Area ratios were determined from 



' 1 ° D " 2 ID ) (1) 



The area ratios are also tabulated in Table 1; however, these 

 values do not include the effect of the sample retainer. The dimensions 

 of the retainer suggest that values in Table 1 should be increased by 

 approximately 10% to include this effect. The implications associated 

 with such high area ratios are reviewed under DISCUSSION OF RESULTS - 

 General. 



The gravity corer was suspended from a tripping mechanism as 

 it was lowered by a ship's cable. When the trip weight contacted 

 the sediment surface, the gravity corer released, fell approximately 

 30 feet, and penetrated the bottom material. The corer utilized 

 500 pounds of lead weight to increase the depth of penetration. A 

 pinger was attached above the tripping mechanism to monitor the 

 position of the corer during the lowering process. 



A short gravity corer functioned as the weight for the tripping 

 mechanism. This trip corer (Table 1) , similar in design to the 

 larger gravity corer ( plastic liner, core retainer, and cutting head), 

 sampled the sediment about 3 feet from the point at which the gravity 

 corer penetrated. The trip corer was 4 feet long and weighed 

 approximately 70 pounds. 



After the gravity corer penetrated the sediment, the winch line 

 was used to pull the device slowly out of the bottom and to the 

 water surface. When the apparatus reached the surface, the winch 

 line was removed, the corer was disassembled, and the sediment 

 sample was stacked in a vertical position. The length of samples 

 from the deep-water site varied from to 3 meters. 



A similar procedure was used to obtain shallow-water sediment 

 samples; however, the trip mechanism and pinger were not included 

 in the operation. The lowering winch was allowed to freewheel during 

 descent, thus achieving a near free fall condition. The length of 

 cores obtained at the shallow-water sites also varied from to 3 

 meters. The typical coring operation lasted from several minutes to 

 an hour, depending upon the depth of the water at the site. 



Vane Shear Testing 



Within several hours of the coring operation, the author evaluated 

 the original and remolded vane shear strengths of the sediment cores 

 by using a Wykeham Farrance laboratory vane apparatus (Figure 1). 



See foldout list of symbols after References. 



