Greg Houseman - Academia.edu (original) (raw)
Papers by Greg Houseman
The spatial variation of strain rate in broad regions of continental collision, extension, or she... more The spatial variation of strain rate in broad regions of continental collision, extension, or shear can often be well represented by the deformation of a thin viscous shell representing the lithosphere. The simplest explanation of this observation is that the deformation of the lithosphere is to first order a ductile process, even though shallow focus earthquakes imply slip on faults and release of elastic strain. In the thin-viscous-shell concept the strain of the upper brittle layer is assumed to simply follow the ductile strain of the stronger layers beneath, at least in the inter-seismic period. If the faults extend only to depths of 10 or 20 km, the brittle upper layer is not sufficiently thick or strong to do otherwise, and the concept of the brittle upper layer controlled by the ductile substrate is consistent with ductile models of the displacement-rate field constrained by GNSS observations. However, some large-scale faults do not comply with this concept and, rather than f...
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Tellus A, 1977
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Determining the distribution of seismic hazard in the continents requires an understanding of how... more Determining the distribution of seismic hazard in the continents requires an understanding of how much deformation is accommodated by major faults. Quantifying the role of major faults in continental deformation has been hampered by a lack of high-resolution observations in the deforming interiors of continents. By combining surface movement data derived from 22,000 satellite radar images with data from sparse, ground-based GNSS stations we produce the first high-resolution present-day surface velocity field for the Tibetan Plateau and surrounding region, where the collision of rigid Indian lithosphere with Eurasia has created Earth’s largest and highest deforming region. We show that continental deformation is best characterized by a combination of continuous distributed deformation and focused strain on a few major fault systems.
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The dynamics of lithospheric deformation in the India-Eurasia collision zone has been debated ove... more The dynamics of lithospheric deformation in the India-Eurasia collision zone has been debated over many decades. Here we test a two-dimensional (2-D) Thin Viscous Shell (TVS) approach that has been adapted to explicitly account for displacement on major faults and investigate the impact of lateral variations in depth-averaged lithospheric strength. We present a suite of dynamic models to explain the key features from new high-resolution Sentinel-1 Interferometric Synthetic Aperture Radar (InSAR) as well as Global Navigation Satellite System (GNSS) velocities. Comparisons between calculated and geodetically observed velocity and strain rate fields indicate: (a) internal buoyancy forces from Gravitational Potential Energy (GPE) acting on a relatively weak region of highest topography (>2,000 m) contribute to dilatation of the high plateau and contraction on the margins; (b) a weak central Tibetan Plateau ~10^21 Pa s compared to far-field depth-averaged effective viscosity of 10^22 ...
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European Review, 2017
Istanbul and Bucharest are major European cities that face a continuing threat of large earthquak... more Istanbul and Bucharest are major European cities that face a continuing threat of large earthquakes. The geological contexts for these two case studies enable us to understand the nature of the threat and to predict more precisely the consequences of future earthquakes, although we remain unable to predict the time of those events with any precision better than multi-decadal. These two cities face contrasting threats: Istanbul is located on a major geological boundary, the North Anatolian Fault, which separates a westward moving Anatolia from the stable European landmass. Bucharest is located within the stable European continent, but large-scale mass movements in the upper mantle beneath the lithosphere cause relatively frequent large earthquakes that represent a serious threat to the city and surrounding regions.
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AGU Spring Meeting …, 2004
ABSTRACT
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Geophysical Research Letters, 2016
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The Carpathian Basins Project (CBP) aims to understand the origin of Miocene-age extensional basi... more The Carpathian Basins Project (CBP) aims to understand the origin of Miocene-age extensional basins, of which the Pannonian Basin is the largest, within the arc of the Alpine-Carpathian Mountain Ranges - a compressional structure. Analysis of the subsidence history of the Pannonian Basin shows that its mantle lithosphere has undergone a much greater degree of extension than the overlying crust.
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Geophysical Journal International, 1990
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ABSTRACT
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Journal of Geophysical Research, 2011
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Journal of Geophysical Research: Solid Earth, 2016
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Geophysical Journal International, 2001
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Geophysical Journal International, 1998
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Geophysical Journal International, 2013
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Solid Earth Discussions, 2018
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Geophysical Journal International, 2012
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Geophysical Journal International, 2020
SUMMARY Since the Mesozoic, central and eastern European tectonics have been dominated by the clo... more SUMMARY Since the Mesozoic, central and eastern European tectonics have been dominated by the closure of the Tethyan Ocean as the African and European plates collided. In the Miocene, the edge of the East European Craton and Moesian Platform were reworked in collision during the Carpathian orogeny and lithospheric extension formed the Pannonian Basin. To investigate the mantle deformation signatures associated with this complex collisional-extensional system, we carry out SKS splitting analysis at 123 broad-band seismic stations in the region. We compare our measurements with estimates of lithospheric thickness and recent seismic tomography models to test for correlation with mantle heterogeneities. Reviewing splitting delay times in light of xenolith measurements of anisotropy yields estimates of anisotropic layer thickness. Fast polarization directions are mostly NW–SE oriented across the seismically slow West Carpathians and Pannonian Basin and are independent of geological bound...
