Article
Geochemistry & Geophysics
Alican Aktag, Kaan Sayit, Bradley J. Peters, Tanya Furman, Jorg Rickli
Summary: Quaternary Elazig mafic alkaline volcanism provides crucial insights into the chemical nature of the mantle source domains beneath eastern Turkey, revealing compositional similarities to global OIBs and MORBs.
Article
Geology
Luan C. Nguyen, Alan Leyander, Fenglin Niu, Julia Morgan, Guoliang Li
Summary: The continental rifting that precedes the formation of a new ocean basin exhibits significant variations along strike. By studying the continental rifting process that formed the margins of the Gulf of Mexico, researchers have discovered variations in seismic velocity in the mantle lithosphere. They found that mantle refertilization and lithosphere thickness control deformation style and along-strike variations in continental rifting.
Article
Geosciences, Multidisciplinary
Yingkai Wu, Xuewei Bao, Bingfeng Zhang, Yixian Xu, Wencai Yang
Summary: By stacking receiver functions, the structure of the mantle transition zone beneath western Tibet and Himalaya has been imaged, revealing evidence of the detached Lhasa lithospheric mantle and recently delaminated Qiangtang lithosphere in the study area. The small dependence of d410 amplitude on frequency indicates the anhydrous nature of the MTZ.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geochemistry & Geophysics
Tao Xu, Yinshuang Ai, Chenglong Wu, Ling Chen, Enbo Fan, Long Li, Weiyu Dong
Summary: By quantifying the shear wave splitting parameters captured by three seismic arrays in Northeast China, we studied the origin of intraplate volcanism and found a toroidal pattern of anisotropy beneath the Songliao Basin. The high-density seismic array revealed that the Pacific subduction and lithospheric foundering processes controlled the genesis of late Cenozoic volcanism in Northeast China.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geosciences, Multidisciplinary
Junlin Hua, Karen M. Fischer, Thorsten W. Becker, Esteban Gazel, Greg Hirth
Summary: The asthenosphere is crucial for plate tectonics, as its low viscosity controls mantle convection that affects the Earth's surface. The origin and impact of partial melting in the asthenosphere remain unclear. Through analysis of seismic data, we found globally widespread evidence for a low-velocity zone at the base of the asthenosphere. This zone is most commonly detected in regions with higher upper-mantle temperatures and is likely a partially molten layer.
Article
Geosciences, Multidisciplinary
Jianhua Li, Shuwen Dong, Peter A. Cawood, Hans Thybo, Peter D. Clift, Stephen T. Johnston, Guochun Zhao, Yueqiao Zhang
Summary: The wide-mode lithospheric extension in South China is characterized by a transition from a magma-poor to a magma-rich domain, resulting in crustal melting, crust-mantle decoupling, and the formation of Moho uplift associated with mantle shear zones. The strain fields in the South China lithosphere are uniformly oriented in the NW-SE direction, indicating vertically coherent deformation. Slab rollback and mantle flow likely drove the lithospheric extension in South China.
