Development of a NEHRP site classification map of Chiang Mai city, Thailand, based on shear-wave velocity using the MASW technique

作者：Thitimakorn Thanop^*

来源：Journal of Geophysics and Engineering, 2013, 10(4): 045007.

DOI：10.1088/1742-2132/10/4/045007

• MASW
• shear-wave velocity
• Chiang Mai
• NEHRP

To account for site amplification and seismic hazard mapping, the shear-wave velocity (V-s) profile to a depth of 30 m (V-s ((30))) is an important parameter and can be used to calculate the ground motion for specific site conditions. In this study, the near-surface V-s profiles of soils were collected at 44 sites in Chiang Mai city using the multi-channel analysis of surface-wave technique. The V-s of each tested location was average weighted to V-s ((30)) based on the National Earthquake Hazards Reduction Program (NEHRP) criteria. The average V-s (30) value of the alluvium soils was about 362 m s(-1), which falls between NEHRP site classes C and D. The average V-s (30) values of flood plain, fluvial clay and natural levee soils (at 300, 299 and 311 m s(-1), respectively) all equated to NEHRP class D. The colluvial deposits in the north-western part of the city were mainly composed of gravel, coarse sand and rock fragments, and were assigned to class C (average V-s (30) of 412 m s(-1)). Soils with lower Vs values will experience higher earthquake ground shaking than those of the bedrock. Accordingly the major part of Chiang Mai city may experience substantial ground shaking due to the amplification in the soft soils.

• 出版日期2013-8