The lithosphere and asthenosphere of the Iceland hotspot from
... not find any Moho reflections from what could be interpreted as a shallow boundary of the crust and mantle (BCM), reflections were observed from a thin, higher-velocity layer (7.8 km s−1 ) at about 30 km depth. In a later analysis by Menke et al. (1996), these RRISP data were found to be consistent ...
... not find any Moho reflections from what could be interpreted as a shallow boundary of the crust and mantle (BCM), reflections were observed from a thin, higher-velocity layer (7.8 km s−1 ) at about 30 km depth. In a later analysis by Menke et al. (1996), these RRISP data were found to be consistent ...
Three dimensional shear wave velocity structure of crust and upper
... Nolet (1990) presents a new method for nonlinear waveform inversion, partitioned waveform inversion (PWI). Shear wave velocity variations in the upper mantle beneath central Europe were studied by using PWI method (Zielhuis, Nolet, 1994). The resulting 3-D model can accurately predict the real veloc ...
... Nolet (1990) presents a new method for nonlinear waveform inversion, partitioned waveform inversion (PWI). Shear wave velocity variations in the upper mantle beneath central Europe were studied by using PWI method (Zielhuis, Nolet, 1994). The resulting 3-D model can accurately predict the real veloc ...
Regional phases in continental and oceanic environments
... the frames at 30 and 44 s) and transmission into the mantle occurs in each of the pre-critical reflections, helping to enhance the Sn field. The S waves in the oceanic crust are linked to reverberations of P waves in the ocean. These P multiples build a strong wave train following Sn that extends ne ...
... the frames at 30 and 44 s) and transmission into the mantle occurs in each of the pre-critical reflections, helping to enhance the Sn field. The S waves in the oceanic crust are linked to reverberations of P waves in the ocean. These P multiples build a strong wave train following Sn that extends ne ...
Science Article PDF - Geological Society of America
... assume a flat Earth: At 100 km depth they are ~0.15 km/s faster than in a spherical Earth. Bottom: Record sections from SP43, SP37, and SP49 are plotted beneath the shot location with calculated traveltime curves from the model superimposed in red. The blue circles indicate the crossover where Pn be ...
... assume a flat Earth: At 100 km depth they are ~0.15 km/s faster than in a spherical Earth. Bottom: Record sections from SP43, SP37, and SP49 are plotted beneath the shot location with calculated traveltime curves from the model superimposed in red. The blue circles indicate the crossover where Pn be ...
Structure of the Earth`s Crust in Fennoscandia as Revealed from
... reaching 56 km under the northeastern end of the profile. The crust can be divided into upper crust (P-wave velocity 5.6-6.45 km/s), middle crust (velocity of 6.6-6.75 km/s) and lower crust with velocities of 6.95 - 7.45 km/s. At the bottom of the lower crust a layer with a velocity higher than 7.35 ...
... reaching 56 km under the northeastern end of the profile. The crust can be divided into upper crust (P-wave velocity 5.6-6.45 km/s), middle crust (velocity of 6.6-6.75 km/s) and lower crust with velocities of 6.95 - 7.45 km/s. At the bottom of the lower crust a layer with a velocity higher than 7.35 ...
deep crustal structure and estimation of moho in the lhasa terrane of
... Frequency attributes of the INDEPTH deep seismic profiles (Figures 2-5) of the southern BNS under the Lhasa block are estimated and shown in Figures 8-11. In each profile, the horizontal axis indicates the distance from southern end and vertical axis indicates the two way travel time in second. In t ...
... Frequency attributes of the INDEPTH deep seismic profiles (Figures 2-5) of the southern BNS under the Lhasa block are estimated and shown in Figures 8-11. In each profile, the horizontal axis indicates the distance from southern end and vertical axis indicates the two way travel time in second. In t ...
Mantle-driven deformation of orogenic zones and clutch tectonics
... travelling through anisotropic media is shearwave splitting, similar to optical birefringence, in which the incoming shear wave is split in two quasi-orthogonal waves that travel at different speeds (see reviews by Silver 1996; Savage 1999). The time lag between the two waves is controlled by the in ...
... travelling through anisotropic media is shearwave splitting, similar to optical birefringence, in which the incoming shear wave is split in two quasi-orthogonal waves that travel at different speeds (see reviews by Silver 1996; Savage 1999). The time lag between the two waves is controlled by the in ...
Nature of the Vrancea seismic zone (Eastern Carpathians) – New
... part of this high-velocity body, in a very limited seismogenic volume at intermediate depth (70–180 km). Several geodynamic models have been proposed for this area. They can be split into two main categories, in terms of the nature of the high-velocity anomaly, which may (a) be associated with desce ...
