Wind gust quantification using seismic measurements

Wind gusts are a major cause of damage to property and the natural environment and a source of noise in seismic networks such as the USArray Transportable Array. Wind gusts cause ground motion through shear stresses, pressure fluctuations and vegetation flexing. Herein, we demonstrate the presence of a seismic response signature to wind gusts at sites across the contiguous USA and explore important geophysical factors that determine the precise nature of wind gust–seismic response relationships. There is a consistent seismic response to wind gusts that is typically manifest at relatively low frequency (0.05–0.1 Hz). However, there is also a marked seasonality in the seismic frequency of peak response, possibly due to seasonal differences in atmospheric conditions and/or vegetation and soil mediation of the atmosphere–ground interaction. The gust–seismic response functions also exhibit a clear dependence on (1) distance from the coast, (2) land cover, (3) topographic complexity and (4) lithology. We propose a generalized methodology to extract wind gust magnitude distributions from seismic networks. Although initial results from this model overestimate the spatial variability in wind gusts as measured by meteorological networks, the analyses described here highlight the potential for new methods to remove wind gust noise from seismic time series and potentially to derive quantitative wind gust estimates from seismic observations.