EARTH-SCIENCE REVIEWS
(2023)
Article
Geochemistry & Geophysics
Florence D. C. Ramirez, Clinton P. Conrad, Kate Selway
Summary: This study investigates the relationship between the prominent seismic low-velocity zone (LVZ) and the low seismic Q zone (LQZ) in the oceanic low-viscosity asthenosphere, and suggests that small olivine grain sizes may be the cause of these seismic and rheological properties. A self-consistent analytical 1-D channel flow model is developed to determine the dominant flow patterns in the upper mantle, taking into account its rheology and its dependence on flow-modified grain-sizes, water content, and melt fraction. The study finds that a plug flow configuration best explains the LQZ in the asthenosphere, and this can be attributed to significant grain-size reduction due to extensive shearing across the asthenosphere.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Geochemistry & Geophysics
Jing Liu, Jianping Wu, Weilai Wang, Yan Cai, Lihua Fang
Summary: The study focused on seismic anisotropy around the Ordos Block, finding that the central and eastern regions have a relatively thick and rigid lithosphere, while the western lithosphere may have undergone significant deformation due to expansion and compression of the Tibetan Plateau. Anisotropy near the Datong Basin is related to the compression direction of the Tibetan Plateau, while the central part of the Shanxi Rift shows weaker anisotropy.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Ruo Jia, Dapeng Zhao, Jianping Wu
Summary: A robust 3-D imaging of the crust and upper mantle beneath NE China was achieved using seismic data. Various seismic anisotropy characteristics were observed at different depths and regions, reflecting the influence of geological structures and plate movements. Additionally, unique geological structures associated with volcanic activities were identified.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Zheng Tang, Jordi Julia, Walter D. Mooney, Paul Martin Mai, Huazhi Yu, Yanqiang Wu
Summary: We provide a comprehensive image of the mantle transition zone beneath northeastern China, revealing fine-scale topography and lateral variations in thickness and slab interfaces within the zone. The images provide direct evidence for the presence of the stagnant Pacific subducting slab and support previous hypotheses of mantle upwelling triggered by the sinking of the stagnant slab.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geosciences, Multidisciplinary
Chen Zhang, Zhen Guo, Yong Yu, Ting Yang, Yongshun John Chen
Summary: In this study, we used P and S receiver functions to obtain the crustal and lithospheric structures of the Ordos block in the western North China Craton. The results show that the Ordos block has a thick lithosphere, while the lithosphere is significantly thinner in its surrounding rift systems. Furthermore, the northern margin of the Ordos block is heavily modified by mantle upwelling, whereas the southern margin has little modification from eastward lateral asthenospheric flow.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geochemistry & Geophysics
Yu Wei, Shuangxi Zhang, Mengkui Li, Tengfei Wu, Yujin Hua, Yu Zhang, Jianfeng Cai
Summary: In this study, a 3-D S-wave velocity model was constructed to reveal the characteristics of the Qinling-Dabie orogenic belt and its collision processes and tectonic evolution with the North China Block and Yangtze Block. The results support a two-stage exhumation model for the high-pressure/ultra-high-pressure rocks and provide evidence for the delamination of the lower crust in the orogenic belt.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Cunrui Han, Zhouchuan Huang, Shijie Hao, Liangshu Wang, Mingjie Xu, James O. S. Hammond
Summary: Constraining variations of lithospheric structure and deformation in southeastern Tibet and the surrounding region is crucial for understanding the lateral growth of the plateau. Researchers used seismic data and tomography techniques to obtain high-resolution velocity and anisotropy distributions of the crust and upper mantle. They found that the Dianzhong Block plays a significant role in the evolution of the plateau, hindering the migration of plateau material and causing localized deformation in the surrounding areas.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geosciences, Multidisciplinary
Shivam Chandra, Kajaljyoti Borah, Avilash Barua, Pousali Mukherjee
Summary: Anisotropy in the upper mantle of Sri Lanka region was investigated using seismic wave velocity variation in different directions. The results revealed the presence of two anisotropic layers, with NW-SE and NE-SW polarization directions in the upper layer, and NNE-SSW and NW-SE polarization directions in the lower layer. The overall fast polarization direction for Sri Lanka was found to be NE-SW. The observed delay time in the lower layer described a 134 km thick anisotropic layer with 4% anisotropy. The anisotropy in Sri Lanka is mainly controlled by asthenospheric flow and partially influenced by lithospheric mantle.
