Drone Rules Make Tracking Down Faults a Difficult Feat

Chelsea Scott looks on as Michael Bunds lands a fixed-wing drone in Southern California. Credit: Jui-Chi (Vickie) Lee Source: Drone Rules Make Tracking Down Faults a Difficult Feat - Eos Chelsea Scott and Ramón Arrowsmith, like many earthquake scientists, track down faults. As tectonics researchers at Arizona State University, they need to know where a fault is, how much it’s moved, and how it behaves below the surface. Small uncrewed aerial systems, also known as drones, provide them with high-resolution photographs that capture the necessary information at the scale of centimeters—a higher resolution than some commonly used, easily accessible satellite or airborne data sets. However, collecting drone data along the length of a fault is no simple task. Bigger Is Better A magnitude 7.0 earthquake can produce a 62-mile-long (100-kilometer-long) rupture with surface displacements of up to about 3 feet (1 meter), said Arrowsmith. “You need to have a good enough ruler to measure [that],” he said, which imagery collected from drones can easily provide. The problem, he said, is rapidly covering a 62-mile stretch. Nearly every country that regulates drone operations recommends or requires that pilots maintain visual contact with their drone. One way around the problem is to use a bigger drone. Cheap, heavy quadcopters—helicopters that can easily take off and land—are small compared with lightweight, expensive fixed-wing drones that look like tiny airplanes. In February 2020, Scott and three colleagues spent almost 4 days mapping 25 miles (40 kilometers) of the San Andreas Fault in Southern California. Although they had quadcopters, Scott said “the workhorse was the fixed-wing drone.” “Because fixed-wing drones are so expensive, flight planning is done very, very carefully, and unfortunately the project is over if the drone crashes.” The average quadcopter can be spotted approximately half a mile (0.8 kilometer) away; mapping long linear features like [...]

Landslide Prevention Near Sussex

Source: 'An engineering feat': Why this key section of railway is closed | ITV News Meridian Network Rail describes it as engineering feat, a two week project to stabilize three sections of Victorian railway embankment between Brighton and Hove. Until Saturday October 2nd 120 workers each day are working from up to 15 meters high to install rock bolts, soil nails and netting. All three interventions are designed to protect debris falling onto the tracks. In recent years landslides have led to significant delays for passengers on the network and climate change has made the chalk cutting incredibly vulnerable. Project manager, Tom McNamee says, "We've seen previously catastrophic failures of the embankment and that’s an unplanned failure, we have loose material fall onto the railway and that becomes a danger to trains and essentially we have to close the line in an unplanned, unexpected manor. "We really would like to thank our lineside neighbors, it is a massive inconvenience, we are using chainsaws and rock drills, loud and noisy equipment, right at the. Back of their properties for 14 days but we’re working closely with them and taking in all their concerns and considerations. If we were unable to do this work over 14 days we would have to do this over 12 weeks of night work and that would obviously have a bigger impact on the lives of people living here." 1,012 rock bolts being installed 1,000 soil nails being drilled in £5 million spent on the project Traveling between Brighton and Hove? This is what you need to know Trains between Brighton and London are unaffected No trains will run directly between Brighton and Hove/stations towards Littlehampton Trains will run to an amended timetable between Preston Park and Littlehampton and between Littlehampton and Portsmouth Harbour/Southampton Central Southern passengers will [...]

California Issues Maps of Earthquake Faults to Avoid ‘Potentially Devastating’ Damage to New Buildings

