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)
Letter
Geosciences, Multidisciplinary
Ryan Porter, Mary Reid
Summary: The thermal regime of the continental lithosphere in North America was evaluated using seismic observations and lab results to estimate temperatures and lithospheric thickness, as well as predict melt distribution in the upper mantle. Results indicate thinner lithosphere and presence of melt in the western US, while thicker lithosphere with absence of melt is observed in the central and eastern US.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geochemistry & Geophysics
Sungho Lee, Arushi Saxena, Jung-Hun Song, Junkee Rhie, Eunseo Choi
Summary: This study aims to understand the stress field of the Korean Peninsula using numerical simulations and seismic tomography. The results suggest that crustal and upper-mantle heterogeneities are responsible for the seismic activity in the region. Compressional stress and mantle heterogeneities control the seismicity in the western area, while a correlation is found between relatively thin lithosphere and strong upper-mantle upwelling with the seismic activity in the eastern area.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Qingyun Deng, Zhen Zhong, Mao Ye, Wensong Zhang, Denggao Qiu, Chong Zheng, Jianguo Yan, Fei Li, Jean-Pierre Barriot
Summary: By modeling mass-related loads and lithospheric deflection and analyzing gravity and topography data, the elastic thickness of the lithosphere is determined. In regions with mantle plugs, accurate models are difficult to develop without considering mantle uplift. A lithospheric loading model for large impact basins was developed in this study, which does not assume compensation and utilizes high-resolution crustal thickness data. The elastic thickness obtained through fitting the observed data reflects the lithospheric temperature at the end of the super-isostatic process. Sensitivity analysis suggests the importance of modeling impact-induced loads for understanding mascon formation.
JOURNAL OF GEOPHYSICAL RESEARCH-PLANETS
(2023)
Review
Astronomy & Astrophysics
Jessica M. Warren, Lars N. Hansen
Summary: The strength of lithospheric plates, which is governed by brittle and ductile processes, is a key factor in plate tectonics. Experimental studies on olivine, the main mineral in the lithosphere, reveal that it deforms through various mechanisms including low-temperature plasticity, dislocation creep, and grain-boundary sliding. While deformation in most of the lithosphere is dominated by grain-boundary sliding, shear zones exhibit diffusion creep and the brittle-ductile transition may involve low-temperature plasticity. There is a discrepancy between observations from naturally deformed rocks and geophysical predictions, possibly due to uncertainties in the brittle-ductile transition where the lithosphere is strongest.
ANNUAL REVIEW OF EARTH AND PLANETARY SCIENCES
(2023)
Article
Geochemistry & Geophysics
Suzanne Atkins, Nicolas Coltice
Summary: High lateral viscosity variations are required to produce Earth-like values of lithospheric net rotation (LNR). Other factors such as the presence of continents and a viscosity gradient at the transition zone also play important roles in determining the magnitude of net rotation. Additionally, the evolution of LNR is too complicated to predict in models, but the range of LNR within simulations follows a Gaussian distribution with a correlation time of 5 Myr.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geochemistry & Geophysics
C. Weidle, L. Wiesenberg, A. Scharf, P. Agard, A. El-Sharkawy, F. Krueger, T. Meier
Summary: The geodynamic evolution of Eastern Arabia consists of three main events: Pan-African plate assembly, Infracambrian and Ordovician extension, and Permian Pangean breakup and rifting. The obduction of the Semail Ophiolite during the Late Cretaceous and the subsequent relaxation of the lithosphere are also significant. Seismological observations reveal the lithospheric thickness and crustal heterogeneity of Eastern Arabia, indicating the segmentation of the crust and the impact of various tectonic events. The configuration of the lithosphere in northeastern Arabia preserves imprints from multiple geological periods.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Geochemistry & Geophysics
N. Bulut, H. Thybo, V Maupin
