Specifications include, but are not limited to:The Northern Region State of Alaska Department of Transportation and Public Facilities, Division of Preconstruction Services, Materials Section is soliciting for professional seismic survey services for the Gerstle and Johnson River Bridge project.; The objectives for the geophysical surveys are as follows: 1) Complete passive seismic surveys at 2 locations at the Gerstle Bridge and 3 locations at the Johnson Bridge; 2) Process the seismic data to deliver a 1-dimensional profile of shear-wave velocity for each survey location; and 3) (Optional) Provide a report with figures showing results. The location for the 1-D seismic profile is the approximate center of each array. See screenshots below for the proposed array locations. A differentially correct Global Navigation Satellite System (GNSS) receiver will provide positioning for all surveys with general horizontal reliability of ±1 foot.