Determination of S-Wave structure via Refraction Microtremor Technique in Urban Area: a Case Study

Geological conditions of Tabriz, a growing city in NW-Iran, are strongly influenced by North Tabriz fault (NTF). North Tabriz Fault is a major seismogenic fault in NW-Iran. So, for a correct seismic microzonation, shear wave velocity (Vs) structure in different part of city should be determined. But urban conditions, such as ambient noise due to cultural activity, restrict the general application of conventional geophysical techniques for determination of Vs. This study proposes Refraction Microtremor (ReMi) technique for determination of shallow shear wave velocity in urban area. The ReMi data were collected by standard refraction equipment at the part of Tabriz city. We used ambient noise including energy from cultural activities and traffic. Also in processing of ReMi, resistivity data, as auxiliary information, are used. At the end for evaluation of results the estimated Vs profile was compared with downhole data that are available around of study area. The findings show that ReMi method is a suitable approach to obtain the Vs structure in urban areas.