A newly-released set of maps identifies numerous geological hazards in the Zion National Park area.
The maps and accompanying report, released in 2013 by the Utah Geologic Survey division of the Utah Division of Natural Resources, point out numerous geological hazards that threaten communities near Zion National Park in Washington County, Utah. The Utah Geologic Survey produced the maps to inform local land owners and municipal planners about the locations and types of geographical hazards that exist in the area.
The hazards have the potential to damage existing and future structures in the communities of La Verkin, Virgin, Rockville, and Springdale. They include earthquakes, flooding, landslides, rock falls, collapsible soil, expansive soil and rock, surface faulting, liquefaction, soil piping, erosion, and wind-blown sands.
In recent years, the area has experienced many landslides and dangerous rock falls, a major earthquake, and frequent flooding of the Virgin River. High clay content in the soil causes landslides and the abundance of weak sedimentary rock makes rock falls common. The region is located between the Hurricane and Sevier Faults, making it prone to earthquakes. Earthquakes can set of massive landslides like the Springdale landslide of 1992, which knocked out power and destroyed roads. These combined geological factors, along with many others, create a very hazardous region.
Three of the four communities in the area (Springdale, Virgin, and La Verkin) have experienced much growth in past years and are projected to grow rapidly in the future. The authors of the report say that the maps will inform construction planners what hazards they will encounter in certain areas and help them determine where it is safe or unsafe to build.