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| Open AccessRiver thorium concentrations can record bedrock fracture processes including some triggered by distant seismic events
Daily measurements of the river concentration of the ultra-trace element thorium (Th) can provide a novel signature of bedrock fracture processes
- Benjamin Gilbert
- , Sergio Carrero
- & Kenneth H. Williams
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Article
| Open AccessVelocity-dependent heat transfer controls temperature in fracture networks
Heat transfer in a fracture network is heterogeneous as it depends pre-dominantly on flow velocity and fracture aperture. This finding has direct implications for the heat distribution and exploitation in geothermal and associated natural systems.
- Thomas Heinze
- & Nicola Pastore
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Article
| Open AccessGlobal thermal spring distribution and relationship to endogenous and exogenous factors
Data from 6000 geothermal areas worldwide are analyzed with a machine learning approach. The analysis suggests and confirms a dominant role of the terrestrial heat flow, topography, volcanism and extensional tectonics.
- G. Tamburello
- , G. Chiodini
- & C. Masciantonio
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| Open AccessShallow subsurface heat recycling is a sustainable global space heating alternative
Using shallow geothermal energy systems to recycle the heat accumulating in the subsurface due to climate change and urbanization is a feasible, sustainable, and opportunistic alternative to conventional space heating in the face of climate change
- Susanne A. Benz
- , Kathrin Menberg
- & Barret L. Kurylyk
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Matters Arising
| Open AccessMultiple induced seismicity mechanisms at Castor underground gas storage illustrate the need for thorough monitoring
- Víctor Vilarrasa
- , Silvia De Simone
- & Antonio Villaseñor
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Article
| Open AccessTransient evolution of permeability and friction in a slowly slipping fault activated by fluid pressurization
The mechanisms of permeability and friction evolution in a natural fault are investigated in situ. The authors conclude that the transient evolution of fault permeability and friction caused by a pressure perturbation exerts a potentially dominant control on fault stability during fluid flow
- Frédéric Cappa
- , Yves Guglielmi
- & Louis De Barros
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| Open AccessFluid-injection-induced earthquakes characterized by hybrid-frequency waveforms manifest the transition from aseismic to seismic slip
Yu et al. report a new type of induced earthquake signal characterized by hybrid-frequency waveforms (EHW). The low-frequency source features of the EHWs suggest they may represent slow ruptures transitioning from aseismic to seismic slip.
- Hongyu Yu
- , Rebecca M. Harrington
- & Bei Wang
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| Open AccessLithium systematics in global arc magmas and the importance of crustal thickening for lithium enrichment
The exact origin of lithium enrichment in arc magmatic systems is unclear. Here the authors conduct a global systematics of lithium, explaining why volcanic arcs built on thickened crust are most lithium-enriched, which sheds light on the future exploration of lithium resources.
- Chen Chen
- , Cin-Ty A. Lee
- & Weidong Sun
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| Open AccessHigh density oilfield wastewater disposal causes deeper, stronger, and more persistent earthquakes
Oilfield wastewater is commonly discarded by pumping it into deep geologic formations, but this process is now known to cause earthquakes. Here, he authors show that high-density oilfield wastewater may sink deeper in the Earth’s crust than previously considered possible, thus increasing fluid pressure and inducing earthquakes for years after injection rates decline.
- Ryan M. Pollyea
- , Martin C. Chapman
- & Hao Wu
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Article
| Open AccessGlobal patterns of nitrate storage in the vadose zone
Current global-scale nitrogen (N) budgets quantifying anthropogenic impacts on the N cycle do not explicitly consider nitrate storage in the vadose zone. Here, using estimates of depth to groundwater and nitrate leaching between 1900–2000, the authors show that the vadose zone is an important store of nitrate.
- M. J. Ascott
- , D. C. Gooddy
- & A. M. Binley
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Article
| Open AccessTremor activity inhibited by well-drained conditions above a megathrust
Low-frequency earthquakes (LFEs) in megathrusts are due to weak shear strength and high fluid pressure, but controls on LFE location remain unclear. Nakajima and Hasegawa show that LFE occurrence is limited to beneath unmetamorphosed undrained portions of the overlying plate.
- Junichi Nakajima
- & Akira Hasegawa
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Article
| Open AccessDiscovery of relict subglacial lakes and their geometry and mechanism of drainage
Our understanding of subglacial lake drainage events is limited by a lack of direct observations. Here, the authors use ground penetrating radar to identify a relict subglacial lake and infer drainage mechanisms based on geomorphological features.
- Stephen J. Livingstone
- , Daniel J. Utting
- & Andrew C. Fowler
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Article
| Open AccessTimescales of methane seepage on the Norwegian margin following collapse of the Scandinavian Ice Sheet
Understanding the timescales of gas hydrate dissociation and methane release are critical to gauge the potential climate impact. Here, the authors report a methane efflux chronology from five sites in Barents and Norwegian seas and show methane release coincident with the release of ice sheet-induced pressure.
- Antoine Crémière
- , Aivo Lepland
- & Harald Brunstad
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Article
| Open AccessGroundwater–surface water mixing shifts ecological assembly processes and stimulates organic carbon turnover
Groundwater-surface water mixing zones link critical ecosystem domains, but attendant microbe-biogeochemistry-hydrology interactions are poorly known. Here, the authors show that groundwater-surface water mixing stimulates respiration, alters carbon composition, and shifts the ecology from stochastic to deterministic.
- James C. Stegen
- , James K. Fredrickson
- & Malak Tfaily
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Article
| Open AccessApproaching a universal scaling relationship between fracture stiffness and fluid flow
Fractures in rock can be altered geochemically and deformed under stress, affecting fluid flow rates across many orders of magnitude. Here, the authors present a universal scaling relationship between fluid flow and fracture specific stiffness, which will aid the interpretation of subsurface sites.
- Laura J. Pyrak-Nolte
- & David D. Nolte
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Article |
Lost cold Antarctic deserts inferred from unusual sulfate formation and isotope signatures
Due to a paucity of terrestrial data, knowledge of the size of the East Antarctic ice sheet in the past is limited. Here, the authors present isotope data of sulfates from the Lewis Cliff Ice Tongue moraine, which suggest temporary existence of ice-free conditions in central Antarctica since the Miocene.
- Tao Sun
- , Richard A. Socki
- & Eric Tonui
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| Open AccessSustainability and dynamics of outcrop-to-outcrop hydrothermal circulation
Much hydrothermal circulation occurs away from the mid-ocean ridges and out on ridge flanks, affecting lithospheric heat deficit, solute fluxes, and influencing the biosphere. Here, the authors use 3D simulations to look at what controls the circulation and flow rate between and through seamounts.
- Dustin M. Winslow
- & Andrew T. Fisher
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| Open AccessAmbient seafloor noise excited by earthquakes in the Nankai subduction zone
Excitations of seismic background noise are mostly related to fluid disturbances, and earthquakes have not been considered as a source due to their intermittent nature. Here, the authors use a seabed hydrophone array and show that background noise offshore Japan is mainly due to small earthquakes.
- Takashi Tonegawa
- , Yoshio Fukao
- & Yoshiyuki Kaneda