Geology: Fluids in the lower crust following Mendocino triple
... Geodynamic and plate tectonic models for the Mendocino triple junction, a fault-fault-trench triple junction in northwestern California, predict a slab-free zone south of the triple junction in which asthenospheric mantle upwells to the base of the crust. A variety of geological and geophysical data ...
... Geodynamic and plate tectonic models for the Mendocino triple junction, a fault-fault-trench triple junction in northwestern California, predict a slab-free zone south of the triple junction in which asthenospheric mantle upwells to the base of the crust. A variety of geological and geophysical data ...
Seismic structure of the northern end of the Ryukyu Trench... southeast of Kyushu, Japan
... the southwestern end of the profile. Only the region shallower than 5 km could be determined by the first arrival tomographic inversion. Because of very few first arrivals propagating in the deeper part with thick and low velocity, we mainly conducted forward modeling using later arrivals both of re ...
... the southwestern end of the profile. Only the region shallower than 5 km could be determined by the first arrival tomographic inversion. Because of very few first arrivals propagating in the deeper part with thick and low velocity, we mainly conducted forward modeling using later arrivals both of re ...
Section 19.1 Forces within Earth
... What happens to the waves after they go into a new material? These waves change speed and direction when they encounter different materials. ...
... What happens to the waves after they go into a new material? These waves change speed and direction when they encounter different materials. ...
Chapter 8 Earthquakes Vibrations of the Earth caused by the
... Needs much more study. It was accidentally discovered that earthquakes can be triggered by pumping fluids into fault zones. Water acts as a lubricant, allowing faults to move. May be able to reduce stress on major faults by triggering small earthquakes using fluid injection. The best defense current ...
... Needs much more study. It was accidentally discovered that earthquakes can be triggered by pumping fluids into fault zones. Water acts as a lubricant, allowing faults to move. May be able to reduce stress on major faults by triggering small earthquakes using fluid injection. The best defense current ...
1 Crustal Structure, Isostasy, and Rheology Introduction This lecture
... crust is provided. The emphasis is on layer thickness and densities and there is little discussion of composition. The second and third topics are the vertical and horizontal force balances due to variation in crustal thickness. The vertical force balance, isostasy, provides a remarkably accurate de ...
... crust is provided. The emphasis is on layer thickness and densities and there is little discussion of composition. The second and third topics are the vertical and horizontal force balances due to variation in crustal thickness. The vertical force balance, isostasy, provides a remarkably accurate de ...
bokelmannAbstract_5p..
... In a previous study we found that the Canadian shield lithosphere consists of two anisotropic layers with the shallower one having a subvertical and the deeper having a subhorizontal foliation plane (Bokelmann and Silver, 2000). These foliation plane orientations are indicative of a) a vertically co ...
... In a previous study we found that the Canadian shield lithosphere consists of two anisotropic layers with the shallower one having a subvertical and the deeper having a subhorizontal foliation plane (Bokelmann and Silver, 2000). These foliation plane orientations are indicative of a) a vertically co ...
A mantle plume below the Eifel volcanic ¢elds, Germany
... their magma supply from much more voluminous up£ows, rising from greater depth in the mantle. The melt production in the plumes is controlled by variations in buoyancy £ux, volatile content, thickness of the overlying lithosphere and excess temperature of the plume [4,25,26,29]. Subtle differences i ...
... their magma supply from much more voluminous up£ows, rising from greater depth in the mantle. The melt production in the plumes is controlled by variations in buoyancy £ux, volatile content, thickness of the overlying lithosphere and excess temperature of the plume [4,25,26,29]. Subtle differences i ...
univERsity oF copEnhAGEn
... includes random velocity fluctuations with horizontal scale of 5 –10 km, thickness less than 5 km, and standard deviation of 2% from background velocity. It agrees with an upper mantle model in which an inhomogeneous low-velocity scattering layer at depths of between 100 and 185 km may contain small ...
... includes random velocity fluctuations with horizontal scale of 5 –10 km, thickness less than 5 km, and standard deviation of 2% from background velocity. It agrees with an upper mantle model in which an inhomogeneous low-velocity scattering layer at depths of between 100 and 185 km may contain small ...
