Smaller, more frequent quakes help to reduce tectonic strain
Newswise — Woods Hole, MA — The San Andreas Fault in California is renowned for its large and infrequent earthquakes. However, some segments of the San Andreas Fault (SAF) instead are characterized by frequent quakes of small to moderate magnitude and high rates of continuous or episodic aseismic creep. With tectonic strain released in a quasi-steady motion, that reduces the potential for large earthquakes along those segments.
Now, researchers say ubiquitous evidence for ongoing geological carbon sequestration in mantle rocks in the creeping sections of the SAF is one underlying cause of aseismic creep along a roughly 150 kilometer-long SAF segment between San Juan Bautista and Parkfield, California, and along several other fault segments.
“Although there is no consensus regarding the underlying cause of aseismic creep, aqueous fluids and mechanically weak minerals appear to play a central role,” researchers say in a new paper, “Carbonation of serpentinite in creeping faults of California,” published in Geophysical Research Letters.
The new study integrates field observations and thermodynamic modeling “to examine possible relationships between the occurrence of serpentinite, silica-carbonate rock, and CO2-rich aqueous fluids in creeping faults of California,” the paper states. “Our models predict that carbonation of serpentinite leads to the formation of talc and magnesite, followed by silica-carbonate rock. While abundant exposures of silica-carbonate rock indicate complete carbonation, serpentinite hosted CO2-rich spring fluids are strongly supersaturated with talc at elevated temperatures. Hence, carbonation of serpentinite is likely ongoing in parts of the San Andres Fault system and operates in conjunction with other modes of talc formation that may further enhance the potential for aseismic creep, thereby limiting the potential for large earthquakes.”
The paper indicates that because wet talc is a mechanically weak mineral, “its formation through carbonation promotes tectonic movements without large earthquakes.”
The researchers recognized several possible underlying mechanisms causing aseismic creep in the SAF, and they also noted that because the rates of aseismic creep are significantly higher in some parts of the SAF system, an additional or different mechanism – the carbonation of serpentinite – is needed to account for the full extent of the creep.
With fluids basically everywhere along the SAF, but with only certain portions of the fault being lubricated, researchers considered that a rock could be responsible for the lubrication. Some earlier studies had suggested that the lubricant could be talc, a soft and slippery component that is commonly used in baby powder. A well-established mechanism for forming talc is by adding silica to mantle rocks. However, the researchers here focused on another talc-forming mechanism: adding CO2 to mantle rocks to form soapstone.
“The addition of CO2 to mantle rocks – which is the mineral carbonation or carbon sequestration process – had not previously been investigated in the context of earthquake formation or the natural prevention of earthquakes. Using basic geological constraints, our study showed where these carbonate-altered mantle rocks are and where there are springs along the fault line in California that are enriched in CO2. It turned out that when you plot the occurrence and distribution of these rock types and the occurrence of CO2-rich springs in California, they all line up along the San Andreas Fault in creeping sections of the fault where you don’t have major earthquakes,” said Frieder Klein, lead author of the journal article.
Klein, an associate scientist in the Marine Chemistry and Geochemistry Department at the Woods Hole Oceanographic Institution, explained that carbonation is basically the uptake of CO2 by a rock. Klein noted that he had used existing U.S. Geological Survey databases and Google Earth to plot the locations of carbonate-altered rocks and CO2-rich springs.
“The geological evidence suggests that this mineral carbonation process is taking place and that talc is an intermediary reaction product of that process,” Klein said. Although researchers did not find soapstone on mantle rock outcrops, results from theoretical models “strongly suggest that carbonation is an ongoing process and that soapstone indeed could form in the SAF at depth,” the paper notes.
These theoretical models “suggest that carbon sequestration with the SAF is taking place today and that the process is actively helping to lubricate the fault and minimize strong earthquakes in the creeping portions of the SAF,” Klein said.
The paper also notes that this mechanism may also be present in other fault systems. “Because CO2-rich aqueous fluids and ultramafic rocks are particularly common in young orogenic belts and subduction zones, the formation of talc via mineral carbonation may play a critical role in controlling the seismic behavior of major tectonic faults around the world.”
“Our study allows us to better understand the fundamental processes that are taking place within fault zones where these ingredients are present, and allows us to better understand the seismic behavior of these faults, some of which are in densely populated areas and some of which are in lightly populated or oceanic settings,” Klein said.
This work was supported by grants from the National Science Foundation.
Authors: Frieder Klein1*, David L. Goldsby2, Jian Lin1, Muriel Andreani3
1Woods Hole Oceanographic Institution, Woods Hole, Massachusetts, USA
2University of Pennsylvania, Department of Earth and Environmental Sciences, Philadelphia, PA, USA
3Laboratoire de Géologie de Lyon, UMR 5276, ENS et Université Lyon 1, 69622 Villeurbanne Cedex, France
NASA Leaders to Highlight 25th Anniversary of Space Station with Crew
NASA is celebrating the 25th anniversary of International Space Station operations during a live conversation with crew aboard the microgravity laboratory for the benefit of humanity. During a space-to-Earth call at 12:25 p.m. EST Wednesday, Dec. 6, the Expedition 70 crew will speak with NASA Associate Administrator Bob Cabana and Joel Montalbano, space station program manager.
