The project seeks to constrain near surface seismic velocity structure near the USGS Albuquerque Seismic Lab, which hosts sensors at multiple depths for the GSN station ANMO and a small aperture (~500 m) array of different shallow post-hole and vault installations. New constraints on near surface structure will aid studies of passive methods for estimating near surface structure and analyzing waveform attributes such as polarization. The fieldwork and analysis will involve collaboration between ASL and UNM researchers.