15:30 〜 17:00
[HDS05-P10] Sliding characteristics of the Dalun Mountain area, Taiwan using dense microtremor data
キーワード：microtremor measurements, dip slope, Dalun Mountain, Huafan University
The Dalun Mountain area, a dip slope, is a geologically sensitive area with landslides in northern Taiwan. This study deploys microtremor array and single-station measurements, extending from the top of the Huafan University campus to the southwest side, to understand the sliding characteristics around this area. The horizontal-to-vertical spectral ratio, frequency-wavenumber and time-frequency polarization analysis methods are applied to evaluate the landslide thickness, sliding direction and rock mass stability at different slope positions. According to the analysis results, the predominant frequency reflects the depth of the interface between the colluvium and the bedrock (sandstone-shale alternations). Detected sliding depths (15-40 m) were similar to those obtained from well-logging and inclinometer data. In addition, a thicker sedimentary layer appeared at the intersection of the Nanshihkeng Fault and the A Fault at Huafan University. Polarization results also show strong directionality near this intersection point, indicating that this region is relatively unstable, which agrees well with the high strain rates demonstrated by the GPS data. Furthermore, the polarization direction is substantially parallel to the sliding direction (northeast-southwest direction) and perpendicular to the existing surface crack. Besides, we have evaluated the sliding potential at various locations along the slope of Dalun Mountain. Microtremor measurement provides an inexpensive and efficient alternative for investigating the sliding properties of potential landslide areas.