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Deep Beneath California’s Sierra Nevada, Earth’s Lithosphere May Be Peeling Away – Eos

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Deep Beneath California’s Sierra Nevada, Earth’s Lithosphere May Be Peeling Away – Eos


Source: Geophysical Research Letters

The processes that form continental crust from the denser basaltic rocks of the upper mantle may make the lower lithosphere denser than the underlying mantle. One theory holds that the lower lithosphere splits away and sinks into the mantle in a process called foundering. Conclusive evidence of foundering, however, has been hard to come by.

Peering deep under California’s Sierra Nevada, Schulte-Pelkum and Kilb discovered new evidence of lithospheric foundering in progress. The team imaged the lower crust and uppermost mantle beneath the Sierra Nevada with receiver function analysis, which uses seismic waves that change as they cross structures beneath the surface.

They also studied earthquake data from the Advanced National Seismic System Comprehensive Earthquake Catalog, or ComCat. They found a band of seismicity in the central Sierra, in which small earthquakes (ranging from magnitude 1.9 to 3.2) occur at the unusual depths of 40 kilometers and greater.

Differences in receiver functions along the mountain range revealed a distinct layer in the mantle, which grows gradually less distinct farther north. This aligns with the existing hypothesis that a section of the lithosphere beneath the southern Sierra sank (foundered) millions of years ago.

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A slab of colder continental lithosphere also has the capacity to crack, rather than to stretch and flow like hot material typically found at such depths. This likely also explains the presence of such deep earthquakes in the central Sierra, according to the authors.

The researchers found no evidence of this layer in the northern Sierra, indicating foundering has yet to progress to that region.

This work aligns with previous studies that found a gradient Moho, rather than a sharply defined crust-mantle boundary, under the Sierra. It also matches previous suggestions that a cold mantle anomaly under the Great Valley region to the west may be dense lithosphere lost to the foundering process. Foundering has been ongoing in the Sierra for at least 3 million years according to this hypothesis, and the researchers say it may be progressing northward. This region provides evidence of a process of differentiation that occurs throughout Earth’s crust, they argue. (Geophysical Research Letters, https://doi.org/10.1029/2024GL111290, 2024)

—Nathaniel Scharping (@nathanielscharp), Science Writer

Citation: Scharping, N. (2025), Deep beneath California’s Sierra Nevada, Earth’s lithosphere may be peeling away, Eos, 106, https://doi.org/10.1029/2025EO250020. Published on 17 January 2025.
Text © 2025. AGU. CC BY-NC-ND 3.0
Except where otherwise noted, images are subject to copyright. Any reuse without express permission from the copyright owner is prohibited.
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Cold Front Brings Strong Wind, Cooler Temperatures to Las Vegas

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Cold Front Brings Strong Wind, Cooler Temperatures to Las Vegas


LAS VEGAS (FOX5) — A cold front moving into Southern Nevada will bring strong wind, cooler temperatures and several days of unsettled weather.

Thursday and Friday are First Alert Weather Days, with the strongest wind expected late Thursday night into early Friday morning. A Wind Advisory will go into effect at 11 am Thursday through 5 am Friday.

EN ESPAÑOL: Un frente frío trae vientos fuertes y temperaturas más frescas al sur de Nevada

On Thursday, southwesterly wind will increase throughout the day, before shifting out of the north. Gusts will reach 30 to 40 mph across most areas, with higher gusts in elevated terrain. The high in Las Vegas will reach 82° Thursday.

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The strongest wind will follow the front, with northerly wind strengthening late Thursday into Friday morning.

The front will also bring cooler air into the region, dropping temperatures from top to bottom on Friday. The high will drop to 69°, with the wind backing off to more of a breeze by Friday afternoon.

Conditions will improve over the weekend as high pressure builds. Highs will reach 78° Saturday and 86° Sunday with lighter wind.

Another system arrives early next week. Monday and Tuesday are also First Alert Weather Days, with highs of 87° and 80°, bringing renewed wind and a slight chance of showers by midweek.

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Catholic Charities of Southern Nevada marks 85 years, now serving 4,500 daily

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Catholic Charities of Southern Nevada marks 85 years, now serving 4,500 daily


Catholic Charities of Southern Nevada is marking 85 years of service on April 16th, a milestone that leaders say reflects both the organization’s growth and the region’s ongoing needs.

The nonprofit says it traces its early roots to Northern Nevada and later expanded into Southern Nevada to help people after the building of the Hoover Dam. Historical photos from the organization show its footprint widening over the decades as Las Vegas grew.

Today, Catholic Charities of Southern Nevada operates 16 programs and serves about 4,500 individuals every day, according to President and CEO Sara Ramirez, who adds the organization’s work is driven by three core values: families, food, and housing.

“No one promised us an easy life. If you have a solid family base around or support system around you, you’re more likely to overcome the crisis and not only overcome but overcome it quickly back to a state of normalcy,” Ramirez said.

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On food security, Ramirez said, “Food is life and that is imperative regardless of whether your are a newborn child or a senior in our Meals on Wheels program.”

For housing stability, Ramirez noted the 400-bed men’s shelter and the St. Vincent Apartments, a 120-unit apartment complex on the Catholic Charities campus that provides a place to stay for people who are unhoused or facing housing instability.

The anniversary comes as Clark County awaits results from the annual point-in-time count, a census of people living without a permanent home that took place in January. The last census found nearly 8,000 people experiencing homelessness on a single night.

While the official count is still being tallied, Nicole Anderson, vice president of social services, described what she witnessed during the count.

“To go out in the community at 4, 5 in the morning, and intentionally look for people and see the areas they’re sleeping in; to see a young woman, under a blanket in a corner because that’s the only place she can stay warm, it’s heartbreaking,” Anderson said.

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Anderson spoke with us in a classroom. “Clients work off these computers,” she said, describing the space where people can learn — or in some cases re-learn — employment skills, including how to interview, as they work to regain stability.

“They have to be ready, seeing them, make those changes and be confident again, and lean on these case managers and on each other, there’s a cool thing that happens naturally and organically,” Anderson said.

Ramirez also described what she called a growing trend of older people experiencing homelessness and shared what a daily meal can mean for someone struggling. “He had shared, Sara, my life is hard but for one hour every day, I can come to the dining hall, find a meal and find peace,” Ramirez said.



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Enrollment period almost over for Nevada’s prepaid tuition program

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Enrollment period almost over for Nevada’s prepaid tuition program


The enrollment period for the Nevada prepaid tuition program is almost over.

Wednesday, April 15, is the final day to create an account for the current enrollment period.

It’s a chance for parents to jumpstart their children’s education by starting to save now.

Nevada State Treasurer Zach Conine joined us to talk more about how you can lock in future tuition at today’s rates.

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