Worldwide investigation of the mantle Rayleigh-wave group velocities

1973 ◽  
Vol 63 (1) ◽  
pp. 271-281
Author(s):  
Harsh K. Gupta ◽  
Tetsuo Santô
Keyword(s):  
Rayleigh Wave ◽  
Velocity Dispersion ◽  
Group Velocity Dispersion ◽  
Great Circle ◽  
Wave Group ◽  
High Group ◽  
Period Range ◽  
Very High ◽  
Group Velocities ◽  
Existing Data

abstract An attempt to apply the crossing path technique to the division of the globe into similar regions of mantle Rayleigh-wave group-velocity dispersion characteristics failed because of the paucity of existing data (for about 80 great-circle paths). As a first step to achieve this goal, mantle Rayleigh-wave group velocities have been obtained for 31 new great-circle paths in the 80- to 240-sec period range. The data have been divided into four groups on the basis of dispersion behavior and compared with Dziewonski's (1971) results. An interesting finding has been the very high group velocities for the 6-MUN path, higher than any reported so far.

Rayleigh wave group velocities in central California

1968 ◽  
Vol 58 (3) ◽  
pp. 881-890
Author(s):  
D. J. Sutton
Keyword(s):  
Rayleigh Wave ◽  
Group Velocity ◽  
Sierra Nevada ◽  
Wave Dispersion ◽  
Wave Group ◽  
Period Range ◽  
Central California ◽  
Great Valley ◽  
Rayleigh Wave Dispersion ◽  
Group Velocities

abstract Experimentally determined Rayleigh-wave dispersion curves of group velocity are given for five paths from NTS to stations in the network operated by the Seismographic Station at U.C. Berkeley. Periods observed range from 4 to 14 seconds. Although, as expected, two different paths from NTS to the western edge of the Sierra Nevada resulted in similar curves, efforts to find empirical curves appropriate to the Great Valley and the Coast Ranges on the assumption of provinces with parallel boundaries were not successful. Estimates of group velocity across the Great Valley along the path NTS to BRK indicate velocities, in the period range 5–9 seconds, considerably lower than would be expected from crustal models so far suggested.

Rayleigh- and Love-wave dispersion up to 140-second-period range in the Indonesia-Philippine region

1975 ◽  
Vol 65 (2) ◽  
pp. 507-521
Author(s):  
Harsh K. Gupta ◽  
Kazuo Hamada
Keyword(s):  
Rayleigh Wave ◽  
Group Velocity ◽  
Love Wave ◽  
Active Regions ◽  
Wave Dispersion ◽  
Wave Group ◽  
Period Range ◽  
Moving Window Analysis ◽  
Love Wave Dispersion ◽  
Group Velocities

abstract Group velocities for Rayleigh waves extending to 140-sec-period range have been determined for 10 paths in the Indonesia-Philippine region using moving window analysis. The group velocities for five of these paths have been determined from the vertical as well as the longitudinal components and the values obtained from the two components tally with each other. It has also been possible to obtain Love-wave group velocities for three of these paths. On the basis of group-velocity values and regions covered, the observed Rayleigh-wave group-velocity data could be divided into three groups. The first group includes data for paths mostly confined to deep ocean and the observed data could be explained by standard oceanic models such as 8099. The second group includes data for paths lying partially within seismically active regions and models ARC-1 and ALRDG-9 fit with these data. The third group shows still lower group velocities for paths entirely confined to seismically active regions. The shear velocities inferred from Love-wave dispersion data are higher than those inferred from Rayleigh-wave data. In general, the group velocities varied greatly within small distances even in the longer period range, indicating strong lateral heterogeneities in the mantle.

Rayleigh wave group velocity dispersion in the North and South Atlantic oceans

1980 ◽  
Vol 70 (5) ◽  
pp. 1787-1809
Author(s):  
Douglas H. Christensen ◽  
Jeffrey K. Kimball ◽  
Frederick J. Mauk
Keyword(s):  
Rayleigh Wave ◽  
Velocity Dispersion ◽  
Group Velocity Dispersion ◽  
South Atlantic ◽  
Wave Group ◽  
Dispersion Characteristics ◽  
Sea Floor ◽  
The North ◽  
The Pacific ◽  
North And South

abstract Group velocity dispersion characteristics of fundamental mode Rayleigh waves (T = 20 to 100 sec) in the North and South Atlantic oceans have been determined from moving window analyses of seismograms. The “mixed path” velocity data combined with oceanic age information for the North and South Atlantic were inverted to yield “pure path” dispersion characteristics for four sea-floor age divisions in the North Atlantic (0 to 23 m.y., 23 to 63 m.y., 63 to 100 m.y., and older than 100 m.y.), for three sea-floor age divisions in the South Atlantic (0 to 23 m.y., 23 to 63 m.y., and older than 63 m.y.), and for one nonoceanic division. Rayleigh wave group velocities were found to increase with increasing oceanic age as has been previously described for the Pacific. The velocities in the Atlantic Ocean basins were found to be 5 to 8 per cent faster than those for waves of corresponding periods in the Pacific Ocean basins. The distinct differences in velocities between the Atlantic and Pacific oceans provide additional evidence that the upper mantles of these two oceans are not identical.

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