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The Mark at Eugene January 6, 2026 Geotechnical Investigation and Seismic Hazard Study 3 Project No.: 2251077 Eugene, Oregon Landmark Construction, LLC FIELD AND LABORATORY TESTING ReMi Shear Wave Velocity Testing A shear wave velocity profile was developed to a depth of 100 feet using the refraction microtremor (ReMi) method. ReMi testing is performed at the ground surface and data acquisition consists of setting up a linear array of geophones and recording ambient seismic “noise”. The testing was completed by Earth Dynamics, LLC on October 31, 2025. The approximate location of the ReMi geophone array and the results of the testing are summarized in the report provided in Appendix E and discussed in more detail in the seismic analysis and evaluation section below. Infiltration Testing Infiltration testing was completed at one location near TP-1 at a depth of ±4 feet. The approximate locations of the infiltration tests are shown on Figure 2A. The drill rig was used to auger to the test depth and embedded into the soil to ensure a good seal. The auger was filled with a minimum of 12 inches of water and left to presoak the soil. Following a presoaking period, the infiltration rate was measured by recording the water level in the casing. The results of the testing indicate an average, unfactored infiltration rate of ±0.6 inches per hour. The infiltration test was performed in the fine-grained alluvium that underlies the site. Based on the likely presence of perched water and relatively shallow groundwater, which will further impact the feasibility of infiltration during wet weather months, we do not anticipate stormwater infiltration at the site will be practical. Laboratory Testing The laboratory testing program included moisture contents and Atterberg limits tests to help classify the soil according to the Unified Soil Classification System (USCS) and estimate their overall engineering properties. The test results are summarized in Table 1C (Appendix C). Non-tested samples were visually classified in general accordance with the procedures outlined in ASTM D2487 and ASTM D2488. The USCS symbols for non-tested samples should be considered approximations. Two, one-dimensional consolidation tests were completed on sample SH-2-3 obtained from BH-2 at a depth of ±8 feet and SH-4-4 obtained from BH-4 at a depth of ±10 feet. The tests were completed to estimate the compressibility of the fine-grained alluvium for use in settlement analysis. The consolidation test reports are shown in Figures 1C and 2C (Appendix C). Data obtained from the tests include the modified compression index (Ccε), modified recompression index (Crε), and preconsolidation pressure (Pc’). These values are summarized in the figures. Field vane shear tests were performed on the Shelby tube samples to estimate the undrained shear strength (Su) of fine-grained soils. The recorded Su values ranged from ±0.6 to 0.88 tons/ft2 (tsf). These values correspond to a stiff soil consistency. The test results are summarized in the boring logs.