Watch on the NASA+ streaming service at no cost on demand. The discussion also will air live on NASA Television, the NASA app, YouTube, and the agency’s website. Learn how to stream NASA TV through a variety of platforms including social media.
On Dec. 6, 1998, the first two elements of the orbital outpost, Unity and Zarya, were attached by crew members of space shuttle Endeavour’s STS-88 mission. Cabana was the commander of the mission and the first American to enter the space station.
Through this global endeavor, astronauts have continuously lived and worked aboard the space station for more than 23 years, testing technologies, performing science, and developing the skills needed to explore farther from Earth. It has been visited by 273 people from 21 countries.
More than 3,300 research and educational investigations have been conducted on station from 108 countries and areas. Many of these research and technology investigations benefit people on Earth, and many lay the groundwork for future commercial destinations in low Earth orbit and exploration farther into the solar system. Together with Artemis missions to the Moon, these proving grounds will help prepare NASA for future human exploration of Mars.
Learn more about the International Space Station at:
NASA, Partners Launch US Greenhouse Gas Center to Share Climate Data
NASA Administrator Bill Nelson, U.S. Environmental Protection Agency (EPA) Administrator Michael Regan, and other United States government leaders unveiled the U.S. Greenhouse Gas Center Monday during the 28th annual United Nations Climate Conference (COP28).
“NASA data is essential to making the changes needed on the ground to protect our climate. The U.S. Greenhouse Gas Center is another way the Biden-Harris Administration is working to make critical data available to more people – from scientists running data analyses, to government officials making decisions on climate policy, to members of the public who want to understand how climate change will affect them,” said Nelson. “We’re bringing space to Earth to benefit communities across the country.”
The U.S. Greenhouse Gas Center will serve as a hub for collaboration between agencies across the U.S. government as well as non-profit and private sector partners. Data, information, and computer models from observations from the International Space Station, various satellite and airborne missions, and ground stations are available online.
As the lead implementing agency of the center, NASA partnered with the EPA, National Institute of Standards and Technology, and National Oceanic and Atmospheric Administration. Science experts from each of these U.S. federal agencies curated this catalog of greenhouse gas datasets and analysis tools.
“A goal of the U.S. Greenhouse Gas Center is to accelerate the collaborative use of Earth science data,” said Argyro Kavvada, center program manager at NASA Headquarters in Washington. “We’re working to get the right data into the hands of people who can use it to manage and track greenhouse gas emissions.”
The center’s data catalog includes a curated collection of data sets that provide insights into greenhouse gas sources, sinks, emissions, and fluxes. Initial information in the center website is focused on three areas:
- Estimates of greenhouse gas emissions from human activities
- Naturally occurring greenhouse gas sources and sinks on land and in the ocean.
- Large methane emission event identification and quantification, leveraging aircraft and space-based data
An example of a dataset is the methane gas information detected by NASA’s EMIT (Earth Surface Mineral Dust Source Investigation) mission. Located on the International Space Station, EMIT is an imaging spectrometer that measures light in visible and infrared wavelengths and thus can measure release of methane on Earth.
Built on open-source principles, the U.S. Greenhouse Gas Center’s datasets, related algorithms, and supporting code are fully open sourced. This allows anyone to test the data, algorithms, and results. The center also includes user support and an analysis hub for users to perform advanced data analysis with computational resources and an interactive, visual interface for storytelling. NASA encourages feedback and ideas on the center’s evolution. The center is part of a broader administration effort to enhance greenhouse gas information, outlined in the recently released National Strategy to Advance an Integrated U.S. Greenhouse Gas Measurement, Monitoring, and Information System.
For more information on NASA, visit:
Boom Partners with Latecoere for Supersonic Aircraft EWIS Architecture
Boom teams up with Latecoere to redefine EWIS architecture for supersonic aircraft, bringing together expertise for optimal safety and reliability.
Boom, the innovative aerospace company, has announced its collaboration with global aerospace leader Latecoere as part of its expanding network of suppliers. Latecoere’s engineering team in Toulouse, France, will work in conjunction with Boom engineers to define the complete electrical wiring interconnection system (EWIS) architecture for both Overture and Symphony aircraft.
Latecoere’s expertise in developing and manufacturing certifiable EWIS and advanced aircraft technologies makes them a valuable addition to Boom’s lineup of suppliers for Overture. The EWIS for these aircraft will consist of an extensive 103 kilometers (64 miles) of wiring, encompassing over 45,000 electrical connections. This comprehensive system ensures optimal safety and reliability for Overture and Symphony.
Latecoere brings years of experience in complex aircraft development processes and methods, making them an ideal partner for Boom. The company’s industry-leading harness architecture definition software stack will be leveraged to support Boom’s ambitious goals in sustainable supersonic air travel.
By collaborating with top-tier suppliers like Latecoere, Boom is demonstrating its commitment to assembling a world-class team to make supersonic air travel a reality. Latecoere’s CEO, Greg Huttner, expressed pride in supporting Boom’s vision and continuing to contribute to the development of next-generation flight. This partnership is a significant step forward in the advancement of supersonic aviation technology.
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