Fuzzy Clustering Analysis of HVSR Data for Seismic Microzonation at Lahore City

A microzonation study deals with the classification of hazards in a town or city terms surface ground motions that result from amplification and resonance frequency soils against seismic tremors. This paper presents peak amplitude for Lahore city, Pakistan. In order to recognize local soil effects covered geology at 159 sites horizontal-to-vertical spectral ratio (HVSR) Nakamura method was implemented. fuzzy C-mean (FCM) clustering algorithm adopted obtain best cluster solution analyzed HVSR parameters. The results Silhouette Index suggest FCM observation data points is more consistent. reveal three solutions. Clusters 1 2 major part research area possesses low moderate frequencies (0.66–1.03 Hz) 2.25–4.38 mm, indicating presence soft hard rock thick alluvial sedimentary cover. Cluster 3 reveals compact rocks (with amplitudes 0.73–1.03 Hz 3.02–4.11 respectively) overlaying bedrock. has 60% cover an 2–3 mm (for central part) about 40% 3–4 northern, southern, southwest portions. According NEHRP code 1997, stiff nature soil, while few places very dense soil. maps produced this will provide expected motion-related useful information reduce risk infrastructure city.