Comparative analysis of distributed acoustic sensing and geophones for multichannel surface wave applications

This paper presents experimental results comparing the application of a Distributed Acoustic Sensing (DAS) system and geophones combined with the Multichannel Analysis of Surface Waves (MASW) technique. The tests were conducted using a 100 m-long telecommunications optical cable and 24 geophones. The excitations were performed using an 8 kg sledgehammer. The results show that the DAS system can estimate the fundamental propagation modes of seismic waves with significant similarity to those estimated by the geophones, leading to the soil classification based on the shear wave velocity profile and accurate determination of the depth of each layer. To achieve this, a signal processing technique - frequency-wavenumber (f-k) domain filtering is applied to the strain signals measured by the DAS system to convert strain into particle velocity.