The state of the upper mantle beneath southern Africa
... Fig. 3. Sv-velocity heterogeneity model for southern Africa. Depth-sections through the model are shown in (a) 150 and (b) 250 km depth. Each of the depth-sections has the velocity in the reference (Vref) model at that depth indicated beneath the map. The percentage of variation from the reference v ...
... Fig. 3. Sv-velocity heterogeneity model for southern Africa. Depth-sections through the model are shown in (a) 150 and (b) 250 km depth. Each of the depth-sections has the velocity in the reference (Vref) model at that depth indicated beneath the map. The percentage of variation from the reference v ...
Listric Thrust Faulting in the Laramide Front of North
... vanian faults generated during the Ancestral Rocky Mountain orogeny were reactivated in numerous areas in the southern Rockies [e.g. Tweto, 1975; and Stone, 1986). Marshak et al. [2000] postulated that Ancestral Rockies and Laramide faults resulted from tectonic inversion of a Precambrian normal fau ...
... vanian faults generated during the Ancestral Rocky Mountain orogeny were reactivated in numerous areas in the southern Rockies [e.g. Tweto, 1975; and Stone, 1986). Marshak et al. [2000] postulated that Ancestral Rockies and Laramide faults resulted from tectonic inversion of a Precambrian normal fau ...
Lateral structural variations of Poisson`s ratio and attenuation
... The velocity values obtained for all of the 17 regions seen in Fig. 4 are displayed on the lefthand side, the attenuation coefficients can be seen on the right, and the velocity and attenuation coefficient values calculated for the whole region are shown at the very bottom. Poisson’s values can be o ...
... The velocity values obtained for all of the 17 regions seen in Fig. 4 are displayed on the lefthand side, the attenuation coefficients can be seen on the right, and the velocity and attenuation coefficient values calculated for the whole region are shown at the very bottom. Poisson’s values can be o ...
Thematic Article Oceanic crust and Moho of the Pacific Plate in the
... Plateau, we have analyzed industry-standard two-dimensional multichannel seismic reflection data. To obtain improved velocity models, phase information of seismic signals was used for velocity analysis and velocity models for oceanic crust above Moho were determined. We apply this velocity analysis ...
... Plateau, we have analyzed industry-standard two-dimensional multichannel seismic reflection data. To obtain improved velocity models, phase information of seismic signals was used for velocity analysis and velocity models for oceanic crust above Moho were determined. We apply this velocity analysis ...
34. The Geological and Geophysical Setting near Site 462
... the drilling results. The interval from the chert reflector to the top of the sill complex (interval 2 in Table 1) was observed on four sonobuoys, and has an average interval velocity of 3.5 km/s and a calculated thickness of 0.452 km. Drilling results at Site 462 (see Site Summary, this volume) yie ...
... the drilling results. The interval from the chert reflector to the top of the sill complex (interval 2 in Table 1) was observed on four sonobuoys, and has an average interval velocity of 3.5 km/s and a calculated thickness of 0.452 km. Drilling results at Site 462 (see Site Summary, this volume) yie ...
Tomographic evidence for hydrated oceanic crust of the Pacific slab
... number of arrival-time data of 311,280 for P waves and 267,828 for S waves from 14,032 earthquakes that occurred in the period from 2001 to 2006. Arrival-time data were taken from the catalogue of the Japan Meteorological Agency (JMA). The distance between earthquake pairs was limited to 10 km, yiel ...
... number of arrival-time data of 311,280 for P waves and 267,828 for S waves from 14,032 earthquakes that occurred in the period from 2001 to 2006. Arrival-time data were taken from the catalogue of the Japan Meteorological Agency (JMA). The distance between earthquake pairs was limited to 10 km, yiel ...
SeiSmological grand challengeS in UnderStanding earth`S
... societally important applications of the discipline and to address the 10 Grand Challenge research questions requires sustained and expanded support of seismic data acquisition, archival, and distribution facilities. Global and regional seismological networks with a commitment to long-term operation ...
... societally important applications of the discipline and to address the 10 Grand Challenge research questions requires sustained and expanded support of seismic data acquisition, archival, and distribution facilities. Global and regional seismological networks with a commitment to long-term operation ...
NON DESTRUCTIVE TEST METHODS OF STONE AND ROCK
... Other kinds of waves travel along surfaces of discontinuities between materials. These waves are called surface waves. The most conspicuous discontinuity is that of the free surface between stone material and air. The waves, which travel along the free surface, may also be of two different kinds. On ...
... Other kinds of waves travel along surfaces of discontinuities between materials. These waves are called surface waves. The most conspicuous discontinuity is that of the free surface between stone material and air. The waves, which travel along the free surface, may also be of two different kinds. On ...
