On the 19th of October, I presented a webinar for the Society of Exploration Geophysicists, covering various aspects of DAS monitoring applied to transport networks. Focusing on things we typically see and the physics behind the signals.
The following link will take you to a recording of the webinar on youtube
DAS is now a standard technology for oil and gas settings, however, fibre optic cables are everywhere so there are numerous other applications for DAS analysis. One such example is the monitoring of activity in transport networks using vibrations detected by DAS surveys. In this talk, I discuss some of the experiences and issues I have encountered in applying geophysical analysis to the monitoring of transport networks using DAS.
With examples from both road and rail traffic I’ll discuss issues such as; the properties of signals from moving vehicles, the influence of the DAS recording geometry, techniques for modelling the recorded signals and how geophysical techniques can be adapted for these settings. In the first example, I will present results from a publicly available DAS data set recorded at Brady Hot Springs in Nevada. This dataset was recorded with the intention of monitoring changes in the underlying geothermal reservoir. However, here I focus has been on using the data to monitor traffic on a nearby highway, providing a workflow to detect and separate vehicle signals. In the second set of examples, I describe the application of DAS to rail traffic monitoring. In particular, I describe how we can model the signals from trains recorded on DAS fibres and how that modelling can assist interpretation. The results can be used (among other things) to analyse train speed, composition, carriage types, and track conditions.
The use of analysis of signals from transport infrastructure is still frontier territory, and there are of course numerous challenges. In this presentation, I discuss some of those challenges from the perspective of a geophysicist and discuss how existing tools can be applied or extended to be part of the solution.