Earth Structure
... Further, we note that the ray parameter ‘p’ equals the ‘1/cb’ at the maximum penetration depth ‘z’, for sin i = 1 for horizontal rays, with ‘cb’ as the phase velocity at the bottom (turning point) of the ray. Assuming the following restrictions, 1. all layers are parallel (= no horizontal velocity g ...
... Further, we note that the ray parameter ‘p’ equals the ‘1/cb’ at the maximum penetration depth ‘z’, for sin i = 1 for horizontal rays, with ‘cb’ as the phase velocity at the bottom (turning point) of the ray. Assuming the following restrictions, 1. all layers are parallel (= no horizontal velocity g ...
Seismic wave speed structure of the Ontong
... speed geometry than ray based methods (Hung et al., 2004), reducing smearing, leading to higher amplitude and more constrained anomalies (Becker, 2012). While there has been discussions about the effectiveness of the finite frequency method in the applications to real data (Van Der Hilst and Maarten, ...
... speed geometry than ray based methods (Hung et al., 2004), reducing smearing, leading to higher amplitude and more constrained anomalies (Becker, 2012). While there has been discussions about the effectiveness of the finite frequency method in the applications to real data (Van Der Hilst and Maarten, ...
Characteristic and Uncharacteristic Earthquakes as Possible
... In general both plates and plate boundaries move with respect to the deep mantle For example, assume Africa were not moving with respect to the deep mantle. If so, as lithosphere is added by spreading at the Mid-Atlantic ridge, both the ridge and South America move westward relative to the mantle. C ...
... In general both plates and plate boundaries move with respect to the deep mantle For example, assume Africa were not moving with respect to the deep mantle. If so, as lithosphere is added by spreading at the Mid-Atlantic ridge, both the ridge and South America move westward relative to the mantle. C ...
On the origin of the asthenosphere
... 2006) and will not be repeated here. In this paper, I will focus on seismological aspects. Early surface wave studies showed that (i) there is a low velocity zone in the oceanic upper mantle at the depth range of ~50–200 km (depending on the age of the ocean floor) where the velocity drop from the li ...
... 2006) and will not be repeated here. In this paper, I will focus on seismological aspects. Early surface wave studies showed that (i) there is a low velocity zone in the oceanic upper mantle at the depth range of ~50–200 km (depending on the age of the ocean floor) where the velocity drop from the li ...
Imaging the Gutenberg Seismic Discontinuity beneath the Oceanic
... 660 km discontinuities are from phase changes in the mineral olivine. Other discontinuities like the one found at the mantle-outer core boundary is from the transition of rock to liquid metal. However, there are several discontinuities other than those listed above that do not necessarily have a cle ...
... 660 km discontinuities are from phase changes in the mineral olivine. Other discontinuities like the one found at the mantle-outer core boundary is from the transition of rock to liquid metal. However, there are several discontinuities other than those listed above that do not necessarily have a cle ...
Seismic waves - opotikicollegeearthscience
... through air, but may travel at 5,000 ms-1 in granite. Because of their speed, they are the first waves to be recorded by a seismograph during an earthquake. • They differ from S-waves in that they spread through a material by alternately compressing and expanding the medium, where particle motion is ...
... through air, but may travel at 5,000 ms-1 in granite. Because of their speed, they are the first waves to be recorded by a seismograph during an earthquake. • They differ from S-waves in that they spread through a material by alternately compressing and expanding the medium, where particle motion is ...
Earthquake
... – Stress: a push or pull on an object (stress = force/area) – Strain: a change in shape or size (deformation) of an object (strain = change in length/original length) – The process is known as elastic rebound theory Elastic strain: strain that is recoverable ...
... – Stress: a push or pull on an object (stress = force/area) – Strain: a change in shape or size (deformation) of an object (strain = change in length/original length) – The process is known as elastic rebound theory Elastic strain: strain that is recoverable ...
