Seismic Noise Interferometry and Distributed Acoustic Sensing (DAS): Inverting for the Firn Layer S-Velocity Structure on Rutford Ice Stream, Antarctica

Firn densification profiles are an important parameter for ice-sheet mass balance and palaeoclimate studies. One conventional method of investigating firn profiles is using seismic refraction surveys, but these are difficult to upscale to large-area measurements. Distributed acoustic sensing (DAS) presents an opportunity for large-scale...

Continuous monitoring of the depth of the water‑mud interface using distributed acoustic sensing

Purpose<br/><br/>Current surveying techniques used by port authorities to estimate the nautical depth are limited in depth resolution and temporal resolution. Because of this, certain heavily occupied quay walls cannot be optimised in terms of utilisation. Therefore, a permanent continuous measuring system with a higher depth resolution is...

Distributed Acoustic Sensing: Exploring the potential of unconventional fiber configurations

Over the last decade, Distributed Acoustic Sensing (DAS) has gained increased attention as a cost-effective and practical ground motion monitoring technique, due to the unprecedented temporal and spatial sampling possibilities. Considering these inherent advantages, DAS-collected strain rate measurements can be beneficial as...

Cryoseismic Event Analysis on Distributed Strain Recordings Leveraging Statistical Learning Methods

In the summer of 2020, ETH researchers installed a 9 km long fiber-optic cable on the Rhonegletscher (Switzerland), covering the whole glacier extent from accumulation to ablation zone.<br/>The fiber was then interrogated with a DAS system, turning it into a distributed seismic antenna. The DAS system recorded continuously for one month on more...

Non-Intrusive Characterization and Monitoring of Fluid Mud: Laboratory Experiments with Seismic Techniques, Distributed Acoustic Sensing (DAS), and Distributed Temperature Sensing (DTS)

In ports and waterways, the bathymetry is regularly surveyed for updating navigation charts ensuring safe transport. In port areas with fluid-mud layers, most traditional surveying techniques are accurate but are intrusive and provide one-dimensional measurements limiting their application. Current non-intrusive surveying techniques are less...

Suppression of hydrodynamicand severe slug flow by using surfactants in flowline-riser systems

In the oil and gas industry the occurrence of slug flow in flowlines and risers can cause operational problems. Such flowline-riser systems are used to transport the oil and/or gas from the location of the wells to a production platform, where the fluids might be separated into single phases. Slug flow conditions imposefluctuations in the...