1725 GRAND AVE 2018-01-02 MF Import

, � I . I November 10, 2000 G-1266 Gillette Residence Page 2 3. Soil Conditiona IA review of the geologic map for the area- Prelimingyr GeoloQic Map of the Mukilteo and Everett Ouadran&es. Snohomish County. Washin on-indicate that the project area is underlain by Vashon Till (Qvt) consisting of a very dense mixture of sand, silt and gravel. Based on our site visit on November 7, 200Q we observed an excavation at the north side of the i�ouse and excavations for two footings below the basement floor slab. Accordingly, the soils i encountered at the site wnsist of a dense to very dense brown sand that is more typical of an � Advance Outwash(Qva) deposit, that is typically found below the Glacial Till(Qvt) soils . We used a 3 foot long '/: inch diameter steel rod to probe the sandy sails at the site and found them to be very dense below the basement floor slab, as we could only push the steel probe approximately 1 inch into the sand. The sand is free draining and we did not observe any signs of a shallow groundwater table at the site. I ; 4.0 SEISMICl1'1' j I � 4.1 Puget Soand Seismic Aiatory IThe project site is located within the Seettle metropolitan area. The greater Puget Sound area has � experienced a number of small to moderate earthquakes and occasional strong shocks during the � Ibrief I55-year historical record in the Pacific Northwest. The major earihquakes in the region are i believed to be associated with deep-seated plate tectonic activity. Major faults within the region � Ihave not been active in the Holocene Age(geologic period dating since the last glacial retreat ]0,000 years ago), consequently, none are known to be associated with historical seismicity. IHistorical records for the region indicate that the Olympia earthquake of April 13, 1949, with a Richter magnitude of 7.1, produced ground-shaking of intensiry VIII near its epicenter; and the ISeattle-Tacoma earthquake of April 29, 1965, with a Richter magnitude of 6.5, produced a ground-shaking of intensity IV to VIII on the Modified Mercalli Scale near its epicenter. This I level of ground-shaking is estimated to be the maximum that has occurred in the region during the 155 years of historic record. I Geo Group Northwest, Inc. ��