Welcome to the Cal Geographic Report for February 2026 – We look forward to sharing news and updates of the biogeography and geomorphology of California’s living landscapes.
Topics on this episode include regional volcanos, earthquakes, rare plants, the elusive Sierra-Nevada Red fox, Saharan cyanobacteria, abyssal turbidites, and more!
We will cover updates from the US Geological Survey, the California Geological Survey, the California Department of Fish and Wildlife, the US Fish and Wildlife Service, and select studies by researchers investigating California’s physical geography and biogeography.
Links and citations to the topics covered in this episode can be found on our website, Cal Geographic.com, on the transcript of this episode of the Cal Geographic Report.. Thanks for tuning in!
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Let’s start with up to date earthquake activity and volcano status for the state of California from the USGS calvo website:
All volcanos monitored by the USGS California Volcano Observatory are at the Normal Alert level today. From north to south these volcanos and volcanic regions include:
Cascades subduction complex volcanics:
Medicine Lake Volcano
Mount Shasta
Lassen Volcanic Center
Mendocino Triple Junction slab window/Mendocino Crustal Conveyor complex:
Clear Lake Volcanic Field
Basin and Range extensional tectonic complex:
Mono Lake Volcanic Field
Mono-Inyo Volcanic Crators
Long Valley Caldera
Mammoth Mountain
Ubehebe Crators
Coso Volcanic Field
Southern San Andreas Fault tectonic and transtensional complex:
Salton Buttes
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Let’s look at the most recent earthquakes in California over the magnitude of 2.0, within the last two weeks:
We will not list all recent earthquakes in the state, as there are many, but we will take a look at broad geographic and tectonic patterns:
So first, a small cluster of earthquakes has occurred approximately 20-30 km NNW of Alder Springs, in the rugged and remote Mendocino National Forest. The largest of these was a 3.3 magnitude on February 10th. They appear to be northeast of the Etsel Ridge Fault, which is part of the Bartlett Springs Fault system, but not on it. Possibly on or near the Coast Range thrust which separates the eastern belt of the north Coast Range and the Great Valley sequence.
Another 3.3 mag quake occurred on February 11th, 9 km WNW of Petrolia, along the always seismically active Mendocino Triple Junction and southern Cascadia subduction zone, which is home to multiple faults, including the Mendocino Fracture Zone, the San Andreas, and numerous faults on the subducting Gorda Plate.
There have been a lot of small earthquakes in the past two weeks along the San Andreas Fault from Hollister in the north, down to about Parkfield in the south. There is an ongoing cluster along the eastern border of Pinnacles National Monument. And the largest magnitude looks like a 3.1 on February 11th southwest of Hollister in a cluster going on within the Hollister Hills State Rec area, which is in the Diablo or Gabilan Range.
I’m always interested in and stoked by seismicity along the Maacama rift zone. And in the last two weeks there have been several small earthquakes, mostly under 2.5 in magnitude, along the Maacama ranging from a couple between Healdsburg and Cloverdale in the south, up to east of Willits and Laytonville, and one up at the north end of the Maacama fault zone near Redway in Humboldt County.
There is a cluster of earthquakes occurring in the heart of the Maacama rift right at Redwood Valley, near the intersection of 101 and East Highway 20. These are ranging from 1.4 to 2.5 in magnitude and have been ongoing since February 7th. We just go our new wonderful rescue dog from the Humane Society of Inland Mendocino which is sitting right on this current cluster of earthquakes!
The Maacama fracture zone lies at the border of the Pioneer Fragment and the Mendocino Triple Junction Slab Window, forming what is believed to be a deep shear zone and the primary plate boundary between the Pacific and North American plates in northern California.
And of course just a brief mention of the swarm of earthquakes under magnitude five that have been ongoing in the San Ramon area. This seismic activity is occurring on the Calaveras Fault system, pretty much between the Pleasanton and Calaveras Faults, and is a region that has experienced earthquake swarm cycles repeatedly over time. This swarm has been ongoing for a few months, since November of 2025, is in a densely populated region of the East Bay Area, and has been covered significantly by the media.
On our last podcast episode I covered some basic info on earthquake behavior. Here is a link to our complete post on Basic Earthquake Behavior.
