Mapping Fundamental-Mode Site Periods and Amplifications from Thick Sediments: An Example from the Jackson Purchase Region of Western Kentucky, Central United States

ABSTRACT V S 30 is currently used as a key proxy to parameterize site response in engineering design and other applications. However, it has been found that VS30 is not an appropriate proxy, because it does not reliably correlate with site response. Therefore, the VS30-based National Earthquake Hazards Reduction Program site maps may not capture regional site responses. In earthquake engineering, site resonance, which can be characterized by the fundamental mode with a site period (Tf) and its associated peak amplification (A0), is the primary site-response concern. Mapping Tf and A0 is thus essential for accurate regional seismic hazard assessment. We developed a 3D shear-wave velocity model for the Jackson Purchase Region of western Kentucky, based on shear-wave velocity profiles interpreted from seismic reflections and refractions, mapped geologic units, and digital-elevation-model datasets. We generated shear-wave velocity profiles at grid points with 500 m spacing from the 3D model and performed 1D linear site-response analyses to obtain Tf and A0, which we then used to construct contour maps for the study area. Our results show that Tf and A0 maps correlate with the characteristics of regional geology in terms of sediment thicknesses and their average shear-wave velocities. We also observed a strong dependency of A0 on bedrock shear-wave velocities. The mapped Tf and A0 are consistent with those estimated from borehole transfer functions and horizontal-to-vertical spectral ratio analyses at broadband and strong-motion stations in the study area. Our analyses also demonstrate that the depth to bedrock (Zb) is correlated to Tf, and the average sediment shear-wave velocity (VS-avg) is correlated to A0. This implies that Zb and VS-avg may be considered as paired proxies to parameterize site resonance in the linear-elastic regime.

Effects of stream permanence on stonefly (Insecta, Plecoptera) community structure at Mammoth Cave National Park, Kentucky, USA

Stoneflies (Plecoptera) are often associated with inhabiting cold perennial streams, but many species also inhabit intermittent streams that experience reduced or lack of flow during summer and autumn. In this study, the influence of stream permanence on stonefly assemblage composition and spatial distribution at Mammoth Cave National Park, Kentucky, USA, was addressed, based on a 14 month sampling regime from the fullest range of stream sizes and habitable flow regions available. Adult stoneflies were collected monthly from 43 sites at the Park plus an additional two sites at the near-adjacent Western Kentucky University Green River Preserve. Collections were done from December 2018–November 2019 using a standard timed protocol with beating sheets for adults and once in December 2019–January 2020 for larvae. Stream sites were assigned one of five category types: perennial spring runs, perennial spring seeps, upland perennial streams, perennial riverine and summer dry runs. In total, 34 species were collected. The most prominent difference in stonefly community structure was between spring runs, spring seeps and summer dry streams vs. upland perennial streams. Approximately 88% of species collected had univoltine-fast life cycles and 79% likely had an extended period of egg or larval diapause. Due to the predominance of small upland perennial and summer dry streams, species commonly typically found in larger lotic systems are fundamentally filtered out of the region due to the lack of available habitats. Species able to survive in intermittent habitats do so by life history adaptations including to survive desiccation as larvae or eggs.

The ELALC-SEK Project: Developing English language library classrooms to support literacy learning in the early childhood and primary English language programs at a multilingual Spanish school

Two consultants from Western Kentucky University developed a proposal for and then assisted with the implementation of English Language Arts Library Classrooms in a private Spanish school near Barcelona, Spain. The intent of the project was to enhance the English instruction in the primary grades program at the school. The project involved field observations and a literature review of school libraries in Spain, proposal development, technical assistance, and training in library organization, administration and collection development.