中科大地球与行星物理学术报告通知-Andreas Fichtner

报告人简介（续）：

Using laser interferometry, these cablesbecome seismic sensors that provide information about Earthstructure and seismicity with unprecedented resolution. in addition to that, Andreas works onhigh-performance computing, medical ultrasound imaging, effective media and metamateriadesign, and non-destructive testing, He is also a co-founder of the ETH Spin-Off Mondaic thatprovides solutions for full-waveform modelling and inversion. For his work, he received the2011 Keiiti Aki Award from the American Geophysical Union, the 2015 Early Career ScientistAward from the international Union of Geodesy and Geophysics, and the 2018 Hoffmann Prizefrom the Bavarian Academy of Sciences.

报告简介：

Fibre-optic deformation sensing provides new opportunities for seismic data acquisitionwith high spatio-temporal resolution. The relative ease of deploying fibre-optic cables, or thepossibility to piggyback on existing telecom infrastructure make this technology particularhattractive for environments where large numbers of conventional seismic instruments may bedifficult to install. These include active volcanoes, glaciers or densely populated urban centres

In the first, more observational part of this talk, we will present a series of case studies whereDistributed Acoustic Sensing (DAS) greatly improved the location of glacial icequakes and ouiknowledge of ice sheet structure, enabled the observation of previously unknown volcanitremor and resonance phenomena, and increased the number of detected seismic events bvtwo orders of magnitude - all relative to data from existing seismometer networks.

In the second, more theoretical part, we will report on the development of two novel fibreoptic sensing systems based on the transmission of laser pulses that enable interrogationdistances of thousands of kilometres. While the first system exploits microwave-freguencysignals, the second system co-uses the active noise cancellation in metrological freguencldissemination. For these kinds of transmission systems, we show that different segments of thefibre can have different sensitivities for deformation sensing, largely depending on fibrecurvature. Data from a large-scale experiments in support this theory and demonstrate thaitransmission-based systems can constrain earthauake source mechanisms using only a singlctime series.