Wind‐induced microseisms from Lake Ontario |
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| Authors: | Bryan R Kerman Robert F Mereu |
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| Institution: | 1. Lake Meteorology Laboratory, Atmospheric Environment Service , Canada Centre for Inland Waters , Burlington, Ontario;2. Department of Geophysics , University of Western Ontario , London, Ontario |
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| Abstract: | Abstract The characteristics of microseisms measured in four vaults of the Southern Ontario Seismic Network within 30 km of the shore of Lake Ontario are analysed. It is shown that the rms values in the 1–3 Hz band are coherent between the stations, indicating a common generative mechanism. A distinct onshore intermittent flux of Rayleigh‐like wave energy was detected at a site near the shore. Microseismic energy in this band is distinctly correlated with the wind speed. The incremental microseismic energy above an absolute minimum activity as a function of wind direction, for a given fixed wind speed, correlates with the average fetch of the wind over the lake, indicating that the source of microseisms is the lake itself. The sensitivity to fetch effects is similar for both onshore and offshore stations indicating that shoaling is probably not a source. Niagara Falls, which also can have a wind‐dependent flow from Lake Erie, causes a measurable effect to at least 25 km but does not significantly affect stations at a distance of 150 km. |
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