Monumental Questions - What is the Bartlett Springs Fault Zone?

Kristie Ehrhardt • January 12, 2024

Bartlett Springs Fault location (USGS)

Within the Berryessa Snow Mountain National Monument (BSMNM) boundaries lies the Bartlett Springs Fault zone. The Bartlett Springs Fault is part of a larger southeasterly trending fault system that also includes the Green Valley Fault and the Calaveras Fault. The Bartlett Springs Fault runs approximately 100 miles through Lake County beginning at the Round Valley Indian Reservation and then south ending east of Clear Lake after crossing Bartlett Springs Road.


The Bartlett Springs Fault was acknowledged decades ago but it was not determined to be regionally seismically significant until the 1980’s. Geologists have found that the Bartlett Springs Fault slips approximately a quarter of an inch a year compared to the much larger San Andreas Fault which is estimated to move approximately two full inches a year. Despite being a relatively small fault, the Bartlett Springs Fault is seismically active and over time geologists have followed a series of microearthquakes with epicenters along the fault line. A relatively strong 5.1 earthquake occurred along the fault as recently as 2016, the most significant quake in 50 years and was felt from the coast east into the Central Valley of northern California.


Most of California’s faults are part of a wide zone formed as the edges of the Pacific and the North American plates rub and slide against each other. The Bartlett Hot Springs which are located along the fault line and within BSMNM boundary are a result of this tectonic activity. Hot springs occur when rain or groundwater is heated by the Earth’s geothermic energy beneath the surface. The temperature of the heated water causes it to seep to the surface. The region around the fault line also has geologic outliers; areas of younger rock surrounded by older rock. An outlier forms when some of the surrounding older rock is eroded leaving a section or “island” of younger rock that is no longer contiguous with the remaining layer of younger rock. The geologic outliers in the Bartlett Hot Springs area contain marine invertebrate fossils that date back to the Cretaceous Period which began 145 million years ago as well as fossils from our current (Cenozoic) era. Landslides in the area also presumably created two tension-crack caves that support habitat for Townsend’s big-eared bat (Corynorhinus townsendii), a special-status species. The serpentine soils in the region are a result of long-past frequent seismic activity and support several endemic plant species including the Adobe lily (Fritillaria pluriflora).



-Kristie Ehrhardt (kehrhardt@tuleyome.org)

