Ground Motion Prediction Models for Pennsylvania from Industrial Seismic Sources

Ground motion equations are used in seismic hazard analysis and estimate shaking that could be expected at a specific site during a future earthquake. Such equations are often called attenuation relations and aid our understanding of how ground motion varies with distance. Equations are typically derived using strong- and weak-motion seismograms and the variables that characterize each waveform (i.e., magnitude, source-to-site distance, etc.). Attenuation relations were constructed for eastern North America using ground motion recordings of small-to-moderate magnitude earthquakes observed across geographically broad regions. Associated studies have shown variations in attenuation with distance that deviate from the expected geometric spreading dependence near the source and that transition from local to near-regional effects occurs at various distances. Pennsylvania hosts many mining-related seismic events each year, and a considerable number of local-to-regional distance seismic stations record the corresponding ground motions. We exploit the available industrial data to construct empirical estimates of ground motion attenuation across the Commonwealth and nearby states. Observations from shallow explosive sources are not ideal for assessing potential shaking resulting from earthquakes (mostly deeper shear-faulting sources), but naturally occurring earthquakes are infrequent in Pennsylvania, so we use the data that are available. We measure the peak ground velocity of industrial blasts and use regression to estimate attenuation (geometrical spreading and attenuation), site, and source terms to construct a frequency-dependent ground-motion propagation model for the region.

When and Where Presented: This poster was presented in April 2022 at the annual Seismological Society of America meeting in Bellevue, Washington.