Haleh Karbala Ali , Christopher J. Bean

River-induced seismic signal (tremor) recorded by deploying seismic stations close to the river can be used to obtain the flow characteristics of rivers indirectly. This task becomes challenging when the tremor is contaminated by strong cultural noise. We conducted an experiment next to Avoca River, County Wicklow, Ireland. We locate and characterize the river-induced tremor by combining the application of beamforming array analysis, by deploying two seismic arrays, and Frequency-Dependent Polarization Analysis (FDPA) via the deployment of a few single three-component seismometers at different offsets from the river. FDPA on single stations revealed that the tremor consists of Rayleigh, Love, and body waves when it was distinguishable from mixed waves depending on the station's distance from the river. Where Rayleigh waves dominated, we computed the single station back-azimuth (BAZ) of the tremor which was in agreement with the BAZ obtained through array analysis. When wave types are not mixed, we observed that the tremor signal recorded by the stations in the arrays is Love wave-dominated. It was also observed that at time periods of strong cultural noise, the Rayleigh wave component of the tremor emanating from the river is enhanced, suggesting the possibility that surface waves induced by cultural activities get trapped in the river. Moreover, the observation of the correlation between the median filtered seismic power integrated within the frequency range of the tremor and the river flow rate demonstrated the capability of passive seismic as an indirect hydraulic monitoring tool, even in the presence of strong cultural noise.