JOURNAL OF EARTH SYSTEM SCIENCE
(2023)
Article
Geochemistry & Geophysics
F. Salajegheh, J. C. Afonso
Summary: Geoid anomalies provide crucial information about the Earth's internal density structure. Researchers have developed a representative upper mantle geoid model using spherical harmonic analysis, showing significant contributions from degrees 5 and 6.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geochemistry & Geophysics
Thomas S. Hudson, J-Michael Kendall, Matthew E. Pritchard, Jonathan D. Blundy, Joachim H. Gottsmann
Summary: Uturuncu volcano in the Bolivian Andes is seismically active and lies above the world's largest silicic partial melt. Analysis of seismic activity reveals fault orientations and potential fluid migration mechanisms. The study suggests using moment magnitudes for accurate b-value analysis and interprets b-values > 1 in terms of fluid-enhanced seismicity.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Environmental Sciences
Sam Fankhauser, Stephen M. Smith, Myles Allen, Kaya Axelsson, Thomas Hale, Cameron Hepburn, J. Michael Kendall, Radhika Khosla, Javier Lezaun, Eli Mitchell-Larson, Michael Obersteiner, Lavanya Rajamani, Rosalind Rickaby, Nathalie Seddon, Thom Wetzer
Summary: The concept of net-zero carbon emissions is rooted in physical climate science but is operationalized through social, political, and economic systems. Seven critical attributes have been identified for the successful implementation of net zero, emphasizing the urgency of emission reductions, coverage of all emission sources, cautious use of carbon dioxide removals, and alignment with broader sustainable development objectives.
NATURE CLIMATE CHANGE
(2022)
Article
Geochemistry & Geophysics
Shoh Tagawa, George Helffrich, Kei Hirose, Yasuo Ohishi
Summary: The study investigates the melting curve of non-magnetic FeH at high pressures, revealing it forms a eutectic system with Fe and melts at temperatures higher than previously known. The slope of the FeH melting curve is comparable to that of Fe, indicating little change in eutectic liquid composition with increasing pressure.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Geosciences, Multidisciplinary
Tom Kettlety, J. Michael Kendall, Diana C. Roman
Summary: Estimating the volume of intruded magma is crucial for predicting volcanic activity. Geodetic modeling is a useful tool for providing these estimates, but it has limitations in submarine and highly vegetated areas. This study explores the use of seismic moment release estimates as a complementary approach. By comparing the moment-volume scaling of several volcanic earthquake sequences and injection-induced seismicity, the researchers find a notable similarity in scaling within the volcanic sequences. This suggests a distinctive geological condition for volcanoes compared to induced seismicity settings, and the possibility of estimating intruded volume without geodetic information.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
Wen Zhou, Antony Butcher, Alex M. Brisbourne, Sofia-Katerina Kufner, J-Michael Kendall, Anna L. Stork
Summary: Distributed Acoustic Sensing (DAS) and seismic noise interferometry (SI) can be used for glacier measurements and near-surface studies. We propose two approaches to improve DAS and seismic noise cross-correlation results.
JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE
(2022)
Article
Multidisciplinary Sciences
Stephen P. Hicks, Lidong Bie, Catherine A. Rychert, Nicholas Harmon, Saskia Goes, Andreas Rietbrock, Songqiao Shawn Wei, Jenny S. Collier, Timothy J. Henstock, Lloyd Lynch, Julie Prytulak, Colin G. Macpherson, David Schlaphorst, Jamie J. Wilkinson, Jonathan D. Blundy, George F. Cooper, Richard G. Davy, John -Michael Kendall
Summary: Volatiles expelled from subducted plates affect the melting of the overlying mantle, which is important for arc volcanism. This study examines seismic attenuation beneath the Lesser Antilles arc and reveals the role of expelled fluids and melt in controlling volcanism. The results show that cold boundary layers transport fluids towards the back-arc, while warm mantle beneath the back-arc feeds arc volcanoes.
