. A mismatch analysis indicate that water-column mismatch (soundspeed and depth) may cause the MFI procedure to break down. Based on the conclusions taken from the sensitive and mismatch analysis, an iterative acoustic inversion concept with feedback of intermediate parameter estimates is developed and tested with simulated data.

ACKNOWLEDGMENT: this work was supported by project WiMUST under EU H2020, contract 645141.