US: Magnitude-6.5 earthquake occurs east of Chignik, Alaska

Source: US: Magnitude-6.5 earthquake occurs east of Chignik, Alaska Oct. 11 A magnitude-6.5 earthquake occurred off the eastern coast of Alaska Peninsula at around 01:10 AKDT Oct. 11. The epicenter was about 114 km (70 miles) east of Chignik. The tremor occurred at a depth of about 46 km (28 miles). Moderate shaking was likely felt across northern parts of the Aleutian Islands and much of Kodiak Island. There have been no initial reports of damage or casualties as a result of the earthquake; however, significant damage is unlikely. It could take several hours until authorities can conduct comprehensive damage assessments, especially in remote areas. Aftershocks are likely over the coming days. Authorities have not issued any tsunami advisories. Officials may temporarily shut down transportation infrastructure in the tremor zone to check for damage. Minor disruptions could occur during shutdowns, but service will likely resume quickly if no damage is found. Utility outages are possible, particularly near the earthquake's epicenter.

California agency finds significant liquefaction

Source: State agency finds ‘significant liquefaction’ | Local News Stories | The green in this map indicates areas on the coast that may be prone to liquefication, according to the California Geological Survey. Illustration courtesy California Geological Survey The California Geological Survey last week released new hazard maps for San Mateo and Contra Costa counties that detailed where landslides and soil liquefaction could likely occur in the event of a significant earthquake. The CGS’s Seismic Hazard Zone maps found “significant” liquefaction zones in parts of San Mateo County, particularly in Half Moon Bay, Miramar and San Bruno. The state has already mapped most of the Peninsula, including Montara Mountain, Woodside and San Mateo. But La Honda and San Gregorio are two notable rural areas that don’t have data accessible yet. Each map, a roughly 60-mile zone called a “quadrangle,” accounts for three types of geologic issues caused by earthquakes: a fault rupture, landslide and liquefaction, which describes the process when seismic tremors cause soil to mix with groundwater and behave like quicksand. The state agency identifies most of the city of Half Moon Bay as inside a liquefaction zone. Its quadrangle is 74 square miles, and the liquefaction zone spans the city’s entire coastline and more, including most of the neighborhoods up to Pilarcitos Creek, including El Granada, Miramar and rural areas like Purisima Creek Redwoods Preserve. The map also identifies fault zones on both the east and west sides of the Half Moon Bay Airport, and more than half of Montara Mountain’s quadrangle is at risk of earthquake-induced landslides. The CGS maps were drafted in February but became official on Sept. 23. Land management agencies and cities use hazard maps to identify properties that require site-specific studies before breaking ground on new development. [...]

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 [...]

Earthquake: 6.1 quake registered near Adak, Alaska

Source: Earthquake: 6.1 quake registered near Adak, Alaska - Los Angeles Times A magnitude 6.1 earthquake was reported Friday morning at 4:52 a.m. Pacific time 114 miles from Adak, Alaska, according to the National Oceanic and Atmospheric Administration’s Tsunami Warning System. According to the USGS, the epicenter was more than 100 miles from a city. In the past 10 days, there have been two earthquakes of magnitude 3.0 or greater centered nearby. The earthquake occurred at a depth of 31.1 miles.

International Conference on Earthquake Geotechnical Engineering ICEGE in February 2023 in Paris

Source: International Conference on Earthquake Geotechnical Engineering ICEGE in February 2023 in Paris The International Research Conference Aims and Objectives The International Research Conference is a federated organization dedicated to bringing together a significant number of diverse scholarly events for presentation within the conference program. Events will run over a span of time during the conference depending on the number and length of the presentations. With its high quality, it provides an exceptional value for students, academics and industry researchers. International Conference on Earthquake Geotechnical Engineering aims to bring together leading academic scientists, researchers and research scholars to exchange and share their experiences and research results on all aspects of Earthquake Geotechnical Engineering. It also provides a premier interdisciplinary platform for researchers, practitioners and educators to present and discuss the most recent innovations, trends, and concerns as well as practical challenges encountered and solutions adopted in the fields of Earthquake Geotechnical Engineering Call for Contributions Prospective authors are kindly encouraged to contribute to and help shape the conference through submissions of their research abstracts, papers and e-posters. Also, high quality research contributions describing original and unpublished results of conceptual, constructive, empirical, experimental, or theoretical work in all areas of Earthquake Geotechnical Engineering are cordially invited for presentation at the conference. The conference solicits contributions of abstracts, papers and e-posters that address themes and topics of the conference, including figures, tables and references of novel research materials. Guidelines for Authors Please ensure your submission meets the conference's strict guidelines for accepting scholarly papers. Downloadable versions of the check list for Full-Text Papers and Abstract Papers. Please refer to the Paper Submission Guideline, Abstract Submission Guideline and Author Information before submitting your paper. Conference Proceedings All submitted conference papers will be blind peer reviewed by three competent reviewers. The peer-reviewed conference proceedings are indexed in the Open Science Index, Google Scholar, Semantic Scholar, Zenedo, OpenAIRE, BASE, WorldCAT, Sherpa/RoMEO, and [...]