Locating hydrothermal acoustic sources at Old Faithful Geyser using
... the replica vector since we expect to retrieve a local source for which the geophone array is located at one or two wavelengths away from the source. In this case, the separation between Rayleigh waves and body waves is not effective and wave propagation can be modelled by a velocity c that depends ...
... the replica vector since we expect to retrieve a local source for which the geophone array is located at one or two wavelengths away from the source. In this case, the separation between Rayleigh waves and body waves is not effective and wave propagation can be modelled by a velocity c that depends ...
Multiscale seismic reflectivity of shallow thermoclines
... Broad-band acoustic backscatter measurements are a very promising technique and have permitted spectacular advances, for instance in the study of non-linear internal waves and their role as a source of turbulent mixing and entrainment on the seasonal thermoclines of shelf seas [Moum et al., 2003]. T ...
... Broad-band acoustic backscatter measurements are a very promising technique and have permitted spectacular advances, for instance in the study of non-linear internal waves and their role as a source of turbulent mixing and entrainment on the seasonal thermoclines of shelf seas [Moum et al., 2003]. T ...
Seismic crustal structure between the Transylvanian
... intermediate depths, which is concentrated in the Vrancea area of the southeastern Carpathian bend (Fig. 1; Fuchs et al., 1979; Oncescu et al., 1998). While the shallow seismic activity scatters widely and has moderate magnitudes (Mw b 5.6), the epicentral region of the intermediate depth seismicity ...
... intermediate depths, which is concentrated in the Vrancea area of the southeastern Carpathian bend (Fig. 1; Fuchs et al., 1979; Oncescu et al., 1998). While the shallow seismic activity scatters widely and has moderate magnitudes (Mw b 5.6), the epicentral region of the intermediate depth seismicity ...
Getting something for nothing: noise attenuation in an aliased world
... To help visualize why radial trace domain AGC is so effective, we show in Figure A1 the raw trace gather from Figure 1, transformed to the radial trace dip domain using a narrow velocity range centered on the velocity of the very strong surface wave. In that domain, traces are parallel to the cohere ...
... To help visualize why radial trace domain AGC is so effective, we show in Figure A1 the raw trace gather from Figure 1, transformed to the radial trace dip domain using a narrow velocity range centered on the velocity of the very strong surface wave. In that domain, traces are parallel to the cohere ...
Continental crust under compression: A seismic refraction study of
... coverage of both flanks of the Southern Alps, but instruments positioned near the east and west coast did not record many useful offshore data from across the 150 km wide land section of Transect 1. Seismic coverage of the crust beneath central South Island was provided mostly by 16 large chemical e ...
... coverage of both flanks of the Southern Alps, but instruments positioned near the east and west coast did not record many useful offshore data from across the 150 km wide land section of Transect 1. Seismic coverage of the crust beneath central South Island was provided mostly by 16 large chemical e ...
letters - Institut de Physique du Globe de Paris
... the Moho reflections is complex, but it is generally positive, similar to the seabed reflections, requiring a positive velocity contrast. The existence of near-vertical incidence reflections from the Moho means that the crust–mantle boundary is sharp compared to the wavelength (300 m) of the seismic ...
... the Moho reflections is complex, but it is generally positive, similar to the seabed reflections, requiring a positive velocity contrast. The existence of near-vertical incidence reflections from the Moho means that the crust–mantle boundary is sharp compared to the wavelength (300 m) of the seismic ...
application of micro-seismic methods to geothermal exploration
... 2.2.3 Magnitude and event location There are many packages used for event location and magnitude determinations. However, most of them are based on the HYPO71 package [Lee and Lahr, 1975]. The P and S arrival times read from the sections are entered manually into the HYPO71 (or hypoinverse) for prel ...
... 2.2.3 Magnitude and event location There are many packages used for event location and magnitude determinations. However, most of them are based on the HYPO71 package [Lee and Lahr, 1975]. The P and S arrival times read from the sections are entered manually into the HYPO71 (or hypoinverse) for prel ...
Crustal structure across the post-spreading - Archimer
... branches of OBS05 (Fig. 4a). The Pg phases (green and blue) appear within the -24 to 24 km offset. The Pn phases (pink) can be followed continuously on both sides of OBS05 within the -24 to -56 km offset and the 24 to 50 km offset. The PmP phase (yellow), clearly followed beneath the Pg arrivals wit ...
... branches of OBS05 (Fig. 4a). The Pg phases (green and blue) appear within the -24 to 24 km offset. The Pn phases (pink) can be followed continuously on both sides of OBS05 within the -24 to -56 km offset and the 24 to 50 km offset. The PmP phase (yellow), clearly followed beneath the Pg arrivals wit ...
