Site response analysis of induced seismic events in the CENA region

Abstract

An investigation of the seismic site response of induced earthquakes, compared to that of natural earthquakes, is presented. A database of 116 ground motions from historic induced and natural events in the Central and Eastern North America (CENA) region, recorded at both the soil surface and bedrock, was developed. Three soil profiles, typical of the CENA region were prepared and equivalent-linear one-dimensional site response analysis was conducted. Parametric studies were performed to assess the differences of ground motion parameters of recorded motions at the surface level, bedrock level, and the associated site response differences between the natural and induced earthquakes. Results suggest that induced earthquakes have the potential to generate spectral amplitudes greater than most natural earthquakes recorded in the CENA region. The mean period of induced earthquakes at bedrock level is typically greater than that of natural earthquakes, for the same peak ground acceleration. Variations in ground motion amplification at specific frequency contents become evident depending on site-specific soil characteristics. Therefore, using natural earthquakes as proxies for induced events, in site response analysis, may not necessarily lead to conservative design scenarios.