AN EVALUATION OF EARTHQUAKE GROUND-MOTION SITE EFFECTS AT TWO SITES UNDERLAIN BY DEEP SOILS IN WESTERN KENTUCKY

• Main Author: McIntyre, Jonathan Larry
• Format: Others
• Published: UKnowledge 2008
• Subjects: Amplification Factor|New Madrid|Suspension Logging|EERA|Site Effects; Geology
• Online Access: http://uknowledge.uky.edu/gradschool_theses/562; http://uknowledge.uky.edu/cgi/viewcontent.cgi?article=1566&context=gradschool_theses

Six earthquake acceleration time histories were used to evaluate the groundmotion response of two sites, VSAP and VSAS, near the New Madrid Seismic Zone. These earthquakes ranged in magnitude from Mw 3.6 to Mw 5.2 and were located 46 to 173 km away from the recording instruments. These two sites are underlain by thick sequences (100 and 590 m) of unlithified soil that have been shown to greatly influence earthquake ground motions. Near-surface soil dynamic properties were characterized at the two sites using seismic SH-wave refraction, P-S suspension logging, borehole electrical logs, and geotechnical logging methods. The soil properties were developed into a soil model for each site and the soil models were used to compare theoretical ground-motion models to the actual strong-motion time histories. An 1-D ground-motion simulation program (EERA) was used to complete the theoretical ground-motion analysis. The results of the model indicated that the soils underlying VSAP generated amplification factors of 0.9 to 2.9 at about 6 and 9 Hz. Soils underlying VSAS generated amplification factors of 1.8 to 4.2 at about 5 Hz. These values correlated well with the observations at the two sites.