• Economic and Environmental Geology
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• v.37 no.2
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• pp.235-244
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• 2004

The shear strength of deep-sea core sediments from the nofheast equatorial Pacific was measured in various conditions to ensure precision of results. The comparison items were 1) two different measuring systems (hand-held vane and motorized vane), 2) in different places of on-board immediately after collecting the core samples and on-land laboratories after storing these samples for three months in a cold room, 3) two different core samples from a multiple corer within a sampling station, and 4) four different measuring points (holes) from a core sample. In this experiment, the values of shear strength in deep-sea sediments show significant change with depth which increase toward the bottom of core. Also, the results of two cores recovered at the same station indicate that vertical variation of shear strength is mainly caused by the change of physical properties. They strongly support the fact that the difference of vue syrtem and/or experimental conditions are not major factor in the variation of geotechnical properties.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.4
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• pp.390-399
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• 1999

Siliceous and calcareous deep-sea core sediments were collected by a multiple corer from the KODOS (Korea Deep Ocean Study) area, northeast equatorial Pacific, to compare vane shear strengths measured by two different apparatuses and in different places of on-board and on-land laboratories. The apparatuses were 1) a hand-held vane with four blades of $2.0{\times}2.0$ cm, and 2) a motorized shear vane system with four blades of $1.0{\times}0.88$ attached on a rotational viscometer. Depth profiles of shear strengths of core samples determined by the apparatuses do not show any consistent difference. Also, there is no consistent difference between shear strength values measured on-board and on-land laboratories after storing the core samples for three months in a cold room by a motorized shear vane system. However, there are considerable differences between depth profiles of shear strengths measured at four different points (holes) of a core sample. Moreover, significant differences among the profiles of different tube samples from a multiple corer within a sampling station were observed. Heterogeneity in physical properties of each depth and sediment column, possibly due to bioturbation and bottom current flows, is likely responsible for the differences in the geotechnical properties.