Publication Date:
2023-08-17
Description:
The strike lines of a multichannel seismic reflection data set recorded off the Pacific margin of Costa Rica were processed as a part of the project PACOMAR. The data were obtained during the cruise SONNE-81 in order to investigate the geodynamic features of the Pacific margin of Costa Rica [Hinz et al., 1996]. Processing of five profiles was performed including a time-migration. Strong multiples occurred consistently on the profiles across oceanic crust. Both amplitude discrimination processes and FK filtering to remove multiples were applied on some lines. Tests were made to optimize deconvolution and filtering. After processing, the amplitude of primary reflectors were increased, and they became more continuous. Multiples in some areas of rugged topography were suppressed but not totally removed. On the lines across the ocean crust reflections from basement were consistently improved by migration. The profiles analysed cross morphological provinces of oceanic crust and the continental margin. On the continental margin strike line, slump and dome structures were observed. They were formed recently consistent with the subduction of seamounts proposed previuosly. On the oceanic crust, a strong Moho reflection was observed on one of the lines at approximately 3 s below the seafloor indicating crust of normal oceanic thickness. On some lines layering of basement was consistently observed, which probably corresponds to layered ocean flood basalts emplaced from the zone of generation of the Galapagos Rift. Two lines crossing the Cocos Ridge show features of the central rift zone. It consists of a graben in which extensional tectonics has persisted since deposition of sediment.
Type:
Thesis
,
NonPeerReviewed
Format:
text
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