Seminars

03/07/2024 – “Passive Seismic Array Optimization for Application in Gravitational Wave physics” by Dr. Hamid Satari

Abstract: Passive seismic array configuration is a multidimensional problem because the geometric parameters are interrelated and impose a similar but scaled array response across the target frequency band. It is thus challenging to set the array’s parameters optimally for various noise sources at different frequencies, especially for application to gravitational wave detection which is Human’s most accurate measurement in history. Array response function (ARF) analysis and gain maximization are commonly used methods to design a seismic array. The former implies that the larger the aperture, the higher the slowness resolution, whereas the latter requires shorter inter-station distances for higher correlations to improve signal-to-noise ratio.  We have developed an efficient method to deal with this trade-off and design an optimum array for real-time monitoring of the spatio-spectral properties of microseism (0.1–1~Hz) and anthropogenic noise up to the instruments’ latency limit (4~Hz). We use coherence length as a more stable alternative for signal versus noise correlation and benefit from the results of our seismic noise site characterization at the Gingin gravitational wave test facility in Western Australia and design a multi-grid seismic array. ARF simulation results with realistic signal properties considered, indicate the superiority of the proposed configuration over the alternative ones that do not account for the properties of the seismic environment even with the same number of sensors and inter-station distances.

Bio: Hamid started his academic journey by earning a bachelor’s degree in geology in 2009 and finished his post-graduation studies in exploration seismology in 2012 at Tehran University, Iran. He established a geology and geophysics consulting engineering company in 2012 which is still active in Iran. He also worked as a reservoir geophysicist in one of the top 10 oil and gas companies in the Middle East between 2015 and 2019. He didn’t abdicate research while working full time in a way that he developed one of the world’s most efficient time-frequency algorithms in 2017, known as double-sparse S transform which is robust, adaptive, able to attenuate random noise and invertible using only one free parameter. He started his PhD in geophysics at the University of Western Australia in 2019 (supported by CSIRO and Ozgrav) and worked on the application of passive seismic array on gravitational wave detection and finished in 2023 with novel publication results.  He currently works as an acoustic consultant in one of Australia’s top 5 consulting engineering companies in Perth.