Determining the site effects of 23 October 2011 earthquake (Van province, Turkey) on the rural areas using HVSR microtremor method

Abstract

A magnitude of 7.1 Mw earthquake struck Van city on October 23, 2011. Although, construction practices of all rural housing units are similar in the region, the earthquake caused massive damage to villages located on soft soils in northern region of the city. In this study, the effects of soil conditions on damaged housing units were determined by conducting horizontal to vertical spectral ratios of microtremor (HVSR) measurements. The level of damage in the villages that are settled on lacustrine and stream sediments has verified that the damage correlates well with comparatively high HVSR peak period and HVSR peak amplitude values in the range of 0.2-1.6 s and 4-10, respectively. The HVSR peak period and HVSR peak amplitude levels on rock units are in the range of 0.1-0.2 s and 1.5-2, respectively. It is important to note that hillside effect is found to be another key factor that increased the level of damage to the housing units in some villages.