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In other recent geomorphology and tectonics news for California, we are highlighting the following three studies:
From California’s north coast and the southern Cascadia subduction zone, the study, Widespread abyssal turbidites record megathrust earthquake-triggered landslides and coseismic deformation in the Cascadia subduction zone, byJenna C. Hill, and authors illuminates:
Abyssal marine turbidites provide some of the longest and most spatially extensive records of subduction zone earthquake recurrence globally; however, correlation of these deposits over long distances and interpretation of synchronous emplacement requires both an understanding of the turbidite generating systems and precise dating. Here, we present an integrated suite of high-resolution bathymetry, subbottom profiles, and sediment cores from combined autonomous underwater vehicle, remotely operated vehicle, and ship-based studies at a key paleoseismic site in the southern Cascadia subduction zone. We demonstrate how widespread, earthquake-triggered landslides on the lower slope deposit discrete, proximal mass transport deposits (MTDs) that grade offshore into complex, interfingered abyssal turbidites, which correspond to records of megathrust earthquake history. We propose accretion and oversteepening of thrust folds on the lower slope both preconditions the slope to fail and provides a perpetual source of unstable material to fail during every earthquake cycle. Furthermore, we suggest the periodic and pervasive landsliding indicates coseismic deformation of the outer accretionary wedge during megathrust rupture.
Hill, J.C., et al. 2026. “Widespread abyssal turbidites record megathrust earthquake-triggered landslides and coseismic deformation in the Cascadia subduction zone.” Science Advances 1-18
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Another recent landslide study is from southern California’s Transverse Range. A LiDAR-Based Bedrock Landslide Inventory of the San Gabriel Mountains, California, by Terry Checkbun Li:
The San Gabriel Mountains (SGM) geologic mapping, susceptibility models, and tectonic investigations to better assess are one of the most tectonically active mountain ranges in the U.S., yet a comprehensive LiDAR-based landslide inventory (LSI) has not been completed at the range scale. This study presents a novel, high-resolution LSI of the SGM using 1 m LiDAR multi-hillshade imagery, mapping nearly 12,000 bedrock landslides and analyzing their relationships with geology, topography, tectonic blocks, and landslide susceptibility. Results show that crystalline rocks host the majority of large landslides, supporting prior hypotheses that stronger rocks can produce larger landslides. Landslides sourced in schist display disproportionately high abundance and distinctive morphology, with internally deformed, topography-mantling deposits that differ from more blocky, coherent failures in other lithologies. Fault-bounded structural blocks show varied landslide behavior, with notably high landslide density along the range-front area, suggesting possible reactivation of the San Gabriel Fault or complex deformation within the Sierra Madre and Tujunga blocks. A region of Tertiary volcanics stands out for its disproportionately high density of landslides. Findings made by this study underscore the need for further refinement of landslide hazards in active orogens such as the SGM.
Terry Checkbun Li, T.C. 2025. “A LiDAR-Based Bedrock Landslide Inventory of the San Gabriel Mountains, California” University of California Riverside
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And from two distinct and highly active tectonic regions of the San Andreas Fault in Southern California, the study, Memory and jamming in fault zone sediments, looks at the processes and geomorphology of sediments directly within fault zones of the Salton Trough and the Transverse Range:
Many subsurface processes involve transitions in granular material states, from arrested to creeping to flowing. Experiments and frameworks for idealized systems reveal that granular fabrics develop during shearing, co-evolve with applied stress, and govern such transitions. We use microtomography to test whether fabrics at two San Andreas fault sites reflect slip history and whether idealized frameworks extend to nature. These natural granular systems preserve a material memory that can be examined in three dimensions. This memory may help decipher the paleoseismic slip histories of faults that have produced ground-rupturing earthquakes and creep. Our analyses indicate that fault zone sediments likely experience cycles of shear induced material memory creation and erasure wherein aseismic slip produces a distinct fabric that can then be erased and replaced during coseismic slip. Our findings have implications for modeling rigidity loss, the earthquake energy budget, and rupture propagation within the shallow subsurface. Finally, our work demonstrates that the near surface shear stresses during ground-rupturing earthquakes and aseismic slip are sufficient to break grains away from the fault slip surface.