Source: State Issues Maps of Earthquake Faults to Avoid 'Potentially Devastating' Damage to New Buildings - Times of San Diego The Rose Canyon Fault system. Courtesy County News Center Maps released Thursday of earthquake-prone areas are intended to ensure new construction in San Diego does not take place atop dangerous quake faults. Developed by the California Geological Survey, the regulatory Alquist-Priolo Earthquake Fault Zone maps detail where local governments must require site-specific geologic and engineering studies for proposed developments to ensure this hazard is identified and avoided. Generally, new construction for human occupancy must be set back 50 feet from the active surface trace to avoid faults that may break the surface. “Surface fault rupture is the easiest earthquake-related hazard to avoid because you can see the evidence of where it has occurred,” said Steve Bohlen, acting state geologist and head of CGS. “Surface fault rupture means that one side of a fault is moving either vertically or horizontally in relation to the other side. The deformation that movement causes is potentially devastating to buildings and infrastructure.” Two maps of revised Earthquake Fault Zones have been prepared for the Rose Canyon Fault where it comes onshore in Coronado, traversing the San Diego area to the northwest and going back offshore near La Jolla. Each of the maps covers a roughly 60-square-mile quadrangle of territory. The Alquist-Priolo Act was passed into law following the 1971 magnitude 6.6 San Fernando earthquake, which caused extensive surface ruptures that damaged buildings. Not every large earthquake, though, causes surface fault rupture. For example: the Loma Prieta Earthquake of 1989 devastated the Bay Area without breaking the surface. However, the 1992 Landers Earthquake in San Bernardino County caused surface ruptures along 50 miles, with displacements ranging from one inch to 20 feet. “Since the [...]

Dynamic behaviors of wind turbines under wind and earthquake excitations

Source: Dynamic behaviors of wind turbines under wind and earthquake excitations: Journal of Renewable and Sustainable Energy: Vol 13, No 4 Source: How Do Wind Turbines Respond to Winds, Ground Motion During Earthquakes? - AIP Publishing LLC A new study investigates the combined effect of wind and earthquake forces to assess the dynamic behavior of wind turbines. The demand for renewable energy is nowadays at its peak. Wind power is a great source of clean energy and is harvested via wind farms placed in numerous regions across the world. This has led to some winds farms being established in earthquake-prone regions making it important to assess the combined excitation under wind and earthquake forces. In the US, these wind farms are most commonly seen in Alaska, Arkansas, California, Idaho, Illinois, Kentucky, Missouri, Montana, Nevada, Oregon, South Carolina, Tennessee, Utah, Washington, and Wyoming. The study, recently published in the Journal of Renewable and Sustainable Energy, aims at establishing a numerical model that will integrates both seismic, wind, and operation forces of wind turbines to evaluate the performance of the wind turbines. This is referred to as the "fully coupled model". Such models have been tested before but the research team emphasizes that a solid interpretation of the results is still missing. The authors studied a 5MW wind turbine subjected to a combination of wind load and input ground motion with the latter being retrieved from a list of earthquake records. The study provides some interesting findings. The results from the sophisticated numerical models suggest that the wind that acts as a dynamic load for the wind turbine also exerts a damping effect on the response of the structure. In particular, when shaking is strong, the energy absorbed due to the aerodynamic damping is higher than the actual wind loading generates hence, the [...]

University of Nevada, Reno scientists and engineers collaborating on seismic survey for earthquakes

Source: University of Nevada, Reno scientists and engineers collaborating on seismic survey for earthquakes | University of Nevada, Reno University of Nevada, Reno scientists and engineers install equipment at Reno Fire Department's Station 5 on Mayberry Drive as part of a seismic study using fiber-optic cable that runs six miles from downtown Reno to west of Reno. A team of scientists and engineers from the University of Nevada, Reno are installing earthquake sensors above ground along a six-mile stretch of an existing fiber-optic telecommunication cable buried under Reno to develop a rigorous and efficient system for subsurface imaging at the large scale, and detecting earthquakes using laser and fiber-optic technology. "We'll be recording seismic signals generated by passing planes, trains and automobiles along the six-mile stretch of currently unused, buried optical fiber that runs west from Virginia Street along California Avenue and on to Mayberry Drive," Scott Tyler, professor of geological sciences and a leading expert in fiber-optic/laser sensing systems, said. "As the vibrations from the transportation system pass through the underlying geology, it causes a very small change in the optical fiber’s length, which can be recorded from the start of the fiber on South Virginia Street, using a laser-based system called Distributed Acoustic Sensing or DAS." The team, led by Elnaz Seylabi, an assistant professor in the civil and environmental engineering department, is also installing three-component high-resolution seismometers along the cable in the study area to compare traditional methods with the new DAS technology that sends a pulse of laser light through the cable and measures the perturbations in the backscattered light from every point along the cable. The fiber optic system is sensitive enough to detect footsteps as well as jet airplanes that fly by. "Instead of using thousands of geophones to measure ground vibration [...]

