USE OF VIBRATORY CORING SAMPLERS 

 FOR SEDIMENT SURVEYS 



by 

 Edward P. Meisburger and S. Jeffress Williams 



I . INTRODUCTION 



In the early studies of geological oceanography the use of a grab-type 

 sediment sampler was the only method of retrieving physical samples from the 

 surface of the seabed. Although this method is relatively inexpensive and still 

 adequate for obtaining small quantities needed to map surface sediment distri- 

 butions, the sampler yields highly disturbed samples and has limited penetration 

 on cohesionless sediments. 



The need to determine vertical changes in seabed sediments led to the use 

 of coring devices to retrieve continuous and relatively undisturbed samples. . 

 In deep ocean areas where muddy sediments predominate, free-fall gravity corers 

 proved quite effective. However, in nearshore and Continental Shelf environ- 

 ments where dense clay and sandy soils are often abundant, the use of terres- 

 trial borehole equipment mounted on anchored floating platforms was (until the 

 early 1960's) the only means of obtaining core data from these sediments. 

 Because offshore borehole methods are extremely expensive and are usually de- 

 pendent on mild sea conditions, coring equipment that can rest on the seabed 

 and operate remotely from a survey platform was developed. An interesting study 

 on the development of recent coring equipment is presented in Tirey (1972) . 



II. SUBMERSIBLE VIBRATORY CORER 



Soviet scientists and engineers in the early 1950' s were apparently the 

 first to demonstrate that vibratory or oscillatory hammer equipment greatly In- 

 creased rates and depths of core-barrel penetration as well as core recovery. 

 They experimented with vibracorers having core barrels of different dimensions, 

 and with variable frequencies and amplitudes of the vibrating device. Based on 

 this initial work, personnel at the U.S. Naval Ordnance Laboratory subsequently 

 built a prototype vibracore which was successfully tested off the Florida coast. 

 It was designed to collect cores of cohesionless material up to 4 feet (1.2 

 meters) long. 



In 1964, as a result of the extensive beach erosion caused by the Great East 

 Coast Storm of 1962 along the mid-Atlantic region, the Coastal Engineering 

 Research Center's (CERC) predecessor, the Beach Erosion Board (BEB) , initiated 

 the Sand Inventory Program. The objective of the program was to conduct geo- 

 logic surveys of inner shelf areas off eroding coasts to locate, describe, and 

 quantify sand and gravel deposits suitable for extraction and placement on 

 eroded beaches. To satisfy the need to obtain cores up to 13 feet (4 meters) 

 long, personnel at Alpine Geophysical Associates, Inc., Norwood, New Jersey, 

 developed and built the pneumatic Alpine Vibracore in 1963 based on the original 

 Soviet design. The original BEB-CERC contract surveys used the high-resolution 



^TIREY, G.B., "Recent Trends in Underwater Soil Sampling Methods," Underwater 

 Soil Sampling, Testing, and Construction Control, Special Technical Publication 

 501, American Society For Testing Materials, Philadelphia, Pa., 1972, pp. 42-54. 



