Site effect evaluation for Culiacan, Sinaloa, Mexico

Abstract

Using the spectral ratio technique (HVSR), we performed an analysis of 120 seismic noise records obtained at different points distributed throughout the city of Culiacán, Sinaloa, México. The results show a clear relationship of dominant periods between 0.2 to 0.7 for the alluvium zone in the central and western area of the city and minor periods for points near outcrops of igneous rocks south and southeast of the city. The higher relative amplitudes were found along the riverbed, in the transition zone of conglomerate deposits to alluvium. We performed a multichannel analysis (station arrays) at some points in which we also measured H/V. Afterward, we produced velocity profiles were obtained and transfer functions were calculated. Five of these values were compared with the HVSR technique. Three of them could be compared with the surficial startigraphy obtained in soil mechanics studies to which access was granted.

Keywords

• site effect
• ambient noise
• dominant period
• surface waves
• transfer functions