Section 12.1
... 12.1 What causes earthquakes? • The seismic waves from an earthquake are usually strongest at the epicenter, the point on the surface right above the focus. ...
... 12.1 What causes earthquakes? • The seismic waves from an earthquake are usually strongest at the epicenter, the point on the surface right above the focus. ...
World of quakes - Science Learning Hub
... Give the seismologists Part 1 – seismologist instructions and World map for seismologists. Give the vulcanologists Part 1 – vulcanologist instructions and World map for vulcanologists. The maps do not have country or region names on them, so you might like to have a general world map somewhere i ...
... Give the seismologists Part 1 – seismologist instructions and World map for seismologists. Give the vulcanologists Part 1 – vulcanologist instructions and World map for vulcanologists. The maps do not have country or region names on them, so you might like to have a general world map somewhere i ...
Faulting and hydration of the Juan de Fuca plate system
... accumulated during the time-stratigraphic period A have an average thickness of some 30 m while the estimated cumulative fault throw during this period is 1.17 ± 0.18 m, less than the resolution threshold for our images. This suggests that plate-deforming processes have remained active during most r ...
... accumulated during the time-stratigraphic period A have an average thickness of some 30 m while the estimated cumulative fault throw during this period is 1.17 ± 0.18 m, less than the resolution threshold for our images. This suggests that plate-deforming processes have remained active during most r ...
Plate tectonic controls on atmospheric CO2 levels since the Triassic
... subduction rates as we see no geodynamic cause why the process of subduction and the mechanical interaction between slab and mantle should have significantly changed over the past few hundred million years. This may be further illustrated by the observation that the global average of slab-sinking ra ...
... subduction rates as we see no geodynamic cause why the process of subduction and the mechanical interaction between slab and mantle should have significantly changed over the past few hundred million years. This may be further illustrated by the observation that the global average of slab-sinking ra ...
Subduction Zones of the World: Comparison to the Cascadia
... transformational faulting related to phase transitions in the deep part of the upper mantle. In Kamchatka, resumption of seismic activity starts at 400–500 km. ...
... transformational faulting related to phase transitions in the deep part of the upper mantle. In Kamchatka, resumption of seismic activity starts at 400–500 km. ...
Eclogite formation and the rheology, buoyancy, seismicity, and H2O
... aphyric pillows and rare brecciatedflows and massive flows [Ernewein et al., 1988]. ...
... aphyric pillows and rare brecciatedflows and massive flows [Ernewein et al., 1988]. ...
1 Accretion of terranes and growth of continental crust along the
... continental rifting to be latest Precambrian (543 Ma) (summary in Thomas, 1991). Repeated episodes of Appalachian orogenesis have obliterated any possible off-shelf continental slope-and-rise deposits; however, a robust Cambrian-Ordovician passivemargin carbonate-shelf facies documents the early pos ...
... continental rifting to be latest Precambrian (543 Ma) (summary in Thomas, 1991). Repeated episodes of Appalachian orogenesis have obliterated any possible off-shelf continental slope-and-rise deposits; however, a robust Cambrian-Ordovician passivemargin carbonate-shelf facies documents the early pos ...
Lecture W6-L15-17
... Exploiting shear zones is an alternate way to bring the magmas to the surface. It’s basically quite similar to dykes, except that tectonic deformation in the shear zone will help to build the pressure and move the magmas upwards. At high structural levels, the shear zones will turn into faults, that ...
... Exploiting shear zones is an alternate way to bring the magmas to the surface. It’s basically quite similar to dykes, except that tectonic deformation in the shear zone will help to build the pressure and move the magmas upwards. At high structural levels, the shear zones will turn into faults, that ...
The Bent Hawaiian-Emperor Hotspot Track
... show that a number of ridges have crossed the Pacific since 140 Ma at velocities of several centimeters per year (29). Thus, this ridge migration could have captured mantle plumes through flow directed at the ridge. If the ridge moves beyond that distance, a captured plume would presumably return to ...
... show that a number of ridges have crossed the Pacific since 140 Ma at velocities of several centimeters per year (29). Thus, this ridge migration could have captured mantle plumes through flow directed at the ridge. If the ridge moves beyond that distance, a captured plume would presumably return to ...
Shervais, J.W., Significance of Subduction
... The implication of this thermal convection model is that even though mafic crust resembling modern oceanic crust, or oceanic plateaux, may have formed, there is no assurance that this crust was destroyed along Phanerozoic-style, asymmetrical subduction zones. Sinking of mafic and ultramafic crust al ...
