Hazard News-Putting Down Roots in Utah’s Earthquake Country Second Edition Provides Updated and New Information

by Emily Kleber, John Good, Adam Hiscock, and Steve Bowman

Putting Down Roots in Earthquake Country

When the ground starts shaking from an earthquake, do you know what to do? Do you know why we have earthquakes in Utah, how we monitor them, and how we mediate their effects? The Utah Seismic Safety Commission (USSC) recently released the second edition of the booklet, Putting Down Roots in Earthquake Country—Your Handbook for Earthquakes in Utah, to help Utahns understand earthquake hazards, and prepare their family, friends, and community for a disaster. This booklet reminds Utahns that a major earthquake does not have to ruin life as we know it—we can take steps as individuals, families, and entire communities to be ready. 

Putting Down Roots in Earthquake Country (a.k.a. “Roots”) was first published for Utah in 2008 and is based on the successful booklets of the same name published by the U.S. Geological Survey for the San Francisco Bay area, northern, and southern California. Similar publications are available for Oregon, Idaho, Alaska, Nevada, and the central United States, and some states also include translated versions for non-English speakers. The last time Roots for Utah was updated was in 2014, when additional scientific data was added. Since then, there have been multiple scientific, preparedness, and engineering advances, as well as several notable earthquakes in Utah, including the March 18, 2020, magnitude 5.7 Magna, Utah, earthquake. In 2021, the USSC decided that the time was right to update Roots with the latest earthquake information available for Utah, with the Utah Geological Survey (UGS) leading the effort. This edition of Roots benefited immensely from strong partnerships with individuals representing organizations making up the USSC. The effort to update Roots was led by the UGS and the Utah Division of Emergency Management (DEM), with input on content from the experts at the University of Utah Seismograph Stations, Be Ready Utah, Envision Utah, the Structural Engineers Association of Utah, the U.S. Geological Survey, and the Federal Emergency Management Agency. This second edition represents countless hours of discussion, editing, and care to bring the best information to the people of Utah. 

This map shows the relative hazard from earthquake ground shaking in Utah. Areas that have experienced several historical earthquakes felt by Utahns, like the Wasatch Front, have the highest hazard. Data source: U.S. Geological Survey

The second edition of Roots contains several new pages that address important topics for the growing state of Utah. Utah’s population is growing on the Wasatch Front, but more people are also moving to areas like southern Utah and Cache Valley, which also have seismic hazards. New pages in Roots address the location of faults, history of past earthquakes in southern Utah and Cache Valley, and note special seismic hazard considerations for each area. Additionally, there is an expanded page on the hazard of liquefaction, which will affect areas having high groundwater levels and could cause an immense amount of damage to critical infrastructure in Utah, like water, sewer, and energy. 

Key updates addressing earthquake probability and response in Utah have been added to the second edition of Roots. A 2016 report from the Working Group on Utah Earthquake Probabilities compiled scientific data to create an “earthquake forecast” for the Wasatch Front. This group determined that there is a 1-in-2 chance (essentially a coin flip) of one or more earthquakes of magnitude 6.0 or larger in the Wasatch Front region in the next 50 years. Additionally, a 2015 report led by the Earthquake Engineering Research Institute and partners indicates the potential losses from a magnitude 7.0 earthquake on the Salt Lake City segment of the Wasatch fault, including economic losses, casualties, and impacts to infrastructure. This report has chilling implications, and the potential impacts have only worsened over time. These facts about our earthquake hazard in Utah are jarring, but knowledge is power, and with proper knowledge, we can address these big issues.

A significant problem for Utah with regards to earthquakes is our history of constructing buildings and homes using unreinforced masonry, mostly as brick. The second edition of Roots includes an in-depth explanation of what unreinforced masonry construction is, how to identify it, how it performs poorly when shaken by earthquakes, and how Utah came to have so much of this dangerous construction for an area with high earthquake hazard. This issue is important in Utah, and one that the USSC has been working hard on for decades. Two recent reports highlighted in the second edition of Roots include the Wasatch Front Unreinforced Masonry Risk Reduction Strategy and the Utah K-12 Public Schools Unreinforced Masonry Inventory. This new information aims to educate readers, inspire them to take proactive steps for themselves and their communities, and to improve unreinforced homes and buildings for all.