Tuleyome Land Conservation Program Manager

RECENT ARTICLES

September 11, 2025
For Immediate Release: September 11, 2025  Contact: Nate Lillge, 530-379-8697, nlillge@tuleyome.org Trump Attacks Public Lands, Again Trump Proposes to Eliminate Public Lands Protections through Executive Action Woodland, CA – Yesterday, the Administration furthered their attack on America's public lands by directing the elimination of the Public Lands Rule . This is another step in the Administration’s wholesale assault on our public lands in clear opposition to the will of the people. The Public Lands Rule protects our treasured, multi-use landscapes so they'll be there tomorrow. The Rule recognizes that conservation is a type of land use, along with grazing, timber production, energy development, and recreation. Built on decades of management experience and guided by science and data, the rule provides land managers with essential tools to maintain our public lands, ensure access and protect our resources while supporting the diverse ways that communities depend on public lands. "The Public Lands Rule improves the management of our public lands, empowering the Bureau of Land Management to focus management on the needs of the lands where they work," says Sandra Schubert, Tuleyome Executive Director. "Rescinding the Public Lands Rule will rip authority from local land managers to place it in the hands of D.C. bureaucrats whose main goal is to sell our public lands to the highest bidder. All this in opposition to the overwhelming support for our public lands and their protection." By removing the Public Lands Rule, the Administration is failing ranchers and rural communities. Decision after decision made by this Administration has focused on short-term profit, extraction, and selling public lands to private entities. Supporting rural communities, the backbone of our economy and food systems, means ensuring farmers and ranchers have healthy lands they can depend on. It means empowering local BLM managers who understand what their communities need to thrive and provide for the American people. Overused lands don't recover. Degraded grasslands can't support cattle. Clearcut forests take decades to regrow. Contaminated watersheds poison communities for generations. True support for rural communities means embracing the Public Lands Rule. That is exactly why the American people want and support the Public Lands Rule. The Rule has overwhelming support. When given the chance to comment on the Public Lands Rule, more than 150,000 Americans did – 92% in support. When ranchers, recreationists, and resource companies all depend on the same lands, we recognize that we must use them responsibly to ensure they stay productive for everyone. The choice is clear: Protect our public lands for current and future generations, or consume everything now and leave nothing behind. Without the Public Lands Rule, our cherished landscapes lose protection and one of our greatest treasures, our public lands, is at risk.
By Sandra Schubert September 11, 2025
On July 10, 2025, we gathered to celebrate the 10th Anniversary of Berryessa Snow Mountain National Monument with the people who worked to establish the Monument in 2015 and add Molok Luyuk to it in 2024. We gathered in Lake County. The event began at the Tallman Hotel with folks gathering, speakers, trivia, food, videos, celebration and music by the Rural Jazz Project. We had folks from throughout the region – the Bay Area to Chico, Ukiah to Sacramento…. We had our partners at the Bureau of Land Management, local government representatives and all aspects of our broad coalition – conservationists, scientists, hunters, hikers, and community members, and more. The presentations and speakers were amazing. Tuleyome put together a reel of Berryessa Snow Mountain National Monument highlights . I was privileged to emcee the event and welcome our speakers and guests. We were honored to have Tribal leadership. Michael Marcks, Vice Chairperson, Executive Council, Habematolel Pomo of Upper Lake graced us with opening prayer. Vice Chairman Michael Marcks was joined in providing remarks by Vice Chair Eddie Crandell, Vice Chairman for the Robinson Rancheria of Pomo Indians and Lake County Supervisor . Gail Totton, Tribal Resources Manager for the Yocha Dehe Wintun Nation , the lead for the addition of Molok Luyuk to the Monument, shared their thoughts on the anniversary and Molok Luyuk. U.S. Senator Alex Padilla spoke to us via video and emphasized the importance of our efforts and our public lands. Luca Moretti read a statement on behalf of Representative Mike Thompson , a legendary champion of public lands, who commended us all and provided Tuleyome with a Certificate of Special Congressional Recognition . We were surprised and flattered with the honor bestowed upon us. Representative Jared Huffman, Ranking Member of the U.S. House of Representatives Committee on Natural Resources , also spoke to us about his efforts to defend our public lands. Our state and local representatives also joined us. Rhiannon Philippi delivered remarks for California Senate President Pro Tempore Mike McGuire. California Senator Christopher Cabaldon spoke to us via video and Sergio Emmanuel Ildefonso Zarate on his staff celebrated with us. Assemblymember Cecilia Aguiar-Curry led a legislative resolution supporting the Monument, which was read by Laura Beltran . Many of our local Supervisors also celebrated with us. Brad Ramussen, Lake County Board of Supervisors , shared his insights. Lucas Frerichs, Yolo County Board of Supervisors , spoke to us and sponsored a Yolo County Board of Supervisor's resolution that was read by Bryan Pride, Tuleyome’s Policy Director . Neal Craig, BLM, Ukiah Field Office Manager , and our partners in protecting this amazing area, joined us and spoke to our collaboration. Interspersed with our speakers, Sara Husby, Tuleyome’s Executive Director when the Monument was established, led us in a series of trivia questions penned by Tuleyome’s own Kristie Ehrhardt. The depth of knowledge of our coalition shone through. And, it was fun. We hope folks enjoyed the prizes. Closing out the event were leaders in the conservation movement. José Gonzalez, founder and emeritus Executive Director of Latino Outdoors , offered his insights on the importance of public lands to all of our communities. Bob Schneider and Andrew Fulks , Tuleyome Co-founders and Tuleyome Advisory Council Members, shared the history of the movement and some stories, bringing us full circle, from the time when the idea of a Monument was a spark in their eyes to the establishment and expansion of the Monument. After the event at the Tallman, many of us headed to Middle Creek Campground, a few miles away for some nighttime fun. There was a nature walk with botany, forest bathing, star gazing, owling, s’mores, camping and laughter. I learned new ways of making s’mores, including a toasted marshmallow with a mini peanut butter cup tucked inside. Delicious! And, as a reminder of how wonderful our coalition is, there was an animal rescue. The morning after the event, many of us went to Judy’s Junction in Upper lake for breakfast. When I arrived with my mom, who had joined us, we saw numerous people under the hood of Jora’s car – Nick, Brendan, Karah, Isobel, Jora and a pair of legs sticking out from under the vehicle that I did not recognize. They were searching for a kitty that had lodged itself in Jora’s engine area. After much hullabaloo, the kitty ran – fast. We all thought – no, not over the highway! But, the little scamp jumped into another newly parked car engine. The chivalrous owner opened his hood and let us at it. I didn’t do much. I offered my shirt as a barrier to the hot engine. The heroes were the others. Folks from inside the diner pitched in, but it was our coalition to the rescue – the folks above and then Kim showed up. I’m not sure how, after all the time and efforts, but she was finally able to reach in and rescue the kitty. I saw her pull the little ebony guy out, hug him and rub her face against his. And I knew – he was no longer abandoned; he had a forever home. And, I was right, the little guy is now living with Kim and her family. I didn’t need the confirmation, but watching our group spend a couple of hours rescuing that little creature reminded me why I love this community. We care – all of us – about the life, the place and the creatures we live with. All of them. Big and small. None of this would have been possible without our generous sponsors: CalWild, Conservation Lands Foundation, Defenders of Wildlife, Sierra Club National, Sierra Club Redwood Chapter, Tallman Hotel and Tuleyome. Thank you so much for your continuing support of Berryessa Snow Mountain National Monument and all of our public lands. And thanks to all of you – everyone at the celebration, those who could not join us, and the kitty rescue team. You are what community is. I am honored to be part of ours. -Sandra Schubert Executive Director
By Nate Lillge September 11, 2025
Tuleyome is excited to welcome Mary Lamborn as our Communications Intern. She will working closely with Tuleyome staff to increase Tuleyome's outreach and positive impact on public lands in the northern Inner Coast Range Mountains and western Sacramento Valley. Mary is a recent graduate of UC Davis with a B.S. in Environmental Policy Analysis and Planning. As a native of the northern Inner Coast Range, she has deep ties to the region and spent time on the trails and waterways in Berryessa Snow Mountain National Monument. Welcome, Mary!