Tag Archive for: wasatch fault

good4utah.com

We often talk about “the big one,” hitting the Beehive State.  But now we’re learning it it happens it could mean trouble for Kennecott’s facility on the south slope.

READ MORE

If you missed it a couple of weeks ago, here is an article outlining the paleoseismic study some of our UGS geologists helped with on a trench.

nextcity.org

Not far from I-215 in Salt Lake City, near the airport, a deep trench cuts through the earth. Though it looks like a sewer repair project, there’s nothing down here but dirt. And dirt, to the trained eye, can reveal quite a bit about a city’s future.

READ MORE

The USSC is the central state organization for reducing Utah’s earthquake risk by coordinating efforts, developing public policy, and disseminating results. Here you can find a large earthquake Salt Lake City scenario, and helpful booklet “Putting Down Roots” on preparing for earthquakes. Use the search to find all other USSC documents including photographs and PDFs. Visit the website HERE to help make a plan with your family and friends!

Other helpful links:
Where to Find Earthquake Information
Putting Down Roots PDF

A wonderful resource for earthquake safety and preparedness has just been released. The report was developed by the Utah Chapter of the Earthquake Engineering Research Institute (EERI) and was prepared for the Utah Seismic Safety Commission.

The Scenario for a Magnitude 7.0 Earthquake on the Wasatch Fault-Salt Lake City Segment: Hazards and Loss Estimates report provides information about the effects of the Wasatch fault scenario earthquake-in particular, how long it may take the state of Utah and its residents to fully recover and the potential long-term impacts on Utah’s economy. The ultimate goal of this report is to catalyze public and private actions that will increase pre-disaster resiliency through earthquake preparedness-being prepared to WITHSTAND, to RESPOND, and to RECOVER.

Follow this link to obtain a PDF copy HERE!

OFR-632 insert

By: Steve D. Bowman, Adam I. Hiscock, and Corey D. Unger

This nine DVD set contains a descriptive 8-page report and digital files created from the Wasatch fault investigation project performed for the Utah Geologic and Mineralogical Survey (now the Utah Geological Suvey) and U.S. Geological Survey by Woodward-Lundgren & Associates. The project was performed to identify surface fault rupture hazard areas along the Wasatch fault in Cache Valley. This compilation contains digital scans of three separate Wasatch fault reports, 47 fault maps, and 1382 scanned low-sun-angle-arial photographs (frames). The digital files include aerial photograph scans in TIFF format, fault maps in TIFF and Adobe PDF formats, and index maps in Google Earth KMZ, GIS shapefile and Adobe PDF formats. Specialized software (not included) is required to utilized the Google Earth and GIS files, and can be downloaded from the internet.

This compilation will be useful for professionals involved with paleoseismology investigations; land-use planning and management; government agencies; and the general public and others as a historical archive. Low-sun-angle aerial photography was used to highlight certain topographic features, such as fault scarps and traces, for mapping purposes.

GET IT HERE

Maybe some of you have seen the new movie “San Andreas.” So what could we expect to happen in the event of a giant earthquake on the San Andreas Fault? Read more in this article to find out.

smithsonianmag.com

A giant earthquake will strike California this summer. Skyscrapers will topple, the Hoover Dam will crumble and a massive tsunami will wash across the Golden Gate Bridge. Or at least, that’s the scenario that will play out on the big screen in San Andreas.

READ MORE

Like California, Utah is also earthquake country. One of the best forms of preparation is educating yourself and your family on what to do in the event of an earthquake. For more information on what you can do, see Putting Down Roots, or visit www.bereadyutah.gov.

usgs.gov

A team of scientists from the USGS Geological Hazards Science Center, led by Mendenhall Postdoctoral Fellow Scott Bennett and Research Geologists Ryan Gold, Richard Briggs, Christopher DuRoss, and Stephen Personius are collaborating with scientists at the Utah Geological Survey to gather data from new paleoseismic trenches along the Wasatch fault zone. These new datasets will help researchers to understand if past surface-rupturing earthquakes have spanned fault segment boundaries. They are also analyzing new high-resolution airborne LiDAR topographic data to characterize previously unmapped fault traces and to measure how vertical displacements (vertical offset of the ground surface from faulting) vary, both in space (from north to south) and time (the last 20,000 years).

READ MORE

Utah Faults

Utah has experienced many earthquakes, large and small, because of its abundance of faults and fault zones. Some of the most active faults in Utah include the Wasatch fault along the Wasatch Front, the Hurricane fault in Southern Utah, and the Needles fault zone in Canyonlands National Park.

Visit United States Geological Survey (USGS) Earthquakes or view their Latest Earthquakes interactive map for nation-wide earthquake information.

For Utah-specific resources, visit earthquakes.utah.gov for geologic, preparedness, and local earthquake information.




