Seismo Lab Brown Bag Seminar

In recent years, Distributed Acoustic Sensing (DAS) has significantly impacted seismology, from earthquake physics to subsurface imaging and monitoring. DAS opens new opportunities across multiple scientific domains by capturing wavefields with unprecedented spatial resolution. While previous studies have shown that well-coupled optical cables can accurately capture ground motion phases, the influence of signal processing and cable characteristics on the DAS instrument response remains unclear.

In this talk, we present a preliminary analysis of DAS instrument response through controlled strain measurements in a laboratory setting. Our experiment involves a ~4-meter optical cable subjected to micrometer-scale deformations induced by a shake table. The table's movements are precisely recorded using a strong-motion sensor, allowing for direct comparison with DAS strain measurements. By systematically varying the excitation frequency, we assess the fidelity of DAS strain retrieval relative to the experimentally imposed strain.

As we move toward analyzing absolute strain amplitudes, accurately characterizing the DAS instrument response becomes crucial. Our findings provide initial insights into the key experimental parameters influencing optical strain signals, laying the groundwork for a more rigorous understanding of DAS system behavior.