Exploring the seismic expression of fault zones in 3D
... are exemplified in Fig. 1. While some parts of the data appear to show discrete offsets across narrow zones where seismic amplitude is greatly reduced, other levels show broader areas of amplitude reduction. This could represent zones of more broadly dispersed deformation, such as are found in fault ...
... are exemplified in Fig. 1. While some parts of the data appear to show discrete offsets across narrow zones where seismic amplitude is greatly reduced, other levels show broader areas of amplitude reduction. This could represent zones of more broadly dispersed deformation, such as are found in fault ...
Acquisition of the Blackfoot broad-band seismic survey
... The fourth line consisted of 200 Mark Products L-4A 2 Hz vertical geophones. These geophones were put into garbage bags and set on a base plate which was planted in holes 40 cm deep. The bagged geophones were then covered over with dirt. At a meter from the fourth line, a shorter line of 60 L-4A 2 H ...
... The fourth line consisted of 200 Mark Products L-4A 2 Hz vertical geophones. These geophones were put into garbage bags and set on a base plate which was planted in holes 40 cm deep. The bagged geophones were then covered over with dirt. At a meter from the fourth line, a shorter line of 60 L-4A 2 H ...
From seismic noise to ocean wave parameters
... data over the entire year. Schimmel et al. [2011] also independently verified the location of the sources with the measured polarization directions of Rayleigh waves. This model may thus be used to guide the interpretation of seismic noise records, especially for estimating the locations of the nois ...
... data over the entire year. Schimmel et al. [2011] also independently verified the location of the sources with the measured polarization directions of Rayleigh waves. This model may thus be used to guide the interpretation of seismic noise records, especially for estimating the locations of the nois ...
This article appeared in a journal published by Elsevier. The
... structure, the Las Cañadas edifice (Marti et al., 1994) (Fig. 1). The volcanic evolution of Tenerife comprises both constructive and destructive phases including vertical and lateral collapses on the order of several km3 (Marti et al., 1997). At least three vertical collapses resulted in the formatio ...
... structure, the Las Cañadas edifice (Marti et al., 1994) (Fig. 1). The volcanic evolution of Tenerife comprises both constructive and destructive phases including vertical and lateral collapses on the order of several km3 (Marti et al., 1997). At least three vertical collapses resulted in the formatio ...
Low seismic-wave speeds and enhanced fluid
... the line 2 structure, using the surface trace of the Alpine fault as a reference line, there is striking correspondence, in both depth and extent of the low-speed zone, to the core of the low-resistivity region (Fig. 4). Dipping reflectivity that defines the subsurface extension of the Alpine fault ...
... the line 2 structure, using the surface trace of the Alpine fault as a reference line, there is striking correspondence, in both depth and extent of the low-speed zone, to the core of the low-resistivity region (Fig. 4). Dipping reflectivity that defines the subsurface extension of the Alpine fault ...
Ocean wave sources of seismic noise
... associated with peaks for which the phase speeds are less than 1.2 times U10, the wind speed at 10 m height. That second condition corresponds, in deep water, to g/(2p f ) < 1.2U10. This association of spectral components with a given peak is done using an watershed‐type algorithm: all components th ...
... associated with peaks for which the phase speeds are less than 1.2 times U10, the wind speed at 10 m height. That second condition corresponds, in deep water, to g/(2p f ) < 1.2U10. This association of spectral components with a given peak is done using an watershed‐type algorithm: all components th ...
A fault caught in the act of burping
... to fluid flow and, at times, preferential pathways for flow. Both behaviors are invoked in the petroleum industry to explain how hydrocarbons move (Hooper, 1991) from the location at which they are generated (e.g., by flowing along faults) into fault-bounded reservoirs (Holland et al., 1990) where t ...
... to fluid flow and, at times, preferential pathways for flow. Both behaviors are invoked in the petroleum industry to explain how hydrocarbons move (Hooper, 1991) from the location at which they are generated (e.g., by flowing along faults) into fault-bounded reservoirs (Holland et al., 1990) where t ...
Reflection seismology
Reflection seismology (or seismic reflection) is a method of exploration geophysics that uses the principles of seismology to estimate the properties of the Earth's subsurface from reflected seismic waves. The method requires a controlled seismic source of energy, such as dynamite/Tovex, a specialized air gun or a seismic vibrator, commonly known by the trademark name Vibroseis. Reflection seismology is similar to sonar and echolocation. This article is about surface seismic surveys; for vertical seismic profiles, see VSP.