What is a fault and why is it a concern?


A fault is a break in the earth’s crust along which movement can take place causing an earthquake. In Utah, movement along faults is mostly vertical; mountain blocks (for example, the Wasatch Range) move up relative to the downward movement of valley blocks (for example, the Salt Lake Valley).

Faults with evidence of Holocene (about 10,000 years ago to present) movement are the main concern because they are most likely to generate future earthquakes. If the earthquake is large enough, surface fault rupture can occur.


With a large earthquake (about magnitude 6.5 and greater), the fault rupture can reach and displace the ground surface, forming a fault scarp (steep break in slope). The resulting fault scarp may be several inches to 20 feet in height, and up to about 40 miles in length, depending on the size of the earthquake.

An area hundreds of feet wide can be affected, called the zone of deformation, which occurs chiefly on the downthrown side of the main fault and encompasses multiple minor faults, cracks, local tilting, and grabens (downdropped blocks between faults). Buildings in the zone of deformation would be damaged, particularly those straddling the main fault.

Also, anything crossing the fault, such as transportation corridors, utilities, and other lifelines, both underground and above ground, can be damaged or broken. The ground can be dropped below the water table on the downdropped side, resulting in localized flooding.

Surface fault rupture can also cause tectonic subsidence, which is the broad, permanent tilting of the valley floor down toward the fault scarp. Tilting can cause flooding along lake and reservoir shorelines nearest the fault; along altered stream courses; and along canals, sewer lines, or other gravity-flow systems where slope gradients are lessened or reversed.

On the Holocene fault on which a magnitude 6.5 (approximate) or larger earthquake occurs. On average, these earthquakes may occur once every 120 years on various faults in the Wasatch Front region; once every 350 years somewhere along the central part of the Wasatch fault (between Brigham City and Nephi); once every 2,000 years at any specific locality along the central Wasatch fault; and once every 5,000 to 20,000 years or more on other Holocene faults in the state.

Faults can be avoided by setting homes back a safe distance. Special-study areas have been delineated along faults where geologic studies are recommended to assess the hazard, locate faults, and recommend setbacks. However, the use of special-study areas in land-use ordinances varies by county and city, as does the level of enforcement.

Therefore, buyers, particularly of older homes (pre-1985), should personally check available fault maps to see if the home is near a fault (within a few hundred feet) and, if so, may want a geological site investigation performed. For newer homes, buyers should check with the county or city to determine whether geologic studies were performed for the site or subdivision and, if so, look at a copy of the geologic report.



Survey Notes: Glad You Asked - Earthquake Early Warning System

Wasatch Front Earthquake Early Warning System

Earthquake early warning (EEW) systems work on the principle that an alert signal can be transmitted almost instantaneously, whereas seismic waves take longer to travel through the Earth’s crust. Sensors detect the first-arriving P wave and trigger the sending of an alert signal, which can give people and automated systems some time to take action before the arrival of stronger S waves and surface waves. This diagram illustrates a conceptual EEW system in the Wasatch Front urban corridor.

Read More: What is an Earthquake Early Warning System, and Does Utah Have One?





Exposing the Wasatch Fault

Past large earthquakes on the central, most active segments of the fault and how geologists interpret evidence of large, prehistoric earthquakes, with footage from the North Creek trench investigation.


North Creek Trench on Wasatch Fault

Time-lapse video of the excavation and investigation of the North Creek trench on the Nephi segment of the Wasatch fault zone.


Wasatch Fault Flyby

The Salt Lake City segment of the Wasatch fault and related geologic features.

Recent Utah Earthquakes

University of Utah Seismograph Stations



The Geologic Story of GK Gilbert Geologic View Park

Interactive Story Map



View All Geologic Hazard Maps

Search by County and Hazard Type


Looking for Earthquake Fault Maps?

The new, interactive Utah Geologic Hazards Portal is the gateway to all hazards mapping in Utah. Find the type, location, and relative susceptibility of active faults, landslides, and other geologic hazards where data is available.




In Christchurch, New Zealand in February, 2011, a magnitude 6.3 earthquake struck six miles from the city center. The sandy type of soil present in the area caused the ground to basically liquefy during shaking.

UGS Geologist Chris DuRoss is interviewed by KCPW: Explore Utah Science to discuss the hazard of liquefaction we face right here in the the Salt Lake Valley.

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Earthquake Risk in the Salt Lake Valley

Michael Hylland, a geologist at the Utah Geological Survey, examines disruptions in the subsurface soil at a trench dug through a section of the Wasatch Fault

 

mormontimes.com

If highway construction projects have taught commuters anything, it’s that even a single lane restriction can bring traffic to a crawl. Now imagine the impact on your commute because of a unexpected force of nature — like a strong earthquake, a blizzard, flooding rains or a tornado.