Soil Nail Walls Design and Construction

Source: Soil Nail Walls - Design and Construction -NEW (7003IW2022) INSTRUCTOR:  Naresh Samtani, Ph.D., P.E., D.GE, F.ASCE Participants will have access to the virtual workshop video archives and materials for 60 days from the start day of the workshop. Virtual Workshop Brief Using a collaborative and interactive learning approach, this virtual workshop will help you understand the design and construction aspects for soil nail walls. You will learn newer design approaches based on the LRFD platform that is the basis for guidelines for soil nail walls by the American Association of State Highway and Transportation Officials (AASHTO) and the Federal Highway Administration (FHWA). The workshop will help you assimilate the design and construction aspects through active participation by frequent interactions throughout the workshop and real-time expert feedback. The interactions will facilitate a better understanding of the nuances of the newer design principles which would help you avoid costly design errors in real-world projects. In between the two live sessions, attendees will independently work on an application (e.g., exercises) or a reflection (e.g., reading) assignment. Learning Outcomes Upon completion of this course, you will be able to: Explain the terminology for soil nail walls Explain design of soil nail walls using principles of limit state design Explain the essential elements of construction Recognize construction procedures and influence on wall design and performance Explain the importance and concepts of nail testing Identify necessary characteristics of software tools Explain corrosion considerations Discuss facing (shotcrete) analysis Identify the necessary information on plans and specifications Benefits for Participants Become familiar with the latest limit state design approaches and standards for soil nail walls Avoid common pitfalls and costly errors in analysis and design Be able to categorize and streamline limit state evaluation Recognize the importance of considering construction as part of overall design process Assessment of [...]

UD researchers study climate change impacts on soils at military installations

Source: The Ground Underfoot - Civil and Environmental Engineering UD researchers study climate change impacts on soils at military installations We walk over it, drive over it and build on it. Yet, it is probably safe to say, most of us rarely think about the ground beneath our feet. Underneath the grass, concrete, asphalt and other materials in our built environment, however, soil provides structure and stability for what lies above. The United States military wants to understand the role that climate impacts, such as flooding, storm surge or sea level rise, will have on soils at its coastal military bases and facilities, which are critical to national security. Soil conditions can affect the integrity of the ground underpinning buildings, roads, bridges and more. For example, if a soil’s pH were to rise significantly, due to increased salt content-containing ions such as sodium from storm surge, it could create saline conditions that could hamper the ground’s ability to support this necessary infrastructure. Understanding these threats will enable faster and more accurate routing and maneuverability for U.S. forces. The Delaware Environmental Institute (DENIN) is collaborating with the Engineer Research and Development Center (ERDC) of the U.S. Army Corps of Engineers and Louisiana State University to understand how vulnerable military installations along coasts may be affected by soil changes due to sea level rise and coastal flooding. DENIN has received $3.79 million in first- and second-year funding from the U.S. Department of Defense to start this work, and is eligible for an additional $3.82 million in continued funding over the following two years. Led by DENIN Director Don Sparks, Unidel S. Hallock du Pont Chair of Soil and Environmental Chemistry in UD’s Department of Plant and Soil Sciences, the UD effort includes interdisciplinary collaboration with Yan Jin, Edward F. and Elizabeth Goodman Rosenberg Professor [...]

