Abstract

• Determination of local Site effect had carried out at 43 sites in Dagon Township, Yangon, Myanmar. Yangon area is located in moderate to high seismic prone area and high damage can be expected because the soil conditions in the city vary from alluvial soil to soft rock. The potential damage effects can be estimated on the basic of local soil effects. To determine the local soil conditions and its effects, analysis of the ratio of horizontal to vertical (H/V) spectra of microtremor was performed. The microtremor measurements were conducted by the SMAR-6A3P seismograph with LS-8800 data logger and GPS time composition at 200 Hz sampling rate. Finally, sediment thickness, shear wave velocity structures and potential soil amplification were determined. The potential frequency is ranging from 1.25Hz to 2.65Hz and the amplitude is ranging from 0.2 to 3.8. The potential soil thickness is ranging from 52 m to 106 m and average shear wave velocity of upper 30m depth, Vs 30 , is ranging from 200 m-1 to 540 m-1 in general. Microtremors analysis show that southeastern and northwestern part of the Dagon Township is covered by thick and soft sediments (low frequency and high peak amplitude) while the central part of the Dagon Township is generally covered by thin and soft sediments (high frequency and high peak amplitude). These results can be used for urban seismic hazard assessments and risk mitigations in future.