Crustal Velocity Variations in Taiwan Revealed by Active-Source Seismic Observations

2017 ◽  
pp. 35-59
Author(s):  
Yu-Pin Lin
Keyword(s):  
Crustal Velocity ◽  
Active Source ◽  
Velocity Variations

An analysis of the crust–mantle boundary in Hudson Bay from gravity and seismic observations

1968 ◽  
Vol 5 (5) ◽  
pp. 1297-1303 ◽  
Author(s):  
J. R. Weber ◽  
A. K. Goodacre
Keyword(s):  
Gravity Anomaly ◽  
Gravity Anomalies ◽  
Gravitational Effect ◽  
Compressional Wave ◽  
Seismic Survey ◽  
Hudson Bay ◽  
Mantle Boundary ◽  
Crustal Velocity ◽  
Velocity Variations ◽  
Crustal Density

A study of the results of the gravity and seismic surveys in Hudson Bay in 1965 has shown that the gravitational effect of a two-layer model based on the seismically determined depths has no correlation with the observed gravity anomalies. On the profile from Churchill to Povungnituk the gravity and seismic observations can be reconciled by postulating lateral variations of the acoustic compressional wave velocity within the crust. A crustal model has been calculated—using the same time-terms and the same mean crustal velocity—whose gravitational effect fits the observed gravity. The velocity varies from 6.15 to 6.56 km/s and the postulated depths are almost entirely within the confidence limits of the original model.In order to test the hypothesis, the postulated velocity variations have been compared with the lower refractor velocities of the shallow seismic survey, based on the assumption that the crustal velocities ought to be systematically higher than the crystalline surface velocities and that there may be a correlation between variations in crustal and surface velocities. The test is inconclusive because bottom refractor velocities are higher than crustal velocities in two areas where volcanic flows and high-velocity sediments may be present.The case of linearly related velocity (V) and density (ρ) variations has been analyzed and it is shown that the gravitational effect of the crust–mantle boundary undulations may be completely masked or even overbalanced by density changes in the crust if [Formula: see text]. The crust can be characterized by having dominant velocity variations (in which case the gravity anomaly reflects the undulations of the crust–mantle boundary) or dominant density variations (in which case the gravity anomaly inversely reflects the crust–mantle boundary undulations) depending on the relationship between average crustal density and average crustal velocity.

Crustal velocity structure of Cathaysia Block from an active-source seismic profile between Wanzai and Hui'an in SE China

2021 ◽  
Vol 811 ◽  
pp. 228874
Author(s):  
Jiyan Lin ◽  
Tao Xu ◽  
Huiteng Cai ◽  
Qingtian Lü ◽  
Zhiming Bai ◽  
...  
Keyword(s):  
Velocity Structure ◽  
Seismic Profile ◽  
Crustal Velocity ◽  
Crustal Velocity Structure ◽  
Active Source ◽  
Cathaysia Block ◽  
Se China

Tomographic reconstruction of upper crustal velocity variations in the Arunta Block, central Australia

1990 ◽  
Vol 173 (1-4) ◽  
pp. 63-72 ◽  
Author(s):  
S.A. Greenhalgh ◽  
S. Sugiharto ◽  
C. Wright ◽  
B.R. Goleby
Keyword(s):  
Tomographic Reconstruction ◽  
Crustal Velocity ◽  
Central Australia ◽  
Velocity Variations

A baseline for upper crustal velocity variations along the East Pacific Rise at 13°N

1995 ◽  
Vol 100 (B4) ◽  
pp. 6143-6161 ◽  
Author(s):  
Mary E. Kappus ◽  
Alistair J. Harding ◽  
John A. Orcutt
Keyword(s):  
East Pacific Rise ◽  
Crustal Velocity ◽  
East Pacific ◽  
Velocity Variations
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