... part of this high-velocity body, in a very limited seismogenic volume at intermediate depth (70–180 km). Several geodynamic models have been proposed for this area. They can be split into two main categories, in terms of the nature of the high-velocity anomaly, which may (a) be associated with desce ...
analysis of deep Earth seismic waves
... ∆ (delta). It can be converted to an approximate distance in kilometers using 1 geocentric degree ' 111.2 km. Really the surface length of a geocentric degree varies with latitude and with the azimuth (bearing) from source to recording station. This variation is compensated using ellipticity correct ...
... ∆ (delta). It can be converted to an approximate distance in kilometers using 1 geocentric degree ' 111.2 km. Really the surface length of a geocentric degree varies with latitude and with the azimuth (bearing) from source to recording station. This variation is compensated using ellipticity correct ...
The Mantle and Creation of the Oceanic Crust The Mantle
... Mantle is heated both from within and below. ...
... Mantle is heated both from within and below. ...
Cascadia subduction slab heterogeneity revealed by three
... located in central Oregon and northern California, respectively (Figure 1a). The wide aperture Transportable Array allows us to image the western U.S. structure down to the transition zone across the continent. Two RF data sets were obtained from waveforms low-pass filtered at 0.1 and 0.2 Hz. In this ...
... located in central Oregon and northern California, respectively (Figure 1a). The wide aperture Transportable Array allows us to image the western U.S. structure down to the transition zone across the continent. Two RF data sets were obtained from waveforms low-pass filtered at 0.1 and 0.2 Hz. In this ...
Seismology (a very short indroduction)
... The asthenosphere exists between depths of 100200 km. It is the weakest part of the mantle. It is a solid over short time scales, but behaves like a fluid over millions of years. The asthenosphere decouples the lithosphere (tectonic plates) from the rest of the mantle. ...
... The asthenosphere exists between depths of 100200 km. It is the weakest part of the mantle. It is a solid over short time scales, but behaves like a fluid over millions of years. The asthenosphere decouples the lithosphere (tectonic plates) from the rest of the mantle. ...
The Southern Sierra Nevada Drip and the Mantle Wind Direction
... simplified analyses can provide a few basic constraints. The mantle anomaly can be viewed as a convective instability developing at the thermal boundary layer between the lithosphere and the asthenosphere. Zandt and Carrigan (1993) used thermal calculations and estimates of the local Rayleigh number ...
... simplified analyses can provide a few basic constraints. The mantle anomaly can be viewed as a convective instability developing at the thermal boundary layer between the lithosphere and the asthenosphere. Zandt and Carrigan (1993) used thermal calculations and estimates of the local Rayleigh number ...
STRUCTURE OF EARTH
... One way that mantle peridotites may melt is by plastic flow of large regions toward the surface (i.e., lower pressures). ...
... One way that mantle peridotites may melt is by plastic flow of large regions toward the surface (i.e., lower pressures). ...
Earthquakes
... The Richter Scale for measures the 'size' or 'strength' of an earthquake. This scale is quantitative and based on the amount of energy released by an earthquake. The energy of a quake is a function of both the amplitude and the duration of a single wave. The seismogram below shows waves with a wide ...
... The Richter Scale for measures the 'size' or 'strength' of an earthquake. This scale is quantitative and based on the amount of energy released by an earthquake. The energy of a quake is a function of both the amplitude and the duration of a single wave. The seismogram below shows waves with a wide ...
Structure of the crust and uppermost mantle beneath the western
... [11] In the second step, a Markov Chain Monte Carlo resampling of model space [Shapiro and Ritzwoller, 2002; Yang et al., 2008; G. D. Bensen et al., submitted manuscript, 2008] is performed to quantify the uncertainty in shear velocity versus depth. The Markov Chain Monte Carlo inversion executes a ...
... [11] In the second step, a Markov Chain Monte Carlo resampling of model space [Shapiro and Ritzwoller, 2002; Yang et al., 2008; G. D. Bensen et al., submitted manuscript, 2008] is performed to quantify the uncertainty in shear velocity versus depth. The Markov Chain Monte Carlo inversion executes a ...
Imaging the seismic lithosphere‐asthenosphere boundary of the
... images are made. The shaded points are the conversion points for S‐to‐p waves at 100 km depth, and the inverted blue triangles are the seismic stations. The black lines mark plate boundaries (trench or transform fault). The right‐hand panels show the respective S receiver function images along the p ...
