Characteristics of the Ambient Seismic Field on a Large-N Seismic Array in the Vienna Basin
Sven Schippkus, Mikaël Garden, Götz Bokelmann
Abstract
Abstract The ambient seismic field is now routinely used for imaging and monitoring purposes. Most commonly, applications aim at resolving crustal-scale features and utilize ocean-generated surface waves. At smaller scales and at frequencies above the microseismic peaks, local sources of seismic energy, often anthropogenic, are dominant, and understanding of their contributions to the ambient seismic field becomes important to apply ambient noise techniques. This study uses data of an industrial-scale seismic deployment covering ∼500 km2 with 10,532 stations, each equipped with several collocated 10 Hz geophones, to provide unique insight into anthropogenic sources of seismic energy in a suburban-to-rural area. We compute amplitude levels, their distance dependency, power spectral densities, and spectrograms to describe the source characteristics. The sources we observe in great detail include windmills, a railway track and trains, cars, oil pumpjacks, power lines, gas pipelines, and airplanes. These sources exhibit time-dependent behavior that is illustrated strikingly by videos of amplitude levels in certain frequency bands that we provide as supplemental material. The data described in this study are a potential resource for future studies, such as automatic signal classification, as well as underground imaging using microseismic noise or the sources presented here.