Characterization of Microtremor for The Identification of Subsurface Rivers at Kedung Banteng, Pacitan, Indonesia

Has been conducted research of microtremor characterization based on analysis of curves HVSR, particle motion, and time frequency analysis at Kedung Banteng river system, Pacitan, East Java, Indonesia to identify subsurface rivers using these characters. From particle motion data processing on 12 points of microtremor measurements, in area I, which is a river area, the resultant direction of point TA8, TA9, TA10, and TA13 is NW-SE due to the position of points that is parallel to the stream flow with E-W direction. It can be concluded two things. First, river can be the source of vibration to the point of measurement. Second, direction of particle is perpendicular to the direction of river flow.