Previous 3D ground-motion simulation studies have demonstrated that the basin structure in Livermore Valley amplifies ground motion due to surface waves generated by the basin-edge effect. To validate the current Community Velocity Model for basin amplification effects, there is a need to map the shallow basin geometry with a higher spatial resolution. In this project, we propose to deploy a 30 km east-west geophone array with 150 m station spacing to record passive seismic signals continuously for two months. We plan to establish a 30-km linear array such that the profile crosses both the Greenville and Calaveras faults and the basin geometry in between could be studied. The profile inside the valley mostly goes through residential areas, and we will seek permission from the residences to deploy geophones in their private yards. The profile extends to the hillsides at both ends of the profile along the public roads where we can easily deploy geophones.