The Lithosphere – Asthenosphere System: Nature of the Tectonic
... different types of observations. Using a massive dataset of surface wave dispersions in a broad frequency range (15300s), we have developed a 3D anisotropic tomographic model of the upper mantle at the global scale. It is used to derive maps of LAB from the resolved elastic parameters. We investigat ...
... different types of observations. Using a massive dataset of surface wave dispersions in a broad frequency range (15300s), we have developed a 3D anisotropic tomographic model of the upper mantle at the global scale. It is used to derive maps of LAB from the resolved elastic parameters. We investigat ...
Section 19.1 Forces Within Earth
... occur along narrow seismic belts that separate large regions with little or no seismic activity. •The locations of most earthquakes correspond closely with tectonic plate boundaries. ...
... occur along narrow seismic belts that separate large regions with little or no seismic activity. •The locations of most earthquakes correspond closely with tectonic plate boundaries. ...
Teleseismic surface wave tomography in the western US using the
... deviation of the Gaussian fit at each node and this information can be plotted as a resolution map. Examples of resolution maps at 12 and 33 sec period are presented in Fig. S1. In the multiple-plane-wave tomography, we do not estimate resolution directly. We infer it indirectly based on the similar ...
... deviation of the Gaussian fit at each node and this information can be plotted as a resolution map. Examples of resolution maps at 12 and 33 sec period are presented in Fig. S1. In the multiple-plane-wave tomography, we do not estimate resolution directly. We infer it indirectly based on the similar ...
Geofizikai közlemények - 45. köt. 4. sz. (2011. december)
... Based on the both, the seismic and the gravity modelling, two types of crust can be defined: the Dinaridic and the Pannonian (Fig. 4). The Dinaridic crust is comprised of two parts, the lower and the upper crust, whereas the Pannonian crust is virtually unified. The Dinaridic upper crust is characte ...
... Based on the both, the seismic and the gravity modelling, two types of crust can be defined: the Dinaridic and the Pannonian (Fig. 4). The Dinaridic crust is comprised of two parts, the lower and the upper crust, whereas the Pannonian crust is virtually unified. The Dinaridic upper crust is characte ...
PDF (Chapter 3. The Crust and Upper Mantle)
... large fraction of the terrestrial inventory of many elements. In this and the next chapter I discuss each of the major subdivisions, starting with the crust and ending with the inner core. ...
... large fraction of the terrestrial inventory of many elements. In this and the next chapter I discuss each of the major subdivisions, starting with the crust and ending with the inner core. ...
Plate Tectonics Notes # 2
... lithosphere. In between the crust and the rigid mantle is a region called the MOHO. This represents a boundary where the rocks _______________ rapidly in INCREASE density. Even though there are density differences the crust and mantle are considered a single part (THE LITHOSPHERE) and move together! ...
... lithosphere. In between the crust and the rigid mantle is a region called the MOHO. This represents a boundary where the rocks _______________ rapidly in INCREASE density. Even though there are density differences the crust and mantle are considered a single part (THE LITHOSPHERE) and move together! ...
A low velocity belt beneath northern and eastern Tibetan Plateau
... that the crust and the lithosphere in the northern TP are hot and deformable. Three mechanisms have been proposed to explain the source of heat: convective removal [Molnar et al., 1993]; subduction-induced upwelling [Tilman and Ni, 2003], and strain heating [McNamara et al., 1994]. [19] Since the co ...
... that the crust and the lithosphere in the northern TP are hot and deformable. Three mechanisms have been proposed to explain the source of heat: convective removal [Molnar et al., 1993]; subduction-induced upwelling [Tilman and Ni, 2003], and strain heating [McNamara et al., 1994]. [19] Since the co ...
Seismic Waves - Faculty Web Pages
... speed). Part of the energy carried by the incident wave is transmitted through the material and part is reflected back into the medium that contained the incident wave. In seismology, reflections are used to prospect for petroleum and investigate Earth's internal structure. The amplitude of the ...
... speed). Part of the energy carried by the incident wave is transmitted through the material and part is reflected back into the medium that contained the incident wave. In seismology, reflections are used to prospect for petroleum and investigate Earth's internal structure. The amplitude of the ...