February 19, 2003

The Utah Geological Survey (UGS) has released a new publication on active faults in Utah. The Quaternary Fault and Fold Database and Map of Utah was compiled by geologists at the UGS and U.S. Geological Survey, and represents the most up-to-date and comprehensive source of information on the 212 known active faults and related geologic structures in Utah.

Most of these faults are considered to be potential sources of earthquakes of magnitude 6.5 or greater. These faults also show evidence for having broken and offset the ground surface in recent geologic time, and are therefore considered to be a surface-faulting hazard in developed areas.

The statewide map is at a scale of 1:500,000 (1 inch equals about 8 miles) and categorizes the faults in terms of the timing of their most recent movement and their slip rate, which is a measure of the activity of a fault. The map also shows where detailed geologic fault studies have been undertaken to determine when past earthquakes have occurred and how big they were.

Armed with this information, scientists can assess the potential hazard associated with future earthquakes and surface faulting.

The database contains a variety of information useful in preliminary evaluations of fault hazards in Utah. The database also reflects how little is known about many of the active faults in the state.

Detailed studies have largely focused on Utah's most active fault, the Wasatch fault, and other faults in or near the densely populated Wasatch Front. With few exceptions, active faults elsewhere in the state have received little to no detailed study.

As Utah's population continues to grow, detailed studies to better understand the hazard associated with these other faults will become increasingly important to ensure safe development.

The Quaternary Fault and Fold Database and Map of Utah, designated as Map 193DM, is available at the Natural Resources Map & Bookstore, 1594 W. North Temple, Salt Lake City (801-537-3320 or 1-888-UTAHMAP; http://mapstore.utah.gov) at a cost of $24.95. The database and map are in digital format (compact disc) to allow interactive use by investigators.

A paper copy of the map ONLY can be plotted for $10.00.