#Geosphere

How do wildfire landscapes recover? And how does that change debris-flow risk over time? A new study in #Geosphere introduces an improved, satellite-based method for tracking how postfire debris-flow hazards evolve as vegetation regrows. By integrating multi-year burn recovery into the USGS “M1” hazard model, the authors show that debris-flow risk is not static—it decreases (and sometimes changes substantially) as burned landscapes recover. This recovery-aware approach improves rainfall threshold predictions and reduces false alarms, helping emergency managers better distinguish when a burned watershed is still dangerous versus when it has begun to stabilize. The method is already being incorporated into operational USGS hazard mapping workflows, improving guidance for postfire decision-making. This work is now also gaining broader attention, including coverage in EOS; read the paper: #WildfireRecovery #GeologicalHazards #HazardRisk

This week's most-read article for #Geosphere is the #OpenAccess article "Subduction zone megathrust earthquakes," by Susan L. Bilek & Thorne Lay. #Geology #Hazards #GSAPubs // Image: Fig. 14 from the paper; see image alt text for a description.

How and when did the Grand Canyon form? Geologists are still debating one of Earth’s most iconic landscapes. Research published in #Geosphere explores evidence that an ancient proto–Colorado River may have filled a vast basin in northern Arizona before spilling westward—potentially helping establish the modern course of the Colorado River through the Grand Canyon. This study argues against the spillover hypothesis based on evidence suggesting that the preserved lake deposits represent a shallow, playa-like lake rather than a deep, overflowing lake. Thus, this work supports a more gradual integration of the Colorado River system. However, new research published in Science and featured in Scientific American presents new evidence that supports both the spillover hypothesis as well as an older more gradual integration of the Colorado River system. This new study suggests that by around ~6.6 million years ago, an ancestral Colorado River was flowing into the northern Arizona basin, where a large lake (or lake system) likely formed and eventually spilled westward to establish the modern Colorado River pathway through the Grand Canyon. So, the debate is no longer “Did spillover happen at all?” but rather “How important was spillover relative to older canyon segments and gradual river integration?” Although further research is needed to answer this question, these studies add important insight into the long-running puzzle of when and how the Grand Canyon was carved. Read the Geosphere paper: #Geology #GrandCanyon

New #Geosphere research explores a provocative idea: that the Cascadia Subduction Zone and northern San Andreas Fault may not act entirely independently—but could partially influence each other through time. Using offshore sediment records spanning the past ~3,000 years, researchers identified evidence that some major earthquakes on these two fault systems may have occurred in closely linked sequences, raising new questions about stress transfer and earthquake synchronization along the U.S. West Coast. The study combines marine paleoseismology, turbidite stratigraphy, radiocarbon dating, and seismic records to investigate how these fault systems may interact near the Mendocino Triple Junction—one of the most tectonically complex regions on Earth. This work is gaining broader attention through coverage in outlets including KQED and the San Francisco Chronicle—read the paper: #Earthquakes #Seismology #Cascadia #SanAndreasFault

The first 2025 #Geosphere issue is now online and 100% #openaccess! Topics span from the Cretaceous magmatic arc of southwestern North America to gender, geoscience, and work-from-home initiatives. The issue includes a Queen Charlotte-Fairweather Fault System themed issue paper. February Geosphere cover image of the Lut Desert (southeastern Iran) is from NASA Earth Observatory.//Go to to have a better look at the cover and to view all articles. #GSAPubs #Geoscience #EarthScience

Which of these topics best match your interests and research? #BasinAndRange evolution won in our two polls. Good news: All three are #Geosphere themed issues open to submissions: Read about Basin and Range evolution: #GSAPubs

What if the mountains you see today slid 16 km from where they formed? New #Geosphere research uncovers that Utah’s east Traverse Mountains aren’t uplifted by faulting—they’re a massive late-Miocene mega-landslide (~75–150 km³!) that broke free from the Little Cottonwood stock. This discovery changes how we see mountain building and landslide hazards in extensional terrains. 🔗 Read more: #GSAPubs #UtahGeology #WasatchFront #StructuralGeology #Geoscience

New #Geosphere study! The origin of the Comoros Archipelago has been debated for 50 years. Research by Masquelet et al. links island formation to the East African Rift System. #Geology #Volcanoes #Comoros #EARS

New #Geosphere research on the Famatinian arc (NW Argentina) reveals two distinct magmatic stages—shaped by mantle-crust interactions and pre-existing lithosphere. Read more: #GSAPubs

The most-cited article for #Geosphere is #OpenAccess: "The lithospheric architecture of Africa: Seismic tomography, mantle petrology, and tectonic evolution" by G.C. Begg & colleagues #Geology #Africa Image: Map of the bedrock geology of Africa

New in #Geosphere: Richardson et al. examine new timing constraints for the timing of shearing in the Western Idaho Shear Zone. Read the full paper: Photo by Rex Parker, Wikimedia Commons. #GSAPubs #geoscience #ShearZones

New in #Geosphere: Hren and Brandon use new leaf wax hydrogen isotope data to show that the Sierra Nevada experienced renewed uplift in the late Cenozoic. #Geoscience #SierraNevada #Uplift #HydrogenIsotope

The April 2025 #Geosphere issue is now online and 100% #openaccess! Research spans the globe–from Oregon's Mount Hood to Southwest China–and features studies about such subjects as surface topographic changes from explosive experiments and the origin of big garnet amphibolites. Read the full issue here: #GSAPubs #Geoscience #EarthScience

The August 2025 #Geosphere issue celebrates 20 years—now live and 100% #OpenAccess! Explore research from 3 continents + a special intro from the editors on Geosphere’s past & future. Stay tuned for trivia next week: #GSAPubs #20YearsofGeosphere

Alamo Impact Crater: New Study Could Double Its Size #Geosphere

New #Geosphere Publication: 'Tracking the spatial and temporal links between late Cenozoic extension and magmatism in the Death Valley region (California, USA).' Chan et al.'s research presents high-precision U-Pb zircon ages, revealing three distinct phases of intrusive magmatism and their correlation with regional extension. Key findings highlight the plutonic record as a critical link to understanding tectonic changes. Read the full paper here: #GSAPubs #Magmatism #EarthScience #Geochronology

🌍 The June 2025 issue of #Geosphere is here—and it’s 100% #openaccess! Explore tectonics across North America, from the Sierra Nevada to the Basin and Range, plus stunning fossil reef imagery from west Texas. Read now: #GSAPubs #Geoscience

Volcanologists warn world is unprepared for next major eruption by @alexwitze via @NatureNews: Featured paper from #Geosphere:

Unveiling #SierraNevada uplift secrets! New research by Phillips in #Geosphere reveals coherent tilting history. Northern Sierra: rapid uplift 5-1.7 Ma. Southern Sierra: ongoing uplift since 12 Ma! #EarthScience Photo: Dylan Taylor, Unsplash

New research in #Geosphere presents the first systematic investigation of paleoearthquake timing along the Western Nepal fault system, a major fault zone that cuts obliquely across the high Himalaya in Nepal. Our study shows that all trenched faults ruptured during the Holocene, suggesting the potential for complex multifault ruptures and highlighting additional seismic hazards within the upper plate of the Himalayan megathrust, with possible linkages to megathrust earthquakes. Read the full article: #Paleoseismology #Earthquakes #Tectonics #Himalaya #SeismicHazards #ActiveFaults Photo by Gagan Raj Rai on Wikimedia Commons.