D. Munkhjargal¹ , O. Chimed¹ , D. Myagmar¹

¹Institute of Astronomy and Geophysics, Mongolian Academy of Science (MAS)

Abstract:

Site effects associated with local geological conditions constitute an important part of seismic hazard assessment. This work was done in the framework of the project "Seismic micro zoning 12 aimag centers" funded by Ministry of Construction and Urban development. In order to estimate site effects we used seismic weak motion, seismic noise survey and seismic array measurement data. The weak motion survey was applied for 15 sites including 1 outcropping rock site used as reference site with a duration of 14 days. Other 14 site locations were selected based on different geotechnical conditions. Seismic microtremor measurements were done in a 500 meter distance grid and in total 527 sites were measured for a duration of one hour. All measurements were done with a Guralp CMG3EPS seismometer and REFTEK 130b digitizer. For all noise and weak motion measurement sites we obtained the amplified frequency using Horizontal to Vertical noise spectral ratio (HV). With this ratio we defined for each site a geological condition area. Based on this we created a deduced amplified frequency map.