The behaviour of near‐surface soils through ultrasonic near‐surface inundation testing

ABSTRACT Seismometers installed within the upper metre of the subsurface can experience significant variability in signal propagation and attenuation properties of observed arrivals due to meteorological events. For example, during rain events, both the time and frequency representations of observed seismic waveforms can be significantly altered, complicating potential automatic signal processing efforts. Historically, a lack of laboratory equipment to explicitly investigate the effects of active inundation on seismic wave properties in the near surface prevented recreation of the observed phenomena in a controlled environment. Presented herein is a new flow chamber designed specifically for near‐surface seismic wave/fluid flow interaction phenomenology research, the ultrasonic near‐surface inundation testing device and new vp‐saturation and vs‐saturation relationships due to the effects of matric suction on the soil fabric.