February 1, 2007

The Utah Geological Survey (UGS) has released Special Study 119, Paleoseismic Investigation and Long-Term Slip History of the Hurricane Fault in Southwestern Utah, which provides critical earthquake information such as timing, recurrence, and size of large surface-faulting earthquakes along the fault.

The Hurricane fault extends from Cedar City, Utah, to south of the Grand Canyon in Arizona, and is the longest and most active of several large earthquake faults along the boundary between the Colorado Plateau and Basin and Range physiographic provinces. The Utah portion of the fault is subdivided into three segments; each segment can be a separate source of large earthquakes. Two of the segments have experienced geologically recent large earthquakes and accompanying surface faulting. Therefore, the UGS considers the Hurricane fault active and capable of generating earthquakes in excess of magnitude 7.0.

Assessing the seismic hazard of the Hurricane fault is important because southwestern Utah is experiencing a now decades-long construction and population boom, and the fault either passes directly through (Toquerville, La Verkin, Hurricane) or within a few miles of (Washington, St. George, Santa Clara) southwestern Utah’s fastest growing communities.

This report is part of a more extensive cooperative study of the Hurricane fault in both Utah and Arizona by the UGS and the Arizona Geological Survey. The study was funded by the U.S. Geological Survey through the National Earthquake Hazards Reduction Program and by the States of Utah and Arizona.

Special Study 119 is available at the Natural Resources Map & Bookstore for $11.00, 1594 West North Temple, Salt Lake City (801-537-3320, or 1-888-UTAHMAP; geostore@utah.gov).