Finding a niche in geologic hazards

By Dawn Aerts

Iron County Today

CEDAR CITY–If you’re talking landslides, collapsible soils, surface faults or potential hazards, a geologist like Tyler Knudsen is the person to know.

For the past 12 years, Knudsen has found a niche working on these issues with the Utah Geologic Survey (UGS) Southern Regional office in Cedar City. It’s Knudsen’s job to help government officials, geo-technical consultants and the public avoid, or mitigate geologic hazards that may affect existing and future development.

“The most recent projects we’ve worked on are (state-of-the-art) geological mapping of this region,” said Knudsen, who studied geology at the University of Utah before earning his Master’s degree at the University of Nevada Las Vegas. “So, my job is focused on using the detailed mapping (data) to develop geological-hazard mapping for a range of purposes.”

He explains that tech-driven mapping will clarify where faults persist; where landslides have, can, or will occur and where potential and problem soils are located. Knudsen, who was raised in the mostly small farming community of Erda, said he spent much of his free time exploring Southern Utah before he transitioned into a career of assessing geologic-hazards.

“We know that this area was mapped through the 1960s and 70s by federal agencies, but the focus (at that time) was mainly on bedrock with limited attention to the younger deposits and soil features. It’s those (early) deposits you want to understand in greater detail – how its shaped landscapes, and then to identify the specific hazards you may be dealing with.”

Knudsen said that different ages of soil composition and textures tell a very unique story. “One advantage in my mapping this region is that I actually live here… I hike, bike and run in this area – so I have an intimate knowledge of the landscape, unlike previous work that may have been done by (people) without any ‘on the ground’ or local experience.”

According to Knudsen, roughly 50 percent of the geo-mapping project (with detailed case study) is complete. It is that precise data which can and will more accurately determine the potential impact of geo-hazard issues for a wide range of stake-holders – from government planners and homeowners, to mortgage bankers, and real estate investors.

“Unfortunately” said Knudsen of the ongoing work among four UGS field offices, “sometimes the project can be delayed by responding to other geology-related incidence that can be anything from a rock fall at Zion National Park, to a residential development that is facing collapsible soil issues.”

While most geologic-based cases can be mitigated or avoided, he points to a number of building zones that are situated on areas where landslides, falling rock, collapsible soils, and flood-prone areas can and do exist.

“We have seen injuries (with landslides and rock falls) or flooding issues that result in real monetary losses for people. We also know that geological hazards are not only random events,” explained Knudsen. “So we can study a variety of phenomena — where and how often does this occur? And then map those zones with some confidence.”

It’s his job, along with fellow geologists, to assess the pressures of urbanization, the impact of development and hopefully to help the public and developers avoid expanding into hazard-prone sectors by using a unique set of boundaries. “We’ve spent the several years trying to produce comprehensive mapping (an estimated 1,000 square miles for populated areas like St. George and into Zion). The hope is that ‘hazard mapping’ will be used here for better planning and zoning decisions.”

He encourages new residents or developers to call or visit a field office for up-to-date mapping information.

“We know of the collapsible soil issues; the earthquake faults in Hurricane, the landslide concerns in Cedar Highlands and the withdrawal of (fissure-related) groundwater,” said Knudsen, “They are all public safety issues.”

When geo-hazard mapping projects are complete, developers, property consultants and planning officials can use that data as they approve or pursue a project, “we really want to help people avoid building (or investing) in unsuitable or hazard-prone property.”

“I would say we get a fair share of calls from California residents, those who have dealt with the impact of faults and landslides, soil issues and rockslides,” said Knudsen, “So, they’re already accustomed to these issues. In short, people need to do their homework on hazards.”


Photo Caption: Tyler Knudsen, UGS, Southwest Regional Office, devotes his time to geologic mapping to produce practical information on potential geo-hazards that can be avoided or mitigated. The USGS is at work to finalize updated geologic mapping documents (Photo by J. Aerts)

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