Summary: This study presents a P-wave velocity model of the upper mantle in Fennoscandia obtained from finite-frequency body-wave tomography. The model reveals a strong negative velocity anomaly in Norway, which may provide isostatic support to the high topography of the Scandinavian mountain range. Additionally, strong positive velocity anomalies are observed around the southern Bothnian Bay and the Baltic Sea.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
Omid Bagherpur Mojaver, Fiona Darbyshire, Riddhi Dave
Summary: The study reveals significant variations in seismic velocities across different tectonic zones, with no simple relation found between lithospheric thicknesses and ages. The lithosphere-asthenosphere boundary in the study area is located at depths of 70-120 km, with the thickest and fastest lithosphere beneath New Brunswick.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geochemistry & Geophysics
Valerie Maupin, Alexandra Mauerberger, Frederik Tilmann
Summary: The study analyzes the radial anisotropy in the upper mantle of the Fennoscandian Shield using joint inversion of Love and Rayleigh wave phase velocities. Similar radial anisotropy is found in subregions down to at least 200 km depth, with SH waves faster than SV by 2%-3%. Different types of olivine crystallographic preferred orientations (CPOs) are discussed in relation to seismic observations.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Geochemistry & Geophysics
Mengfan Jiang, Weijia Sun, Jiamin Hu, Qingya Tang
Summary: The uppermost mantle is a crucial region linking the lower crust and lithospheric mantle and carries important dynamic and structural information. By analyzing the Sn wave propagation efficiency, researchers have provided strong constraints on the lateral and depth variations in the inefficient Sn wave zone beneath the Tibetan Plateau. The results show the widespread distribution of the seismic attenuation structure or partial melt in the uppermost mantle, and suggest that asthenospheric materials might upwell and flow laterally beneath the Tibetan Plateau, providing a thermal driving force for the uplift of the plateau and the deformation of the crust-mantle structure.
Article
Geosciences, Multidisciplinary
Zachary C. Eilon, Lun Zhang, James B. Gaherty, Donald W. Forsyth, Joshua B. Russell
Summary: This study provides observational support for small-scale convective rolls beneath the oceanic plates. The study found alternating upper mantle velocity anomalies aligned with gravity lineations beneath the seafloor. These anomalies, likely caused by temperature variations and possible partial melting, are strongest in deeper regions, indicating rapid vertical motions through a low-viscosity asthenospheric channel.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geochemistry & Geophysics
Hannah E. Krueger, Isabella Gama, Karen M. Fischer
Summary: This study aims to constrain the origins of layering in the seismic velocity structure within the cratonic mantle lithosphere. Negative Mid-Lithospheric Discontinuities (MLDs) were found to be common but intermittent, with shear velocity drops of 1%-4%. These negative MLDs are more strongly correlated with tectonic and metasomatic activity long after craton formation, rather than age-related variations in mantle composition.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2021)
Article
Geosciences, Multidisciplinary
Yixian Xu, Yi Zhang, Bo Yang, Xuewei Bao
Summary: This study presents a method to reconstruct the Paleozoic-lithospheric structures of the North China Craton (NCC) and reveals that there was massive thinning in the eastern East Block (EB) after the Paleozoic, while thickening occurred in the northern Ordos Basin and the region from the Weibei uplift to the South Taihang Mountains uplift. The calculated self-sustaining oscillation periods are in good agreement with the periodicity observed in the sedimentation rate of the Ordos Basin and basaltic underplating events in the Trans-North China Orogen. The results suggest that, apart from the EB, the Phanerozoic lithospheric modification of the NCC is mainly controlled by heat conduction and dissipation through the cratonic lithosphere.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geochemistry & Geophysics
Eric L. Brown, Tyrone O. Rooney, Robert Moucha, Seth Stein, Carol A. Stein
