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.
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
LAS VEGAS (KSNV) — A string of deadly crashes in and around Pahrump has prompted Nye County Sheriff Joe McGill to push for more safety measures along dark, sidewalk-free roads.
“The worst penalty is death, if you consider that,” McGill said.
The recent deaths include a single-vehicle rollover on State Route 160 during the morning hours of the last Wednesday in January that killed one person and injured another.
Then, into February, two pedestrians were killed in less than three days.
The first was a 7 p.m. crash on Quarter Horse Avenue. Investigators believe a 2006 Jeep Liberty was driving on the street when it hit a pedestrian, who was pronounced dead at the scene.
A few days later, this last Saturday, state troopers responded to a crash just after sundown at Charleston Park Avenue. A sedan hit a pedestrian, who was also pronounced dead at the scene.
Nevada State Police investigators are still investigating both pedestrian cases before more details are released.
McGill said the recent crashes were enough to spur action.
“When the third one came out, I was sitting at home and watching TV. I looked at my wife and I said, ‘We got to do something about this,’” McGill said.
McGill is responding with a reflective vest giveaway, pointing to limited infrastructure as a possible factor. He noted a lack of street lights off State Route 160 and no sidewalks inside the community.
“The only light that you have is the ambient light from houses and cars so it is really dark,” McGill said.
John Treanor of AAA Nevada said poor visibility can quickly turn dangerous for both drivers and pedestrians.
“It is very easy to be confronted with a situation that you cannot see coming because the visibility might be bad,” Treanor said.
Treanor encouraged pedestrians to carry lights and drivers to be prepared if they end up outside their vehicles in dark conditions.
“Having lights on you. Even carrying a flashlight allows something where a driver can see it,” Treanor said. “If you are a driver, make sure you have the right stuff in your car, in case you do get in a situation where you are on the side of the road and now you are in dark. Make sure you have a kit with some reflectors, some lights. Anything the trunk of your car in case you need it.”
McGill said vigilance is important even in daylight.
“Any time of the day, you have got to be vigilant. You have to keep aware of your surroundings if you are a walker or on a bicycle or if you are the driver,” he said.
Authorities also urged caution as more people may pull off roads in rocky areas along the route toward Death Valley National Park during springtime blooms, increasing the need for drivers and pedestrians to stay alert.
A waterfront mansion on the Nevada side of Lake Tahoe just sold for $46 million, less than three weeks after hitting the market.
The speedy deal marks a departure from the typical U.S. market.
Nationwide, homes took a median 78 days to land a buyer in January, five more than the same time last year and the 22nd straight month of homes taking longer to sell on a year-over-year basis, according to data from Realtor.com.
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The lavish log cabin-like residence, in Incline Village, listed on Jan. 24 for $47.5 million. It sold 20 days later, on Feb. 13, listing records show.
The more than 7,000-square-foot residence was built in 2014, and has double-height living spaces, walls of windows, beamed ceilings, fireplaces, and plenty of rustic exposed stone and wood, listing images show.
There’s also a gym, a wet bar, a spa, a wine room, an office, two separate game rooms, seven bedrooms and dramatic Lake Tahoe views. Outside, there’s a private sandy beach, multiple decks, a heated driveway and two exterior fireplaces, according to listing information.
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The seller and the buyer are both limited liability companies, according to property records. Both parties were represented by Jeff Brown of Tahoe Mountain Realty, who declined to comment on the deal.
The median home price in Incline Village was $1.595 million as of December, a fall of 3.3% from a year earlier, according to data from Realtor.com. Listings, meanwhile, spent an average of 130 days on the market.
Updated February 26, 2026 – 8:28 pm
click to expand photos
Green Valley’s softball team claimed an 8-6 win at Liberty on Thursday on the first day of high school spring sports competition in Nevada.
Green Valley next hosts Silverado at 3 p.m. Friday. Liberty plays at Bishop Gorman at 3 p.m. Friday.
Contact Alex Wright at awright@reviewjournal.com. Follow @AlexWright1028 on X.
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