Jhardel Dasent, J., et al. 2025. “Memory and jamming in fault zone sediments.” Communications Earth & Environment 6:998
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Here is a sample of recent news and studies concerning California’s rich biodiversity, including plants, wildlife, and algae and lichens:
Hot off the press:
The California Fish and Game Commission (Commission) at its Feb. 11-12 meeting approved listing mountain lion populations in parts of southern California and the central coast as a threatened species under the California Endangered Species Act (CESA). The Commission determined that listing this population of mountain lion is warranted due to threats such as habitat loss, habitat fragmentation and isolation of small populations as a result of expanding human infrastructure, all threats reported in a status review of the species by the California Department of Fish and Wildlife.
The Commission’s decision reflects its statutory responsibility under CESA to rely on the best available scientific information and to evaluate whether a native species faces threats that place it at risk of extinction in a significant portion of its range. The Commission found that the southern and central coast mountain lion populations are demographically and genetically isolated, with limited natural connectivity to other populations, making them particularly vulnerable to cumulative impacts.
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This week the California Department of Fish and Wildlife recommended that the state’s wildlife commission review whether to protect two declining species of desert songbirds — Bendire’s thrasher and LeConte’s thrasher — under the California Endangered Species Act. Over the past 50 years the number of Bendire’s thrashers has declined by 90% and LeConte’s thrashers have dropped by nearly 70% throughout their U.S. range. Bendire’s thrasher and LeConte’s thrasher are native to arid lands of the southwestern United States and northwest Mexico.
About 5% of the global population of Bendire’s thrasher, an estimated 4,400 birds, lives in the Sonoran and Mojave deserts in southeastern California. An estimated 37,000 LeConte’s thrashers, more than 80% of the global population, inhabit the Sonoran Desert and Mojave Desert portions of California as well as the southern San Joaquin Valley.
Significant areas of suitable thrasher habitat in southeastern California deserts and the southern San Joaquin Valley have been lost to sprawl development and agriculture. Habitat fragmentation and other threats such as invasive species, altered wildfire regimes, climate change, livestock grazing, off-road vehicles and mining are pushing both thrasher species to the brink.
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Last week the California Department of Fish and Wildlife (CDFW) announced the First Capture and GPS Collar of a Sierra Nevada red fox (Vulpes vulpes necator) in the southern Sierra Nevada. Due to their rarity, Sierra Nevada red foxes in California are protected as a Threatened Species under the California Endangered Species Act. The population in the Sierra Nevada has additional federal protection, considered an Endangered Species under the federal Endangered Species Act.
The foxes in the Sierra Nevada are isolated from their relatives in the Cascade Range, and the movements and behavior of this collared fox will offer scientists a rare opportunity to better understand the ecology and conservation needs of this remote group. The Sierra Nevada population is estimated to be fewer than 50 individuals. The species is typically extremely wary of humans and inhabits barren, rugged terrain at high elevations.
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From Santa Barbara,Deciphering spatial scales of connectivity in a subsidy-dependent coastal ecosystem researchers looked at the connections between California’s nearshore and beach ecosystems. Kyle Emery, and authors explain:
Connectivity within and across ecosystems is a dynamic process that greatly influences populations, communities, food webs, and ecosystem functions. Material exchanges, primarily of organic and inorganic resources, are facilitated and controlled by the degree of ecosystem connectivity and have important implications for food web support and key ecosystem processes,including primary production and decomposition.
One of the largest observed cross-ecosystem subsidies occurs between kelp forests and sandy beaches. Detrital exports from kelp forests comprise a major component of their net primary production and provide trophic support to adjacent ecosystems with low in situ primary productivity. Once this drift kelp is cast ashore as wrack, it shapes the entire ecosystem from bottom-up stimulation of the food web to habitat provisioning and a myriad of other ecosystem functions.
These important linkages between kelp forests and beaches are under threat given the intensifying disruptions and climate forcing affecting both ecosystems Here, we explore the combined effects of wrack supply and spatial scale on kelp forest subsidies to the sandy beach and investigate how beach condition impacts this relationship. Our results show that connectivity between kelp forests and beaches is strongest at local scales, of less than 10 km, and is influenced by both kelp supply and beach condition.
