For rockfill dams:• The dam material and the underlying soil together form a velocity structure with high speed in the shallow layer and low speed in the deep layer ("low-speed half-space").• The fundamental mode dispersion inversion is more inclined to analyze the velocity structure of the deep fou

A/D conversion: 24-bitDynamic range: 123dBWide voltage recording: maximum support ±10V, adjustable maximum input voltage, not easy to produce clipping.Support multiple sources: controllable source, electric spark source, air gun sourceData acquisition time interval: conventional 500ms, minimum 300ms

Microtremor is a low amplitude (in the order of micrometres) ambient vibration of the ground caused by man-made or atmospheric disturbances. The term Ambient Vibrations is now preferred to talk about this phenomenon.Microtremor is a low amplitude (in the order of micrometres) ambient vibration of th

Surface wave, or ground roll wave, is usually used as a strong amplitude noise that interferes with the reflected signal and needs to be attenuated or eliminated. But the basic idea of this task is to use the dispersion characteristics of surface wave to analyze the surface wave, so as to deduce the