Article
Geochemistry & Geophysics
David Schlaphorst, Catherine A. Rychert, Nicholas Harmon, Stephen P. Hicks, Petros Bogiatzis, J-Michael Kendall, Rachel E. Abercrombie
Summary: Seismicity along transform faults provides important constraints for understanding earthquake ruptures. This study presents the first local seismicity catalog of slow spreading ridges based on data recorded by a temporary broad-band network. Most of the earthquakes are located along the Chain Transform Fault, Romanche transform fault, and the Mid-Atlantic Ridge. The seismic events are characterized by normal faulting along the ridge and strike-slip faulting along the transforms, with some reverse mechanisms.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geosciences, Multidisciplinary
T. S. Hudson, J. M. Kendall, J. D. Blundy, M. E. Pritchard, P. MacQueen, S. S. Wei, J. H. Gottsmann, S. Lapins
Summary: Mapping fluid distribution in the crust below Uturuncu volcano using seismic attenuation tomography reveals partially and fully fluid-saturated areas along aligned faults and fractures. Pressure-temperature profiles and conductivity data help identify the likely fluid composition, with shallow regions of dry and H2O/brine-saturated crust, and a deeper supercritical H2O/brine column. These observations provide insights into Uturuncu's transcrustal hydrothermal system and demonstrate the potential application of such methods for mapping crustal fluid pathways and hydrothermal/geothermal systems.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geosciences, Multidisciplinary
T. S. Hudson, S. K. Kufner, A. M. Brisbourne, J. M. Kendall, A. M. Smith, R. B. Alley, R. J. Arthern, T. Murray
Summary: This study investigates the slip of glaciers over the underlying bed, which is the dominant mechanism governing the migration of ice into the oceans and contributes to sea-level rise. The researchers use passive seismic observations to measure frictional shear stress and slip at the bed of the Rutford Ice Stream in Antarctica. They find that basal shear stresses and slip rates vary significantly in both space and time, indicating that the bed is more complex than previously assumed in ice stream models. This research provides important constraints for ice-dynamics models and is critical for understanding the contribution of ice mass loss to sea-level rise.
Article
Geosciences, Multidisciplinary
S. -K. Kufner, J. Wookey, A. M. Brisbourne, C. Martin, T. S. Hudson, J. M. Kendall, A. M. Smith
Summary: The crystal orientation fabric of glacier ice is crucial in determining its strength and flow behavior, making it an important factor in ice flow modeling. In this study, the authors demonstrate that shear-wave splitting (SWS) measured through glacial microseismicity can be used to infer seismic anisotropy and ice fabric in a statistical sense. By analyzing over 200,000 SWS measurements from a seismic network near Rutford Ice Stream in Antarctica, the researchers were able to identify a three-layer ice fabric structure with varying strengths and deformability along the flow direction. Their findings suggest that fast-flowing ice streams may require a more complex integration of viscosity in ice sheet models.
JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE
(2023)
Article
Geochemistry & Geophysics
M. Gauntlett, T. Hudson, J. -M. Kendall, N. Rawlinson, J. Blundy, S. Lapins, B. Goitom, J. Hammond, C. Oppenheimer, G. Ogubazghi
Summary: Understanding the crustal structure and the movement of fluids beneath a volcano is crucial for assessing volcanic hazard and exploring geothermal potential. This study uses earthquake tomography to image the seismic velocity structure beneath Nabro volcano in Ethiopia. The findings suggest the presence of solidified rocks and a primary melt storage region that fed the 2011 eruption. The observations also indicate the persistence of magma and the potential for geothermal exploration.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geochemistry & Geophysics
K. Leptokaropoulos, C. A. Rychert, N. Harmon, J. M. Kendall
Summary: Based on the study of the Chain transform in the equatorial Mid-Atlantic, it is found that the seismic activity is highest in the eastern area, while the western and central areas have lower seismic rates but release the majority of seismic moment. This segmentation is possibly due to variable fluid circulation and alteration.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geology
J. M. Kendall, D. Schlaphorst, C. A. Rychert, N. Harmon, M. Agius, S. Tharimena
Summary: Parallel melt accumulation along the Mid-Atlantic Ridge was found, and this may enhance the driving forces of the plates.
Article
Geochemistry & Geophysics
J. Kemper, A. Khan, G. Helffrich, M. van Driel, D. Giardini
Summary: In this study, we used self-consistently built models of the seismic structure of the Earth to invert a large set of normal-mode centre-frequencies and quality factors. Our findings show that the mantle P- and S-wave velocities need to be slightly adjusted to fit the observations, while the outer-core P-wave velocity is slower due to a different velocity gradient. In terms of density, the lower mantle is less dense and the outer core is more dense than previously thought.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)