Quantification of Distributed Acoustic Sensing Data Fidelity

Distributed Acoustic Sensing (DAS) has the potential to drastically change ground-motion data acquisition by interrogating a single low-cost fiber optic cable instead of using numerous cost-intensive point sensors.

The attractiveness of DAS lies mainly in its capability to sense strain variations over long distances with very high spatial resolution. The broad-band nature of the measurement is another fundamentally attractive aspect. However, detailed assessments of the sensing performances are lacking, in particular compared to conventional seismometers and geophones.

We present here a number of methods and experiments aiming at characterizing the overall DAS data quality. Noise floor estimates are obtained by comparing data collected from multiple fiber cores in the same cable. Instrumental response and dynamic range are validated via comparison with collocated sensors. The impact of the coupling with the ground is also discussed by comparing multiple cables deployed in different manners. The approaches are based on empirical investigations providing not only qualitative but also quantitative assessments of the DAS data fidelity and can therefore be useful to the growing DAS community in order to benchmark different interrogators.