Dr. Ruijia Wang Seminar: Source discrimination for small-magnitude events (~M1-3) at local scale
Dr. Ruijia Wang
Assistant Professor at the Southern University of Science and Technology
Abstract: Explosions and earthquakes are effectively discriminated by P/S amplitude ratios for moderate magnitude events (M≥4) observed at regional to teleseismic distances (≥200 km). It is less clear if P/S ratios are effective explosion discriminants for lower magnitudes (~M1-3) observed at shorter distances. We report new tests of P/S discrimination using a dense seismic array in a continental volcanic arc setting near Mount St. Helens and evaluated potential controls on local distance P/S ratios including: frequency range, distance, magnitude, source depth, number of seismographs, and site effects. We achieved excellent (with ≥98% true positives and ≤6.3% false positive) discrimination with an optional frequency band of ~10-18 Hz and subsets of at least 16 stations from the cumulative local array. The discrimination ability is further improved if combined with ML-Mc metric (Koper et al., 2021), validated by its application to four different local distance datasets in the US. Lastly, we show how the physical parameters could further assist machine-learning metric toward single-station based discrimination.
Bio: Ruijia Wang is an assistant professor at the Southern University of Science and Technology. Before joining SUSTech, she received her Ph.D. from the University of Alberta in 2018 and worked at the University of Western Ontario for a year, followed by a two-year postdoc at the University of New Mexico. Ruijia is interested in intraplate earthquakes, especially those associated with industrial or human activities. She has published 30 peer-reviewed articles on such topics and served as an editor or reviewer for multiple geophysical journals. She has won several student presentation awards from SSA, AGU, and CGU, and has been recognized as an outstanding reviewer by SRL, JGR, and ERA.
Milligan Room (8th floor LSC Biology Wing)