... The implication of this thermal convection model is that even though mafic crust resembling modern oceanic crust, or oceanic plateaux, may have formed, there is no assurance that this crust was destroyed along Phanerozoic-style, asymmetrical subduction zones. Sinking of mafic and ultramafic crust al ...
Updated Plate Tectonics
... Possible Causes of Tectonic Plate Motion • Movement of the Asthenosphere: The solid rock of the asthenosphere flows very slowly. This movement occurs because of changes in density within the asthenosphere. These density changes are caused by the outward flow of thermal energy from deep within the Ea ...
... Possible Causes of Tectonic Plate Motion • Movement of the Asthenosphere: The solid rock of the asthenosphere flows very slowly. This movement occurs because of changes in density within the asthenosphere. These density changes are caused by the outward flow of thermal energy from deep within the Ea ...
Plate tectonics and petroleum basins
... superimposed upon a late Paleozoic-early Mesozoic continental rifting during which the lower crust rifted continental-margin). was tectonically thinned and invaded by dense Numerous basin classification and basin mantle material, both processes effecting regional formation schemes have been offered ...
... superimposed upon a late Paleozoic-early Mesozoic continental rifting during which the lower crust rifted continental-margin). was tectonically thinned and invaded by dense Numerous basin classification and basin mantle material, both processes effecting regional formation schemes have been offered ...
Buildup of a dynamically supported orogenic plateau: Numerical
... and Diament, 1995, Appendix A] with a thermotectonic age of 65 Ma. The corresponding thermal boundary conditions include zero out-flux at lateral boundaries, fixed temperatures at the upper surface and the bottom of the model (T 5 0 C at the surface and T 5 1330 C at the bottom of the lithosphere). ...
... and Diament, 1995, Appendix A] with a thermotectonic age of 65 Ma. The corresponding thermal boundary conditions include zero out-flux at lateral boundaries, fixed temperatures at the upper surface and the bottom of the model (T 5 0 C at the surface and T 5 1330 C at the bottom of the lithosphere). ...
Lecture 4
... Basic concept: The outermost layer (LITHOSPHERE) is divided in a small number of “rigid” plates in relative motion one respect to the other Basic assumption: The generation of new plate material occurs by sea floor spreading. The new oceanic lithosphere form part of a rigid plate that may or may ...
... Basic concept: The outermost layer (LITHOSPHERE) is divided in a small number of “rigid” plates in relative motion one respect to the other Basic assumption: The generation of new plate material occurs by sea floor spreading. The new oceanic lithosphere form part of a rigid plate that may or may ...
Precambrian Research Geochemical and numerical constraints
... The distribution of TTGs into two geochemical groups was first noticed by Barker (1979) who divided TTGs into low- and highAl2 O3 groups (separated at 15% Al2 O3 and 70% silica) and suggested that the groups were produced by fractionation crystallization or different degree of partial melting. Arguin ...
... The distribution of TTGs into two geochemical groups was first noticed by Barker (1979) who divided TTGs into low- and highAl2 O3 groups (separated at 15% Al2 O3 and 70% silica) and suggested that the groups were produced by fractionation crystallization or different degree of partial melting. Arguin ...
Earth and Planetary Science Letters
... Volcanoes of the CKD are positioned ~ 170 km above the subducting Pacific Plate, in excess of the typical global value of ~ 100 km for arc volcanism. We present results of a combined geophysical and petrological study of the main volcanic center in the CKD, and argue for the presence of a second cont ...
... Volcanoes of the CKD are positioned ~ 170 km above the subducting Pacific Plate, in excess of the typical global value of ~ 100 km for arc volcanism. We present results of a combined geophysical and petrological study of the main volcanic center in the CKD, and argue for the presence of a second cont ...
Nature of the Vrancea seismic zone (Eastern Carpathians) – New
... and it is well-known for its strong intermediate depth earthquakes. Seismic tomography had revealed a high-velocity body beneath Vrancea and the Moesian platform that extends to a depth of at least 350 km and can be interpreted as descending lithosphere. The strong earthquakes occur within the north ...
... and it is well-known for its strong intermediate depth earthquakes. Seismic tomography had revealed a high-velocity body beneath Vrancea and the Moesian platform that extends to a depth of at least 350 km and can be interpreted as descending lithosphere. The strong earthquakes occur within the north ...
