Effect of a soft sediment layer over elastic basement on normal mode dispersion

2019 ◽  
Vol 145 (3) ◽  
pp. 1672-1672
Author(s):  
Gopu R. Potty ◽  
James H Miller ◽  
Julien Bonnel
Keyword(s):  
Normal Mode ◽  
Sediment Layer ◽  
Soft Sediment ◽  
Mode Dispersion ◽  
Elastic Basement

Acoustic wave reflection from a rough seabed with a continuously varying sediment layer overlying an elastic basement

2004 ◽  
Vol 275 (3-5) ◽  
pp. 739-755 ◽  
Author(s):  
Jin-Yuan Liu ◽  
Sheng-Hsiung Tsai ◽  
Chau-Chang Wang ◽  
Chung-Ray Chu
Keyword(s):  
Acoustic Wave ◽  
Wave Reflection ◽  
Sediment Layer ◽  
Elastic Basement

Leaking and normal modes as a means to determine crust-upper mantle structure for different paths to Sweden

1969 ◽  
Vol 59 (4) ◽  
pp. 1695-1712
Author(s):  
Abou-Bakr K. Ibrahim
Keyword(s):  
Normal Mode ◽  
Upper Mantle ◽  
Structural Model ◽  
Normal Modes ◽  
Mantle Structure ◽  
S Waves ◽  
Kurile Islands ◽  
Mode Dispersion ◽  
Upper Mantle Structure ◽  
Wave Trains

Abstract By using the leaking and normal mode dispersion curves, the average crustal and upper mantle structure is determined for seven different paths. The paths originate from earthquakes in Greece, Turkey, West Pakistan, Tibet, Kamchatka, Kurile Islands and Mexico. Records from Uppsala and Umeå, Sweden, are used. The characteristics of the leaking modes at different distances are examined. Surface waves are used to put more constraint on the models chosen using only the leaking wave data and to verify their mode of propagation. A good fit for observational data of both the leaking mode (PL or PLH2) and the normal mode (Rayleigh) is found to one model for each path. The average crustal structures from Greece and Turkey to Uppsala are identical. The crustal and upper mantle models for paths from Tibet, West Pakistan, Kamchatka and Kurile Islands have approximately the same velocities but different crustal thicknesses. The dispersion characters of Mexican and North American paths are similar, while the average crustal thickness for the Asiatic paths is 5-15 km greater than for the Mexican path. Since the dispersions of the leaking and normal modes are explained by one and the same structural model, it indicates that our hypothesis about the propagation of the leaking waves is true, and that a substantial portion of the long-period wave trains between the P and S waves can be explained in terms of these leaking modes.

scholarly journals Normal mode dispersion and time warping in the coastal ocean

2019 ◽  
Vol 146 (3) ◽  
pp. EL205-EL211 ◽  
Author(s):  
Oleg A. Godin ◽  
Boris G. Katsnelson ◽  
Tsu Wei Tan
Keyword(s):  
Normal Mode ◽  
Coastal Ocean ◽  
Time Warping ◽  
Mode Dispersion

scholarly journals Palaeoseismicity in the Koteshwor area of the Kathmandu Valley, Nepal, inferred from the soft sediment deformational structures

2000 ◽  
Vol 22 ◽  
Author(s):  
A. P. Gajurel ◽  
P. Huyghe ◽  
B. N. Upreti ◽  
J. L. Mugnier
Keyword(s):  
Slope Failure ◽  
Lacustrine Sediments ◽  
Historical Earthquakes ◽  
Seismic Intensity ◽  
Sediment Layer ◽  
Soft Sediment ◽  
Ground Shaking ◽  
Basal Zone ◽  
Marker Layer ◽  
Sediment Deformation

Palaeoseisms have left their imprints within the Plio-Pleistocene tluvio-lacustrine soft sediments of the Kathmandu Basin. Recently, a temple foundation excavation at Koteshwor exposed a soft sediment layer with deformation al structures. The deformed horizon ranges in thickness from 60 to 90 cm. It can be separated into the following three zones, from top to bottom, respectively: (1) homogenised zone. (2) ball-and-pillow zone, and (3) basal zone. The shaking forces strongly agitated the topmost soft-sediment layer, and in this process, the sediments wcre mixed-up, producing subsequently the homogenised zone. At Koteshwor, the homogenised zone ranges in thickness from 15 to 20 cm. It is associated in a few places with micro-debris containing carbonised wood fragments. In the ball-and-pillow zone, the ball-and-pillow structures are 35-79 cm long and 11- 35 cm high. The laminae of the ball-and-pillow structures are strongly folded or disrupted and recumbent folds are locally observed. The central parts of the ball-and-pillow structures are mostly homogenised and 2-3 cm long wood fragments are accumulated in a few places at the bottom of these structures. In the basal zone (up to 55 cm thick), sediments are upraised and plastically deformed. A marker layer in the basal zone attests to the simultaneity of compression and extension deformational structures, a combination of structures that excludes the slope failure origin for the soft sediment deformation and that is clearly related to ground shaking during an earthquake. The fluvio-lacustrine sediments of the Kathmandu Basin consist of a thin alternation of weakly consolidated and cohesionless silty and sandy layers exhibiting rather good sorting. These conditions and physical properties make them suitable for hydroplastic deformation, liquefaction, and/or tluidisation. Previous studies showed that earthquake-induced liquefaction and fluidisation deformational structures are connected with seismics hocks of M>5. The soft sediment deformational structures with a thickness varying between 60 and 90 cm in a lacustrine environment are formed in seismic intensity zones greater than IX. It is therefore interred that the palaeoseism intensity at Koteshwor was larger than the intensities of the 1833 and 1934 historical earthquakes affecting the Kathmandu Basin.

3D soft-sediment deformation structures: evidence for Quaternary seismicity in the Madrid basin, Spain

Terra Nova ◽  
1997 ◽  
Vol 9 (5) ◽  
pp. 208-212 ◽  
Author(s):  
P.G. Silva ◽  
J.C. Canaveras ◽  
S. Sanchez-Moral ◽  
J. Lario ◽  
E. Sanz
Keyword(s):  
Soft Sediment ◽  
Deformation Structures ◽  
Sediment Deformation ◽  
Soft Sediment Deformation

Dead Sea shoreline facies with seismically-induced soft-sediment deformation structures, Israel

2000 ◽  
Vol 49 (4) ◽  
pp. 197-214 ◽  
Author(s):  
Dan Bowman ◽  
Dorit Banet-Davidovich ◽  
Hendrik J. Bruins ◽  
Johannes Van der Plicht
Keyword(s):  
Dead Sea ◽  
Soft Sediment ◽  
Deformation Structures ◽  
Sediment Deformation ◽  
Soft Sediment Deformation
Sign in / Sign up

Export Citation Format

Share Document