Dynamic earthquake triggering potential across earthscope's transportable array

The abundance of data from the Earthscope U.S. Transportable Array (TA) eliminates observational barriers such as data paucity and station sampling bias that have in the past hindered our understanding of the processes involved in dynamic triggering. The price of data abundance is that strategies must be developed to automate the systematic recovery of earthquake information. Optimized amplitude threshold detectors in the time-domain used to automate the process of earthquake detection with the TA data result in databases dominated by site-specific noise contributions. To increase the accuracy of detection databases, we develop a frequency-domain detection algorithm that employs spectral characteristics to distinguish earthquakes from other band-limited noise sources. This spectral filtering algorithm doubles the accuracy rate compared to timedomain methods. Despite the improvements in detection accuracy, we find that false detections in single-station pick databases still comprise a majority of all detections from the TA data. Leveraging frequency-domain processing techniques to develop array visualizations enables robust earthquake detection to magnitudes at or below M2. We use this array method to explore 18 global mainshocks (M>7) exhibiting the highest surface wave amplitudes during the TA deployment. Of the 18 mainshocks studied, none show strong evidence of instantaneous dynamic triggering and only one offers limited evidence for delayed dynamic triggering. These results suggest that prolific triggering in the U.S. is a rare phenomenon, requiring amplitudes outside the range observed here and/or that additional conditions (fluids, tectonic environment, frequency, or duration of shaking) within the amplitude ranges explored here play a primary role in dynamic triggering.