... images are made. The shaded points are the conversion points for S‐to‐p waves at 100 km depth, and the inverted blue triangles are the seismic stations. The black lines mark plate boundaries (trench or transform fault). The right‐hand panels show the respective S receiver function images along the p ...
200 K higher than assumed in
... TAKE-AWAY MESSAGE Mantle potential temperatures at ~200 km depth are higher than between ~ 400-2800 km depth. This is the most significant & farreaching development in mantle petrology & geochemistry since Birch & Bullen established the non-adiabaticity (subadiabatic thermal gradient) of the mantle ...
... TAKE-AWAY MESSAGE Mantle potential temperatures at ~200 km depth are higher than between ~ 400-2800 km depth. This is the most significant & farreaching development in mantle petrology & geochemistry since Birch & Bullen established the non-adiabaticity (subadiabatic thermal gradient) of the mantle ...
A seismic refraction study of the Cocos plate offshore Nicaragua and
... 1. Steep subduction beneath Nicaragua leads to increased bending, faulting of downgoing Cocos plate. 2. Mantle of downgoing plate is serpentinized at the outer rise of the Middle American Trench. 3. Water is released from subducting slab mantle at 100 km depth, where serpentinite breaks down. 4. Wat ...
... 1. Steep subduction beneath Nicaragua leads to increased bending, faulting of downgoing Cocos plate. 2. Mantle of downgoing plate is serpentinized at the outer rise of the Middle American Trench. 3. Water is released from subducting slab mantle at 100 km depth, where serpentinite breaks down. 4. Wat ...
Tectonophysics_2009_Crustal and upper mantle velocity
... Simao, and Zhongdian etc (Fig. 2). The analysis of this phase reveals that the P-wave velocity varies rapidly in the deepest part of the crust (Yan et al., 1985; Hu et al., 1986; Kan et al., 1986; Lin et al., 1993). Vp changes rapidly to 7.8 km/s and even to a value of 8.0 km/s and exceptionally 8.2 ...
... Simao, and Zhongdian etc (Fig. 2). The analysis of this phase reveals that the P-wave velocity varies rapidly in the deepest part of the crust (Yan et al., 1985; Hu et al., 1986; Kan et al., 1986; Lin et al., 1993). Vp changes rapidly to 7.8 km/s and even to a value of 8.0 km/s and exceptionally 8.2 ...
Did deglaciation trigger intraplate seismicity in the New Madrid
... possibly the reason for increased seismicity in the area. Liu and Zoback (1997) proposed that the high rate of seismicity results from high ductile strain rates in the lower crust and upper mantle due to locally elevated heat flow. Stuart et al. (1997) suggested the existence of a weak subhorizontal ...
... possibly the reason for increased seismicity in the area. Liu and Zoback (1997) proposed that the high rate of seismicity results from high ductile strain rates in the lower crust and upper mantle due to locally elevated heat flow. Stuart et al. (1997) suggested the existence of a weak subhorizontal ...
Crustal structure of the ocean-island arc transition at the mid... (Bonin) arc margin Azusa Nishizawa , Kentaro Kaneda
... 213 are not clear. This may be due to lateral inhomogeneity of the Moho. There are several en-echelon volcanic chains trending in the NE-SW direction on the western margin of the IOA (Fig. 1(b)). High-velocity materials ascending at the bathymetric highs are needed to explain the observed travel tim ...
... 213 are not clear. This may be due to lateral inhomogeneity of the Moho. There are several en-echelon volcanic chains trending in the NE-SW direction on the western margin of the IOA (Fig. 1(b)). High-velocity materials ascending at the bathymetric highs are needed to explain the observed travel tim ...
P Tohoku earthquakes, off the Boso Peninsula, deduced
... Through this inversion, the root-mean-square (RMS) error of the first-arrival data was reduced from 1427 ms to 151 ms. Finally, we obtained the final crustal model by a for- ...
... Through this inversion, the root-mean-square (RMS) error of the first-arrival data was reduced from 1427 ms to 151 ms. Finally, we obtained the final crustal model by a for- ...
surface wave - Madison Local Schools
... • earthquake a movement or trembling of the ground that is caused by a sudden release of energy when rocks along a fault move • Earthquakes occur when rocks under stress suddenly shift along a fault. • A fault is a break in a body of rock along which one block moves relative to another. • The rocks ...
... • earthquake a movement or trembling of the ground that is caused by a sudden release of energy when rocks along a fault move • Earthquakes occur when rocks under stress suddenly shift along a fault. • A fault is a break in a body of rock along which one block moves relative to another. • The rocks ...