Stability and correlation properties of microtremor response

다국어 초록 (Multilingual Abstract)

This study analyzed microtremor records from four stations located at the center and vertices of an equilateral triangle with 52-m sides. The stability of the horizontal-to-vertical spectral ratio (HVSR) was estimated for 12 days of continuous records. The results showed no variation in the frequency and amplitude of the peak spectral ratio over time. Although the amplitude patterns varied slightly at each station, the peak frequencies were consistent within the small four-station array. The results suggest that slight variations in subsurface structure beneath the array may have influenced the HVSR amplitudes. The HVSR estimate had little or no dependency of meteorological variations in atmospheric pressure, temperature, wind speed, rainfall, and humidity measured at a meteorological observatory approximately 1.3 km from the array. Spatial autocorrelation (SPAC) analyses indicated that time averaging of continuous micrometer records from a single pair of stations could serve as an alternative to spatial averaging for the entire array. This result implies that, with the SPAC approach, microtremor records from a single pair of stations rather than a larger array can be applied.

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