Summary: The study investigates the magma generation factors of the Midcontinent Rift in North America by combining mantle potential temperature and lithospheric thickness constraints. It reveals that the early stage of continental flood basalt magmatism was controlled by deep melting and high mantle potential temperatures, followed by a gradual decrease in temperature. Constraints on mantle potential temperature and lithospheric thickness suggest thinning lithosphere and decreasing mantle potential temperatures during the formation of the continental flood basalts.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geochemistry & Geophysics
Arben Pitarka, Robert J. Mellors, William R. Walter, Souheil Ezzedine, Oleg Vorobiev, Tarabay Antoun, Jeffery L. Wagoner, Eric M. Matzel, Sean R. Ford, Arthur J. Rodgers, Lewis Glenn, Mike Pasyanos
BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA
(2015)
Article
Engineering, Civil
Michael Pasyanos
EARTHQUAKE SPECTRA
(2015)
Article
Geochemistry & Geophysics
Michael E. Pasyanos, Rengin Gok, William R. Walter
BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA
(2016)
Article
Geochemistry & Geophysics
Rengin Gok, Ayoub Kaviani, Eric M. Matzel, Michael E. Pasyanos, Kevin Mayeda, Gurban Yetirmishli, Issa El-Hussain, Abdullah Al-Amri, Farah Al-Jeri, Tea Godoladze, Dogan Kalafat, Eric A. Sandvol, William R. Walter
BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA
(2016)
Article
Geochemistry & Geophysics
Mark D. Fisk, Michael E. Pasyanos
BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA
(2016)
Article
Geosciences, Multidisciplinary
G. A. Ichinose, S. C. Myers, S. R. Ford, M. E. Pasyanos, W. R. Walter
GEOPHYSICAL RESEARCH LETTERS
(2017)
Article
Geochemistry & Geophysics
Michael E. Pasyanos, Stephen C. Myers
SEISMOLOGICAL RESEARCH LETTERS
(2018)
Article
Geochemistry & Geophysics
William R. Walter, Douglas A. Dodge, Gene Ichinose, Stephen C. Myers, Michael E. Pasyanos, Sean R. Ford
SEISMOLOGICAL RESEARCH LETTERS
(2018)
Article
Geochemistry & Geophysics
Michael E. Pasyanos, Keehoon Kim
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2019)
Article
Geochemistry & Geophysics
Michael E. Pasyanos, Andrea Chiang
Summary: Moment tensor solutions are calculated for U.S. underground nuclear tests and forms an extensive database for evaluating monitoring tasks and testing explosion monitoring methodologies.
BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA
(2022)
Article
Geochemistry & Geophysics
Michael E. Pasyanos
Summary: Seismic moment, a measurable quantity of seismic sources, is used to estimate the yield of explosions. This study introduces a new method that utilizes a full moment tensor solution and an explosion source model to estimate the moment-to-yield ratio. The results obtained from applying this method to North Korean nuclear explosions align with other yield estimates.
SEISMOLOGICAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
Keehoon Kim, Michael E. E. Pasyanos
Summary: This study accurately estimates the size of the 2020 Beirut explosion using the inversion technique of infrasound, and provides a range of results through 3D numerical simulations and stochastic weather forecast models to comprehensively analyze the uncertainty of numerical modeling and estimated results. Additionally, the study demonstrates the significant advantage of the joint approach in seismoacoustic analysis.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geochemistry & Geophysics
Keehoon Kim, Michael E. Pasyanos
Summary: The Large Surface Explosion Coupling Experiment (LSECE) conducted in Yucca Flat at the Nevada National Security Site in 2020 aimed to provide ground-truth data for seismoacoustic wave excitation by large chemical explosions near the ground surface. The joint seismoacoustic analysis demonstrated the capability to improve accuracy of explosion yield and depth estimation.
BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA
(2023)
Article
Geochemistry & Geophysics
Sean R. Ford, Michael E. Pasyanos, Andrea Chiang
Summary: This study uses the Pasyanos and Chiang (2022) dataset to calculate the seismic moment of explosions and validate the relationship between explosive yield and seismic moment. By correcting the seismic moment and testing multiple explanatory variables, a simple model for predicting explosive yield is obtained.
BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA
(2023)
Article
Geochemistry & Geophysics
Moira L. Pyle, William R. Walter, Michael E. Pasyanos
BULLETIN OF THE SEISMOLOGICAL SOCIETY OF AMERICA
(2017)