CONTINENTAL DRIFT LAB
... http://www.amnh.org/education/resources/rfl/pdf/dinos_plate_tectonics.pdf ...
... http://www.amnh.org/education/resources/rfl/pdf/dinos_plate_tectonics.pdf ...
Module 2_Excel - Scholar Commons
... The damage done by the iceberg was below water level along the ship’s hull and occurred so far beneath the surface of the ocean because the majority of the mass of any iceberg actually lies beneath the ocean, hidden by the waves. This is the result of buoyancy and isostasy, which also both turn out ...
... The damage done by the iceberg was below water level along the ship’s hull and occurred so far beneath the surface of the ocean because the majority of the mass of any iceberg actually lies beneath the ocean, hidden by the waves. This is the result of buoyancy and isostasy, which also both turn out ...
A case for drilling the Dufek layered mafic intrusion, Antarctica
... intrusion (and associated volcanic rocks) and those for the hotspots with which the intrusion has been linked. Chilled margins of FMP dikes and sills near the Dufek intrusion, have primitive mantle normalized trace element abundance patterns nearly identical to those of Bushveld parental magmas and ...
... intrusion (and associated volcanic rocks) and those for the hotspots with which the intrusion has been linked. Chilled margins of FMP dikes and sills near the Dufek intrusion, have primitive mantle normalized trace element abundance patterns nearly identical to those of Bushveld parental magmas and ...
Unit Objectives
... Explain what elastic rebound is and how it causes earthquakes Differentiate among the different types of seismic waves Use lag time and triangulation to locate the epicenter of an earthquake Describe what a tsunami is and how one is created Describe the distribution of the world’s earthquakes and th ...
... Explain what elastic rebound is and how it causes earthquakes Differentiate among the different types of seismic waves Use lag time and triangulation to locate the epicenter of an earthquake Describe what a tsunami is and how one is created Describe the distribution of the world’s earthquakes and th ...
Relation Between Volcanism, Tectonism, and Hydrothermal Activity
... Early studies focused on hydrothermal systems on the fast-spreading East Pacific Rise, where shallow magma lenses beneath the ridge crest provide heat to drive convection of seawater through the oceanic crust. Ten years later, studies of the slow-spreading Mid-Atlantic Ridge revealed much larger min ...
... Early studies focused on hydrothermal systems on the fast-spreading East Pacific Rise, where shallow magma lenses beneath the ridge crest provide heat to drive convection of seawater through the oceanic crust. Ten years later, studies of the slow-spreading Mid-Atlantic Ridge revealed much larger min ...
Plate tectonics
Plate tectonics (from the Late Latin tectonicus, from the Greek: τεκτονικός ""pertaining to building"") is a scientific theory that describes the large-scale motion of Earth's lithosphere. This theoretical model builds on the concept of continental drift which was developed during the first few decades of the 20th century. The geoscientific community accepted the theory after the concepts of seafloor spreading were later developed in the late 1950s and early 1960s.The lithosphere, which is the rigid outermost shell of a planet (on Earth, the crust and upper mantle), is broken up into tectonic plates. On Earth, there are seven or eight major plates (depending on how they are defined) and many minor plates. Where plates meet, their relative motion determines the type of boundary; convergent, divergent, or transform. Earthquakes, volcanic activity, mountain-building, and oceanic trench formation occur along these plate boundaries. The lateral relative movement of the plates typically varies from zero to 100 mm annually.Tectonic plates are composed of oceanic lithosphere and thicker continental lithosphere, each topped by its own kind of crust. Along convergent boundaries, subduction carries plates into the mantle; the material lost is roughly balanced by the formation of new (oceanic) crust along divergent margins by seafloor spreading. In this way, the total surface of the globe remains the same. This prediction of plate tectonics is also referred to as the conveyor belt principle. Earlier theories (that still have some supporters) propose gradual shrinking (contraction) or gradual expansion of the globe.Tectonic plates are able to move because the Earth's lithosphere has greater strength than the underlying asthenosphere. Lateral density variations in the mantle result in convection. Plate movement is thought to be driven by a combination of the motion of the seafloor away from the spreading ridge (due to variations in topography and density of the crust, which result in differences in gravitational forces) and drag, with downward suction, at the subduction zones. Another explanation lies in the different forces generated by the rotation of the globe and the tidal forces of the Sun and Moon. The relative importance of each of these factors and their relationship to each other is unclear, and still the subject of much debate.