Science
Geological Carbon Sequestration in Mantle Rocks Prevents Large Earthquakes in Parts of the San Andreas Fault
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
Affiliations:
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
*corresponding author
News
Asteroid Apophis: An Exciting Encounter with Earth
Get ready for an exciting and safe encounter with asteroid Apophis as it zooms past Earth in 2029! Don’t miss this celestial event! #Apophis2029
In just five years, on April 13, 2029, the world will witness the close encounter of a rather infamous asteroid named Apophis. This grand event, visible to the naked eye, has sparked curiosity among astronomers and captured the attention of the public. However, rest assured, there is no reason for alarm. Let’s delve into the fascinating story of the asteroid Apophis and shed light on its journey through the cosmos.
Location, Location, Location:
Apophis is an asteroid measuring about 1,100 feet (340 meters) in diameter. Extensive calculations have revealed that it will safely pass by Earth both in 2029 and 2036. During the 2029 flyby, Apophis will come within a nominal distance of 19,662 miles (31,643 km) from our planet’s surface, closer than the moon and many satellites in Earth’s orbit. As it traverses through Earth’s gravitational field, the passage of Apophis might even cause subtle asteroid-quakes and slightly alter its orbit.
Spectacular Viewing Opportunities:
Although not observable from everywhere, lucky viewers in Australia, southern Asia, southern Europe, and Africa will have a front-row seat to witness Apophis at its brightest in 2029. As the asteroid gradually moves away from Earth and dims, it will become visible in eastern South America. Furthermore, as evening falls along the east coast of North America, telescopes will reveal Apophis located approximately 15 degrees north of the Pleiades. An ephemeris for the asteroid can be found on our website to help astronomers and enthusiasts track its celestial journey.
The Discovery of Apophis:
On the remarkable evening of June 19, 2004, astronomers at Kitt Peak National Observatory in Arizona made a thrilling discovery. Dave Tholen, Fabrizio Bernardi, and the late Roy Tucker stumbled upon an asteroid, later designated as 2004 MN4. What made this discovery even more extraordinary was the fact that the asteroid was unusually close to the sun, only 57 degrees away. Further observations revealed that Apophis had an orbit different from most asteroids, resembling that of an Aten-class asteroid.
Narrowing the Probability of Collision:
Initially, calculations showed that Apophis had a 2.7% chance of colliding with Earth on April 13, 2029, a date marked with superstition. This resulted in a media frenzy surrounding the potentially hazardous asteroid. However, over several years, astronomers meticulously observed Apophis, taking into account the influence of other celestial bodies and the Yarkovsky effect caused by sunlight. By 2006, these studies dispelled the notion of a collision in 2029, relieving the world of any imminent danger.
No More Worries for the Future:
Many eagerly awaited the subsequent close approach of Apophis in 2036. However, in 2013, after conducting radar observations using the Goldstone Deep Space Communications Complex and the Green Bank Observatory, NASA definitively ruled out any potential impact in 2036 and for the next 100 years. Apophis is now no longer on the Sentry Impact Risk Table, which lists potentially dangerous objects near Earth.
Unlocking the Scientific Opportunities:
With the new knowledge that Apophis poses no threat, astronomers can fully embrace the upcoming close encounter as a fantastic scientific opportunity. The OSIRIS-REx spacecraft, known for its historic mission to bring samples from asteroid Bennu back to Earth, is now en route to rendezvous with Apophis in April 2029. Renamed OSIRIS-APEX (Origins, Spectral Interpretation, Resource Identification, and Security – Apophis Explorer), this mission will unlock further insights into the asteroid’s composition and characteristics.
As we eagerly anticipate the visit of the asteroid Apophis in 2029, let us celebrate the wonders of our universe. Apophis serves as a reminder of the dynamic nature of our cosmic neighborhood and the continuously advancing knowledge of our exceptional astronomers. So mark your calendars and join the world in witnessing this extraordinary celestial event, which promises to be a captivating spectacle for all.
https://stmdailynews.com/category/science/
In a significant milestone for the nation’s first high-speed rail project, the California High-Speed Rail Authority (Authority) announced that it has successfully created over 13,000 construction jobs since 2015. This accomplishment not only signifies progress for the ambitious high-speed rail system but also highlights the positive impact it has had on the local Californian workforce.
Central Valley Takes the Lead:
With over 70 percent of these jobs going to residents of California’s Central Valley, the project has played a vital role in providing employment opportunities for individuals in the region. It is worth acknowledging the efforts of nearly 1,400 workers dispatched each day to various high-speed rail construction sites. These jobs have injected economic vitality and growth into communities across the Central Valley.
Regional Breakdown:
- Fresno County: 4,222 jobs
- Kern County: 2,538 jobs
- Tulare County: 1,282 jobs
- Madera County: 580 jobs
- Kings County: 462 jobs
- Merced County: 189 jobs
- Remaining California Counties: 3,387 jobs
- Out-of-State: 369 jobs
A Decade of Strong Partnerships:
The Authority has had a longstanding partnership with the California State Building Trades, which has facilitated the creation of thousands of good-paying union jobs. Notably, during the past five years alone, over 10,000 construction positions have been generated through these collaborative efforts. Moreover, a significant focus has been placed on directing employment opportunities towards individuals from disadvantaged communities, further promoting inclusivity and economic upliftment.
California Jobs First Council:
To bolster job creation even further and ensure economic prosperity for all Californians, the California Jobs First Council was established. This council aims to align economic resources, expedite job creation, and enhance opportunities throughout the state. With particular focus on the Central San Joaquin Valley, this initiative serves as an impetus for creating more jobs, rapidly, in every community.
