Back to CalendarAvinash Nayak of Lawrence Berkeley National Lab presents ERL’s Wednesday Informal Seminar Hour. Determination of source properties of earthquakes and extraction of Love waves from ambient noise using DAS
“The application of distributed acoustic sensing (DAS) to subsurface fiber-optic cables can provide high-resolution, wide bandwidth, and continuous long-duration seismic data over distances of a few tens of kilometers. This talk will demonstrate applications of DAS data acquired on pre-existing unused fiber-optic cables deployed for telecommunication. We demonstrate that mixed-sensor cross-correlation of ambient velocity noise recorded by three-component seismometers and strain-rate noise recorded by DAS arrays permits separate analysis of Rayleigh waves and Love waves. Our results extend the application of DAS to 3D ambient noise Rayleigh-wave and Love-wave tomography using seismometers surrounding a DAS array. DAS data can also be used for studying earthquake source properties in high seismicity regions. We obtain high quality estimates of relative source-time function and relative seismic moment by applying the empirical Green’s function deconvolution method to pairs of co-located earthquakes. Good agreement with results from nearby seismometers demonstrates that DAS dynamic range and bandwidth are sufficient for source studies of small magnitude earthquakes at local distances.”
Dr. Avinash Nayak is a postdoc at Lawrence Berkeley National Laboratory. His current research focuses on various applications of distributed acoustic sensing data in earthquake and ambient noise seismology. He obtained his Ph.D at University of California-Berkeley, working on seismic moment tensor inversion using 3D velocity models, source-type characterization of small magnitude seismic events and hydrothermal tremor signals. Previously, he has worked on body-wave tomography and surface-wave tomography at a range of spatial scales as a postdoc at University of Wisconsin-Madison.