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Geophysical Research Letters, 2001
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Journal of Geophysical Research: Solid Earth, 2014
Bookmarks Related papers MentionsView impact
The spatial variation of strain rate in broad regions of continental collision, extension, or she... more The spatial variation of strain rate in broad regions of continental collision, extension, or shear can often be well represented by the deformation of a thin viscous shell representing the lithosphere. The simplest explanation of this observation is that the deformation of the lithosphere is to first order a ductile process, even though shallow focus earthquakes imply slip on faults and release of elastic strain. In the thin-viscous-shell concept the strain of the upper brittle layer is assumed to simply follow the ductile strain of the stronger layers beneath, at least in the inter-seismic period. If the faults extend only to depths of 10 or 20 km, the brittle upper layer is not sufficiently thick or strong to do otherwise, and the concept of the brittle upper layer controlled by the ductile substrate is consistent with ductile models of the displacement-rate field constrained by GNSS observations. However, some large-scale faults do not comply with this concept and, rather than f...
Bookmarks Related papers MentionsView impact
Tellus A, 1977
Bookmarks Related papers MentionsView impact
Determining the distribution of seismic hazard in the continents requires an understanding of how... more Determining the distribution of seismic hazard in the continents requires an understanding of how much deformation is accommodated by major faults. Quantifying the role of major faults in continental deformation has been hampered by a lack of high-resolution observations in the deforming interiors of continents. By combining surface movement data derived from 22,000 satellite radar images with data from sparse, ground-based GNSS stations we produce the first high-resolution present-day surface velocity field for the Tibetan Plateau and surrounding region, where the collision of rigid Indian lithosphere with Eurasia has created Earth’s largest and highest deforming region. We show that continental deformation is best characterized by a combination of continuous distributed deformation and focused strain on a few major fault systems.
Bookmarks Related papers MentionsView impact
The dynamics of lithospheric deformation in the India-Eurasia collision zone has been debated ove... more The dynamics of lithospheric deformation in the India-Eurasia collision zone has been debated over many decades. Here we test a two-dimensional (2-D) Thin Viscous Shell (TVS) approach that has been adapted to explicitly account for displacement on major faults and investigate the impact of lateral variations in depth-averaged lithospheric strength. We present a suite of dynamic models to explain the key features from new high-resolution Sentinel-1 Interferometric Synthetic Aperture Radar (InSAR) as well as Global Navigation Satellite System (GNSS) velocities. Comparisons between calculated and geodetically observed velocity and strain rate fields indicate: (a) internal buoyancy forces from Gravitational Potential Energy (GPE) acting on a relatively weak region of highest topography (>2,000 m) contribute to dilatation of the high plateau and contraction on the margins; (b) a weak central Tibetan Plateau ~10^21 Pa s compared to far-field depth-averaged effective viscosity of 10^22 ...
Bookmarks Related papers MentionsView impact
European Review, 2017
Istanbul and Bucharest are major European cities that face a continuing threat of large earthquak... more Istanbul and Bucharest are major European cities that face a continuing threat of large earthquakes. The geological contexts for these two case studies enable us to understand the nature of the threat and to predict more precisely the consequences of future earthquakes, although we remain unable to predict the time of those events with any precision better than multi-decadal. These two cities face contrasting threats: Istanbul is located on a major geological boundary, the North Anatolian Fault, which separates a westward moving Anatolia from the stable European landmass. Bucharest is located within the stable European continent, but large-scale mass movements in the upper mantle beneath the lithosphere cause relatively frequent large earthquakes that represent a serious threat to the city and surrounding regions.
Bookmarks Related papers MentionsView impact
AGU Spring Meeting …, 2004
ABSTRACT
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Geophysical Research Letters, 2016
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The Carpathian Basins Project (CBP) aims to understand the origin of Miocene-age extensional basi... more The Carpathian Basins Project (CBP) aims to understand the origin of Miocene-age extensional basins, of which the Pannonian Basin is the largest, within the arc of the Alpine-Carpathian Mountain Ranges - a compressional structure. Analysis of the subsidence history of the Pannonian Basin shows that its mantle lithosphere has undergone a much greater degree of extension than the overlying crust.
Bookmarks Related papers MentionsView impact
Geophysical Journal International, 1990
Bookmarks Related papers MentionsView impact
ABSTRACT
Bookmarks Related papers MentionsView impact
Journal of Geophysical Research, 2011
Bookmarks Related papers MentionsView impact
Journal of Geophysical Research: Solid Earth, 2016
Bookmarks Related papers MentionsView impact
Geophysical Journal International, 2001
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Geophysical Journal International, 1998
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Geophysical Journal International, 2013
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Solid Earth Discussions, 2018
Bookmarks Related papers MentionsView impact
Geophysical Journal International, 2012
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Geophysical Journal International, 2020
SUMMARY Since the Mesozoic, central and eastern European tectonics have been dominated by the clo... more SUMMARY Since the Mesozoic, central and eastern European tectonics have been dominated by the closure of the Tethyan Ocean as the African and European plates collided. In the Miocene, the edge of the East European Craton and Moesian Platform were reworked in collision during the Carpathian orogeny and lithospheric extension formed the Pannonian Basin. To investigate the mantle deformation signatures associated with this complex collisional-extensional system, we carry out SKS splitting analysis at 123 broad-band seismic stations in the region. We compare our measurements with estimates of lithospheric thickness and recent seismic tomography models to test for correlation with mantle heterogeneities. Reviewing splitting delay times in light of xenolith measurements of anisotropy yields estimates of anisotropic layer thickness. Fast polarization directions are mostly NW–SE oriented across the seismically slow West Carpathians and Pannonian Basin and are independent of geological bound...
Bookmarks Related papers MentionsView impact
Geophysical Research Letters, 2001
Bookmarks Related papers MentionsView impact
Journal of Geophysical Research: Solid Earth, 2014
Bookmarks Related papers MentionsView impact