What is DAS? Fiber Optic Seismology in Theory and Practice

  • Tagungsort:

    Geb. 06.42 - Raum 001 (Seminarraum) / Online

  • Datum:

    10.05.2022

  • Referent:

    Patrick Paitz

    ETH Zürich

  • Zeit:

    9:30 am

  • Quelle:

    Patrick is currently a postdoctoral researcher in the Seismology and Wave Physics (SWP) group at ETH Zürich (Switzerland). His research focuses on Fiber-optic sensing within a geophysical context, ranging from theoretical developments in the field of full-waveform noise inversion with spatial gradients to practical applications of Distributed Acoustic Sensing (DAS) for avalanche dynamics research and hazard monitoring. In the last years, Patrick and his colleagues at ETH Zürich have collaborated with researchers around the world on a wide range of DAS experiments, establishing a strong observational component within the SWP group. 

    Before his Postdoc, Patrick obtained his doctorate from ETH Zürich, following the Idealeague joint MSc. project in applied geophysics and a BSc. in applied geosciences at KIT. 

Abstract

During the last decade, the field of fiber-optic seismology emerged and became increasingly popular for a wide range of geophysical applications, ranging from earthquake detection over volcanology to groundwater monitoring. 
Distributed Acoustic Sensing (DAS) is a method to measure strain (or its temporal derivative) along a fiber-optic cable with unprecedented spatial (<1m) and temporal (kHz) resolution, over distances of up to over 100 km, with a single instrument. This generates a vast amount of data, with single datasets reaching 10s of TBs. 
In this talk, first the measurement technology of DAS will be briefly introduced and compared to existing seismic instrumentation. 
After establishing the foundation and measurement properties of such systems, we will discuss data properties and processing steps that can take advantage of the regularly sampled data (in space), such as data manipulation in the frequency-wavenumber domain.
The last part will give an overview on recent geophysical applications of DAS, with a focus on cryoseismology and alpine mass movements.