Kyle A. Emery, K.A., et al. 2025. “Deciphering spatial scales of connectivity in a subsidy-dependent coastal ecosystem.” Communications Biology 8:949
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From,Sulcaria isidiifera: Status and conservation methods for a critically endangered lichen on the central coast of California, Eli Balderas and authors summarize:
The splitting yarn lichen (Sulcaria isidiifera) was listed as Critically Endangered on the International Union for Conservation of Nature Red List in 2019 due to its very narrow distribution, a continuing decline in both its extent of occurrence and number of mature individuals, severe population fragmentation, and threats from development and fire. Sulcaria isidiifera is also listed as Critically Imperiled and at high risk of extirpation in the California Natural Diversity Database. It is one of 18 lichens of conservation concern in California.
The entire population of S. isidiifera is restricted to a small area on the central coast of California in the vicinity of the Baywood Los Osos and Morro Bay communities. The population is reported to occur over an estimated area of approximately 8 km2 in and around several state and local protected lands including Los Osos Oaks State Reserve, Montaña de Oro State Park, Morro Bay State Park, Morro Dunes Ecological Reserve, and the El Moro Elfin Forest. In this study we sought to further characterize the population status and ecology of this rare and threatened lichen. Additionally, we sought to develop methods for conservation translocation of S. isidiifera and highlighted the need for conservation actions that should be undertaken to protect this lichen.
Given the diversity of lichens, their important role in ecosystems, and the lack of legal protections that exist there must be concerted efforts at both the regional and national level to protect these organisms.
Balderas, E., et al. 2023. “Sulcaria isidiifera: Status and conservation methods for a critically endangered lichen on the central coast of California.” Bulletin of the California Lichen Society 30:34-40
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Discovery of a new cyanobacteria in the Channel Islands reveals a possibility for California’s global biogeographic connections –Pseudoacaryochloris (Acaryochloridaceae, Cyanobacteria) Species from Africa and North America: A Disjunct Distribution Suggesting Transatlantic Wind Dispersal By Jeffrey Johansen, and authors, tell us:
Cyanobacteria are critical primary producers not only in the world’s aquatic environments but also in terrestrial environments, where their role in microbial food webs is just starting to be revealed. Two new species of Pseudoacaryochloris, a recently described coccoid cyanobacterial genus from hypolithic and endolithic aridland habitats in the Sahara desert, were found in temperate-climate terrestrial habitats in Ethiopia and on San Nicolas Island, California. The Ethiopian isolate showed closer genetic affinity with the San Nicolas Island strain than either did with the Saharan species.
The close genetic relationship of the San Nicolas Island species and the species found in Ethiopia, here described as P. cystiformans and P. abyssiniae, respectively, supports the hypothesis that dispersal of cyanobacterial species from arid soils in Africa has led to establishment of this genus in the Americas, followed by genetic lineage separation in the immigrant population(s). This dispersal and divergence has likely occurred due to infrequent extreme wind storms in Africa that bring dust particles to both the nearctic and neotropical Americas.
Johansen, JR, et al. 2025 “Pseudoacaryochloris (Acaryochloridaceae, Cyanobacteria) Species from Africa and North America: A Disjunct Distribution Suggesting Transatlantic Wind Dispersal.” Western North American Naturalist 85(2):193-204.
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In a recent conservation update for the Mendocino Coast chapter of the California Native Plant Society, ecologist Peter Baye reported:
A tiny colony of indigenous Beach Pea, Lathyrus japonicas, was identified on a remote private stretch of the Mendocino coast by an environmental scientist for Caltrans, and reported to the California Department of Fish and Wildlife. The discovery was met with initial skepticism from local botanists until the photos were forwarded.
Lathyrus japonicas grows on beaches in the Pacific NW, and has a circumboreal distribution in Europe, Asia, and North America, with its assumed southern limit in Humboldt County, California.. but now down to Mendocino County. This discovery is a reminder of how limited botanical survey sampling of the Mendocino coast has been to support conservation, especially on private land.
The Mendocino Coast chapter of the California Native Plant Society (Dorothy King Young chapter) will inquire about seed or clone collection for off-site conservation of this irreplaceable, unique, extirpation-risky, isolated population. Thanks to Caltrans, CDFW, and botanical networking, the first steps toward conservation may be ahead.
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Thank you for listening – You can find citations, links, and references for the topics covered in this episode of the Cal Geographic Report on our website – CalGeographic.com. We look forward to further explorations and investigations of the biogeography and geomorphology of California’s Living Landscapes
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