New paper in Geophysical Journal International by ERL/EAPS Prof. Matej Pec, Principal Research Scientist Dr. Nori Nakata, and former postdoctoral associates Dr. Tong Bai and Dr. Tiange Xing:
https://academic.oup.com/gji/advance-article/doi/10.1093/gji/ggae058/7611703
"As the high-frequency analog to field-scale earthquakes, acoustic emissions (AEs) provide a valuable complement to study rock deformation mechanisms. During the load-stepping creep experiments with CO2-saturated water injection into a basaltic sample from Carbfix site in Iceland, 8791 AE events are detected by at least one of the seven piezoelectric sensors. Here, we apply a cross-correlation-based source imaging method, called geometric-mean reverse-time migration (GmRTM) to locate those AE events. Besides the attractive picking-free feature shared with other waveform-based methods (e.g., time-reversal imaging), GmRTM is advantageous in generating high-resolution source images with reduced imaging artifacts, especially for experiments with relatively sparse receivers. In general, the imaged AE locations are found to be scattered across the sample, suggesting a complicated fracture network …"