ASSESSING THE APPLICABILITY OF L-SHAPE ARRAY FOR MICROTREMOR SURVEY
Supervisor: Toshiaki YOKOI
effects play a major role in destructive ground motion. The effects of local
geology may modify ground motion significantly on soft soils.To evaluate the
site response, Microtremors methods have advantages: low cost and environment
friendly for urban area and effective for low or moderate seismicity area. But
standard array shape is strict circular. In urbanized area, it is usually very
difficult to find an area for circular array observation due to existing
buildings and other facilities. Therefore, irregular array should be
investigated and in the paper L-shape array was checked by comparing the
performances of circular array and L-shape array (both even and uneven
interval) in the same site. The SPAC coefficients fit well with theoretical
Bessel function, so the results are reliable. The results show that L-shape can
have good performance in microtremors surveying. A shear wave profile was
obtained by L-shape array and had good agreement with existing borehole data.
The theory of Shiraishi et al.(2006) was attested by the observation data.
Moreover, an effective and efficient method for the key step of SPAC analysis,
frequency range selecting, was proposed.
|Citation: ||Bulletin of IISEE, 44, 1-6.|