Along Utah’s Wasatch front, a fault spans 240 miles, and 80 percent of Utah residents live along its path.

The Utah Geological Survey notes the fault “has the dubious distinction of being one of the longest and most active normal faults in the world.”

Other areas of the country are also near fault lines. And along the Wasatch fault, several dozen freeway overpasses cross the main corridors near which the fault travels.

Other areas are more prone to conditions that tornadoes form in. And others live in the paths of hurricanes. Still, blizzards, fires and other storms can prompt evacuations or paralyze an area.

READ MORE

MORE INFO

Tag Archive for: wasatch fault

good4utah.com

We often talk about “the big one,” hitting the Beehive State.  But now we’re learning it it happens it could mean trouble for Kennecott’s facility on the south slope.

READ MORE

If you missed it a couple of weeks ago, here is an article outlining the paleoseismic study some of our UGS geologists helped with on a trench.

nextcity.org

Not far from I-215 in Salt Lake City, near the airport, a deep trench cuts through the earth. Though it looks like a sewer repair project, there’s nothing down here but dirt. And dirt, to the trained eye, can reveal quite a bit about a city’s future.

READ MORE

The USSC is the central state organization for reducing Utah’s earthquake risk by coordinating efforts, developing public policy, and disseminating results. Here you can find a large earthquake Salt Lake City scenario, and helpful booklet “Putting Down Roots” on preparing for earthquakes. Use the search to find all other USSC documents including photographs and PDFs. Visit the website HERE to help make a plan with your family and friends!

Other helpful links:
Where to Find Earthquake Information
Putting Down Roots PDF

A wonderful resource for earthquake safety and preparedness has just been released. The report was developed by the Utah Chapter of the Earthquake Engineering Research Institute (EERI) and was prepared for the Utah Seismic Safety Commission.

The Scenario for a Magnitude 7.0 Earthquake on the Wasatch Fault-Salt Lake City Segment: Hazards and Loss Estimates report provides information about the effects of the Wasatch fault scenario earthquake-in particular, how long it may take the state of Utah and its residents to fully recover and the potential long-term impacts on Utah’s economy. The ultimate goal of this report is to catalyze public and private actions that will increase pre-disaster resiliency through earthquake preparedness-being prepared to WITHSTAND, to RESPOND, and to RECOVER.

Follow this link to obtain a PDF copy HERE!

OFR-632 insert

By: Steve D. Bowman, Adam I. Hiscock, and Corey D. Unger

This nine DVD set contains a descriptive 8-page report and digital files created from the Wasatch fault investigation project performed for the Utah Geologic and Mineralogical Survey (now the Utah Geological Suvey) and U.S. Geological Survey by Woodward-Lundgren & Associates. The project was performed to identify surface fault rupture hazard areas along the Wasatch fault in Cache Valley. This compilation contains digital scans of three separate Wasatch fault reports, 47 fault maps, and 1382 scanned low-sun-angle-arial photographs (frames). The digital files include aerial photograph scans in TIFF format, fault maps in TIFF and Adobe PDF formats, and index maps in Google Earth KMZ, GIS shapefile and Adobe PDF formats. Specialized software (not included) is required to utilized the Google Earth and GIS files, and can be downloaded from the internet.

This compilation will be useful for professionals involved with paleoseismology investigations; land-use planning and management; government agencies; and the general public and others as a historical archive. Low-sun-angle aerial photography was used to highlight certain topographic features, such as fault scarps and traces, for mapping purposes.

GET IT HERE

Maybe some of you have seen the new movie “San Andreas.” So what could we expect to happen in the event of a giant earthquake on the San Andreas Fault? Read more in this article to find out.

smithsonianmag.com

A giant earthquake will strike California this summer. Skyscrapers will topple, the Hoover Dam will crumble and a massive tsunami will wash across the Golden Gate Bridge. Or at least, that’s the scenario that will play out on the big screen in San Andreas.

READ MORE

Like California, Utah is also earthquake country. One of the best forms of preparation is educating yourself and your family on what to do in the event of an earthquake. For more information on what you can do, see Putting Down Roots, or visit www.bereadyutah.gov.

usgs.gov

A team of scientists from the USGS Geological Hazards Science Center, led by Mendenhall Postdoctoral Fellow Scott Bennett and Research Geologists Ryan Gold, Richard Briggs, Christopher DuRoss, and Stephen Personius are collaborating with scientists at the Utah Geological Survey to gather data from new paleoseismic trenches along the Wasatch fault zone. These new datasets will help researchers to understand if past surface-rupturing earthquakes have spanned fault segment boundaries. They are also analyzing new high-resolution airborne LiDAR topographic data to characterize previously unmapped fault traces and to measure how vertical displacements (vertical offset of the ground surface from faulting) vary, both in space (from north to south) and time (the last 20,000 years).

READ MORE