The application of a Dual Accelerometer Vector Sensor for the discrimination of seismic reflections

This paper describes the application of a Dual Accelerometer Vector Sensor (DAVS) for the discrimination between the bottom reflections, the source direct arrival and the source ghost or multipath in an unconventional seismic acquisition scenario. The realisation of the DAVS device and the seismic acquisition scenario described in this paper, were carried out in the scope of the WiMUST project, an EU project, supported under the Horizon 2020 Framework Programme. The WiMUST project aims to improve the efficiency of the methodologies used to perform geophysical acoustic surveys at sea, using Autonomous Underwater Vehicles (AUVs) equipped with optimum sensors. In a classical reflection seismic survey scenario, the DAVS can contribute to this aim by steering its acoustic beam to the desired direction, therefore reducing the amount of post processing related to deghosting and multi-path removal. Moreover, in an unconventional scenario, this steering capability offers the possibility of distinguishing between direct arrivals and multipath. In this paper, using data acquired during a WiMUST experiment, the device's directional estimation capabilities are demonstrated using a conventional beamformer for the determination of the Direction of Arrival (DOA) of seismic waves. The beamformer inputs are pressure and particle velocities in three directions. For the results presented here the pressure was derived from the devices' two accelerometers.