Future Expansion and Construction Progress:
Looking ahead, the Authority is resolute in extending the current 119-mile high-speed rail network to span 171 miles, reaching from Merced to Bakersfield. The construction has already commenced on this expansion project. Presently, more than 25 dynamic construction sites are active within the Central Valley. As a testament to its commitment to environmental stewardship, the Authority has obtained full environmental clearance for 422 miles of the high-speed rail program, stretching from the Bay Area to Los Angeles County.
Stay Updated:
For the latest developments and information about the high-speed rail construction, interested individuals are encouraged to visit the official website: www.buildhsr.com. On the website, visitors can access recent videos, animations, photographs, press center resources, and the latest renderings of the project. All files are available for free use, courtesy of the California High-Speed Rail Authority.
The California High-Speed Rail Authority’s achievement of surpassing 13,000 construction jobs is undoubtedly a cause for celebration. By focusing on job creation and prioritizing the local workforce, this landmark project is making a positive difference in the lives of Californians, particularly those in the Central Valley. With continued progress and future expansions, the California High-Speed Rail project not only brings efficient transportation but also provides a substantial economic boost that benefits communities and individuals alike.
Source: California High-Speed Rail Authority
What is California High-Speed Rail?
The California High-Speed Rail (CAHSR) is a state-funded project led by the California High-Speed Rail Authority. Currently under construction, Phase 1 is planned to cover 494 miles from San Francisco to Los Angeles, passing through the Central Valley. There are plans for Phase 2, which would extend the system to Sacramento and San Diego, totaling 776 miles. Authorized by a 2008 ballot, this ambitious project aims to connect major urban areas, significantly reducing travel times. The goal for Phase 1 is to achieve a travel time of 2 hours and 40 minutes between San Francisco and Los Angeles, a vast improvement from the existing Amtrak service, which takes around nine hours.
Construction of Phase 1 began in the Central Valley back in 2015. The project is being built in sections due to limited funding. The state aims to complete a 171-mile (275 km) long Initial Operating Segment (IOS) connecting Merced and Bakersfield by 2024. The IOS is expected to begin its revenue service as a self-contained high-speed rail system between 2030-2033, at an estimated cost of $28–35 billion. CAHSR trains running along this section would be the fastest in the Americas, with a top speed of 220 mph (350 km/h).
Between January 2015 and December 2023, a whopping amount of $11.2 billion was spent on the IOS project, which includes 119 miles (192 km) currently under construction, alongside upgrades to the existing rail lines in the San Francisco Bay Area and Greater Los Angeles. The plan is that Phase 1 will share tracks with conventional passenger trains. However, the Authority has not yet secured funding to connect the Central Valley section with either the Bay Area or Los Angeles, which involves crossing several major mountain passes. As of 2024, it is estimated that Phase 1 will cost a total of $106.2 billion.n.
Supporters of the California High-Speed Rail project emphasize the potential benefits it offers, including the reduction of air traffic and highway congestion, decreased pollution and greenhouse gas emissions, and the promotion of economic growth by connecting inland regions to coastal cities. However, opponents argue that the project is too expensive and advocate for directing funds to other transportation or infrastructure initiatives. The choice of route and the decision to initiate construction in the Central Valley, rather than more densely populated areas, have been points of contention. The project has encountered notable challenges such as delays and cost overruns due to management issues, legal disputes, and a lack of complete funding commitment.
STM Blog
Riding the Rails to a Sustainable Future: The Rise of High-Speed Rail in the U.S.
High-speed rail in the U.S. offers a sustainable, faster, and comfortable alternative to flying and driving, significantly reducing carbon emissions.
In a world where environmental sustainability and efficient transportation are becoming increasingly critical, the United States is making strides towards a faster and greener future with the expansion of high-speed rail networks. While the U.S. may have lagged behind other countries in this area, promising developments such as the Brightline West project in the Southwest, the Texas line connecting major cities, and the Northwest corridor linking bustling urban centers are paving the way for a new era of travel.
High-speed rail presents a compelling alternative to traditional modes of transportation. With trains reaching speeds of up to 200 mph, these systems offer a comfortable, cost-effective, and time-efficient way to travel. Compared to flying, high-speed rail eliminates the hassles of airport security checks and long wait times, while surpassing the speed of driving without the stress of being behind the wheel. Passengers can unwind, be productive, or simply enjoy the journey, making it a holistic travel experience.
Beyond the convenience and comfort it offers, high-speed rail holds immense promise in reducing carbon emissions and combating climate change. The potential environmental impact of projects like the Brightline West is staggering, with estimates suggesting that millions of cars could be taken off the road, significantly curbing carbon pollution. Given the alarming statistics on the environmental cost of traditional transportation, transitioning to high-speed rail is a crucial step towards mitigating the harmful effects of climate change.
The urgency of addressing climate change cannot be overstated. The emissions released from burning fossil fuels are driving global warming at an alarming rate, leading to catastrophic consequences such as extreme weather events and environmental degradation. By opting for public transportation like high-speed rail, individuals can contribute to cooling down the planet and reducing their carbon footprint. Additionally, embracing sustainable modes of travel such as walking and biking not only promotes environmental conservation but also enhances personal health and well-being.
As the U.S. accelerates its efforts to embrace high-speed rail and other eco-friendly transportation options, we are moving closer to a future where sustainability and efficiency go hand in hand. By choosing to ride the rails, we are not only embarking on exciting journeys but also taking meaningful steps towards a cleaner, greener planet for generations to come.
If you are interested about high speed rail in America, check out these articles:
https://en.wikipedia.org/wiki/Acela
https://en.wikipedia.org/wiki/Brightline
https://en.wikipedia.org/wiki/High-speed_rail_in_the_United_States
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