Title: Seasonal Snow Structure and Mechanical Property Estimates through Active-Source Seismology

Program: Geophysics MS

Committee Chair: Lee Liberty

Committee: Lee Liberty, Dylan Mikesell, Hans-Peter Marshall

Abstract: Seasonal snow can exhibit spatial and temporal variability in density, stiffness, and layering. These properties impact snowpack characterization that influences vehicle mobility, avalanche safety, and water management decisions. Thus, traditional point measurement and remotely sensed regional snow data may underestimate the complexity of snow properties at the hundred-meter scale, either by overgeneralizing fine scale variability or simplifying intermediate scale heterogeneity. To address this challenge, I utilize a portable active-source seismic snow streamer system to characterize the mechanical properties of snow at the decimeter vertical scale and decameter horizontal scale. My developed system integrates a towed 24-triplet three-component geophone array (10 cm spacing, 2.3 m aperture) with a compact three-direction push–pull solenoid seismic source. From the recorded data, I can extract first arrival travel times and surface wave dispersion to develop p-wave and s-wave velocity profiles. Additionally, p- and s-wave reflection images reveal internal snowpack structure that are influenced by bulk density contrasts. Field campaigns near Mores Creek Summit, Idaho, Grand Mesa, Colorado, and McCall, Idaho demonstrate acquisition feasibility and highlight velocity differences across sites and snowpack stages (early, mid, and late season conditions). These seismic observations align with independent snow pit and SnowMicroPen measurements, highlighting the method’s ability to resolve snow density and layering variations driven by seasonal weather. These observations may be used to inform policy and procedural decisions.