Level I Investigation Report Eugene Riverfront Development <br />City of Eugene Eugene, Oregon <br />Slope stability Hydrology and drainage Volcanic hazards <br /> <br />Adverse soils Hazardous Minerals Permafrost and freeze-thaw <br /> <br />Land subsidence Erosion and sedimentation Seismic hazards (liquefaction, lateral <br /> <br />spreading, earthquake-induced <br />Subsurface voids Hydrogeology and groundwater <br /> <br />landslides, ground shaking, fault <br />ground rupture, tsunamis and seiches) <br />Specific hazards are presented in Table 1 <br />on our engineering and geological judgment. Where noted, the terminology is taken from a specific source <br />(e.g., HazVu, FEMA). <br />Table 1. Summary of Potential Geologic and Seismic Hazards <br />Geologic and Seismic Hazard Examples Level of Concern <br />Artificial Fill High <br />Expansive Soil Low <br />Adverse Soils Compressible Soil Moderate <br />Organic-Rich Soil Low <br />Sensitive Clay N/A <br />Flooding a Low <br />Hydrology and Drainage <br />Standing Water Low <br />Shallow Groundwater b Low <br />Hydrogeology and Groundwater Seepage and Piping Low <br />Permeability and Percolation Low <br />Ground Amplification c,d Low <br />d <br />Local Fault Rupture Low <br />c,ee <br />Liquefaction and Lateral Spread Low <br />Seismically-Induced Settlement N/A <br />Seismic Hazards <br />Ground Lurching or Cracking Low <br /> <br />Seismically-Induced Slope Instability N/A <br />Tsunami N/A <br />Seiches Low <br />a <br /> Information from the Department of Geology and Mineral Industries (DOGMAI), Oregon HazVu: Statewide Geohazards Viewer, <br /> <br />https://gis.dogami.oregon.gov/maps/hazvu/. Site is not within the FEMA 100-year flood zones. <br />b <br />Groundwater is assumed to be hydraulically connected to the Willamette River elevation. Anticipated to be approximately between 15 <br />feet bgs. <br />c <br />Information from the Department of Geology and Mineral Industries (DOGAMI), IMS-14. <br />d <br />Information from the Department of Geology and Mineral Industries (DOGMAI), Oregon HazVu: Statewide Geohazards Viewer, <br />http://gis.dogami.oregon.gov/maps/hazvu/. Site is mapped as expected earthquake shaking equal to strong <br />e <br />Although DOGAMI mapping indicates a potential for liquefaction at the site, subsurface conditions (i.e., type and relative density of site <br />soils and depth of groundwater) would correspond to a low hazard that will impact the building design and site development. <br />undocumented, variable fill materials. These materials may consist of backfill in the form of dense gravels to <br />debris. Subsurface voids may be encountered due to fill placement and its material types. <br />The primary seismic hazards are liquefaction/lateral spreading. Current mapping shown through the online <br />HazVu program indicates liquefaction may be a potential hazard at the site. However, based on subsurface <br />conditions in the site vicinity and depth to groundwater, our current opinion is that the risk of liquefaction and <br />lateral spreading at the site is low. Liquefaction is a phenomenon whereby shaking of a saturated soil causes <br />its material properties to change so that it behaves as a liquid. <br />April 4, 2019 <br />3 PBS Project 73368.001 <br /> <br />