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 [...]

ASU Receives Western States Seismic Policy Council Award in Excellence

Source: Sustaining solid ground | ASU News   A team of faculty members and students in the Ira A. Fulton Schools of Engineering at Arizona State University contributed to a major geotechnical engineering field research project recently recognized with a 2021 Western States Seismic Policy Council Award in Excellence. Associate Professor Leon van Paassen led the group from ASU’s Center for Bio-mediated and Bio-inspired Geotechnics, in a collaboration with researchers from Portland State University and the University of Texas at Austin. The endeavor has been funded by the Natural Hazard Engineering Research Infrastructure program of the National Science Foundation. Recent ASU civil engineering doctoral graduate Elizabeth Stallings Young (second from the right) is shown with Portland State University students and staff members involved in characterizing soils near the Portland International Airport, one of two main sites for a major soil liquefaction research project supported by the National Science Foundation. Van Paassen and Professor Edward Kavazanjian, director of the Center for Bio-mediated and Bio-inspired Geotechnics, have collaborated on projects to reduce the impact of earthquakes on soils. One of these aftereffects is liquefication, or the process by which soil saturated with water loses strength, which can lead to ground failure. ​The multi-university project involves microbially induced desaturation — called the MID technique — for mitigation of earthquake-induced liquefaction in silty soils. Photo by Leon van Paassen/ASUDownload Full Image Seeking earthquake and engineering solutions The work has included treating two test sections located within the Port of Portland Critical Energy Infrastructure hub (the Harborton site) and adjacent to Portland International Airport (the Sunderland site). The map shows two sites in the vicinity of Portland International Airport and the Port of Portland Critical Energy Infrastructure hub that are test sections for the research to develop techniques for reducing soil damage as a result of earthquakes. Map courtesy of Portland State University There, researchers monitored the treatment performance and [...]

Earthquake in Haiti Triggers Landslides

Source: Hundreds of landslides followed Haiti earthquake, Tropical Depression Grace - The Washington Post Source: Earthquake in Haiti Triggers Landslides After a 7.2 magnitude earthquake hit southwestern Haiti on the Saturday morning of August 14th, hundreds of landslides threatened the area. Landslides are one of the biggest causes of earthquake-related deaths. In 2010, the earthquake near Haiti's capital, Port-au-Prince, killed roughly 200,000 people and led to tens of thousands of landslides. The earthquake was centered about eight miles southeast of Petit-Trou-de-Nippes at a depth of six miles. USGS reported at least 150 landslides south of the epicenter, to the west of the town L'Asile. The mountains and south of Beaumont experienced hundreds more. “Even though a lot of the central and western parts of the epicentral area have been obscured by cloud cover, we haven’t seen too many landslides in the gaps in the clouds,” wrote Robert Emberson, a landslide researcher at NASA’s Goddard Space Flight Center. “We anticipate that the bulk of the landsliding (at least from the earthquake) is in the [Pic Macaya] National Park.” The National Hurricane Center predicted 5 to 10 inches of rain in Haiti with a possibility of up to 15 inches. Flash flooding, mudslides, and landslides were all expected following the rain. “With the ongoing tropical storm rainfall, further landslides are likely,” wrote Emberson. “In particular, landslide material mobilized by the earthquake may be washed downstream as debris flows. We will continue to monitor changes over the coming days to assess the exacerbated impact of the rainfall and provide situational awareness.” Landslides and earthquakes have recently in multiple parts of the world. Denali Park, Sichuan China, Battle Creek Michigan, and a recent Monsoon in India are just four of the most recently affected areas.

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