Active landslides in the Creekside Drive area, Mountain Green, Morgan County, Utah, between June 2005 and December 2006 (RI-260)

By: F. X. Ashland Landsliding in the Creekside Drive area of Mountain Green, Utah, in 2005 and 2006 damaged three houses, a road, and buried utilities, and threatened a buried sewer line, another house, and several other residential lots. The landslides resulted from the total and partial reactivation of preexisting slides in slopes underlain by Tertiary Norwood Tuff. Monitoring by the Utah Geological Survey showed that two of the three largest slides remained active between June and December 2005. Renewed or accelerated movement of the landslides in 2006 was accompanied by the formation of new slides, one of which affected two residential lots and threatened a house. Damaging landslides occurred despite both subdivisionwide and lot-specific, predevelopment, geologic and geotechnical studies by consultants hired by the developer. The earliest study recommended avoidance of the landslide hazard at many of the proposed lots, and adherence to this recommendation would have reduced