Sichuan China Earthquake

Source: Sichuan, China: Earthquake leaves three dead and 60 injured - CNN An earthquake in China's southwestern province of Sichuan left at least 3 people dead and 60 injured on September 16th, according to China's state-run media. Local authorities put the quake at 6.0-magnitude, while the US Geological Survey (USGS) put it at 5.4-magnitude on an 8-point scale. The quake hit in the early hours of the morning, with the epicenter located about 52 kilometers (32.3 miles) southwest of Yongchuan district in Chongqing, with an initial depth of 10 kilometers, according to USGS. The earthquake left at least 1,221 collapsed houses and more than 3,000 severely damaged homes, according to the Global Times. "I woke up to the tremor and saw the chandelier in my room swinging dramatically and the writing desk was shaking," one resident, surnamed Tang, told the Global Times. "It's been a long time since an earthquake of this magnitude has occurred." Chinese authorities launched rescue efforts in the morning, with the provincial government activating a level 2 response, the second highest in China's four-tier earthquake emergency response system, according to Xinhua. Luzhou City, home to about five million residents, was among the hard-hit areas. Thousands of soldiers and emergency workers have been sent on rescue efforts, along with rescue equipment, medical supplies, makeshift surgical vehicles and heavy machinery. Tents have been set up for evacuees in a nearby village. Experts say a more serious earthquake is unlikely, though there may be aftershocks, Xinhua reported. Sichuan is located along one of several seismic belts in China, which makes it prone to earthquakes. One local employee in Luzhou told the Global Times that though residents are used to earthquakes, they are usually of a lower magnitude -- and Thursday's quake was much stronger than average. A number of [...]

Parameters Variation Model Customization and Sensitivity Analyses

Source: Parameters Variation: Model Customization and Sensitivity Analyses Parameters Variation Model Customization and Sensitivity Analyses A well-known engineering challenge in the framework of finite element (FE) analysis-based design is the large number of input factors involved in geotechnical computational models. There is always a significant amount of uncertainties associated with the properties of geomaterials, being naturally highly heterogeneous materials. In the context of model calibration and validation, conducting a sensitivity analysis is very important. This can determine the key factors which govern the system and efficiently characterize the geotechnical variability for any considered design problem.   Powerful mechanisms for the consideration of parameter variation are also very interesting for speeding up FE model creation and automating results in post-processing. These are also quite useful in reducing model definition for specific types of engineering problems (excavation wall of a specific type under simple ground conditions, simple tunnel shape in uniform rock mass, etc.) to a limited number of parameters that can be inputted in a text file or Microsoft Excel spreadsheet without expert knowledge of the PLAXIS user interface and different modeling techniques and FE know-how. The sensitivity analysis and parameter variation tool in PLAXIS A sensitivity analysis determines how different values of an independent variable affect a particular dependent variable under a given set of assumptions. In other words, sensitivity analyses study how various sources of uncertainty in a mathematical model contribute to the model's overall uncertainty. The Sensitivity Analysis and Parameter Variation tool (see Figure 1) can be used to evaluate the influence of model parameters on calculation results for any particular PLAXIS FE model: The Select Parameters tab sheet will first provide information about all the parameters that can be changed to perform the sensitivity analysis. Available parameters include most model parameters of the data sets for soil and [...]

A Climate Change-Induced Disaster in Denali National Park

Source: A Climate Change-Induced Disaster in Denali National Park | Time The Times has recently showcased an article on the current rockslide situation in Denali National Park. The effects of climate change have been dramatic with the current melting of the permafrost. The National Parks Service has recently upped through gravel removal of the Pretty Rocks Landslide in an effort to keep up as the rapidly thawing permafrost picks up pace. Alaska is right now recognized as the country’s fastest-warming state. The landslide hit unprecedented speed 4 weeks ago causing the team to close the back half of the park weeks earlier than anticipated. This only signals bad news as reservations are canceled in the short term and the long term implications are yet unknown. “This is the canary in the coal mine for infrastructure disruption in Alaska,” says the Camp Denali lodge owner Simon Hamm. “If things continue on the path they’re on, it’s not going to just be Pretty Rock—it’s going to be half of the Alaskan highway system.” Rapid deterioration Denali National Park is one of the U.S.’s largest national parks at 6 million acres, and sits about four hours north of Anchorage. While the entrance to the park is certainly beautiful, many people prefer to hop on buses to access the park’s marquee attractions deep down its single 92-mile road: views of Mt. Denali (formerly Mt. McKinley), the highest peak in North America at 20,000 feet; the gleaming Wonder Lake; rolling mountainsides that contain an abundance of wildlife, including grizzly bears, moose, caribou and bighorn sheep. About halfway along the road lies the Pretty Rocks Landslide, a slowly sliding section of earth that acts more like a glacier than a rockfall. Since the 1960s, permafrost deep below the earth’s surface has thawed, causing the soil and [...]

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