Data Report for Oceanographic/Geophysical Surveys in the Northwest Pacific (46-47 N, 159-161 E): USNS Silas Bent, 2-3 August 1980.
Abstract
This note presents the results of a geophysical/oceanographic survey of Area 2 selected from Green and Fleischer (1980). The surveyed area has an average depth of 5300 m and is located on the eastern flank of the Hokkaido Rise. Average unconsolidated sediment thickness is 0.45 seconds of two-way travel time (approximately 400 m). These sediments are probably siliceous clays interspersed with volcanic ash layers and their calculated acoustic interval velocity is 1.770-1.860 km/sec. The smoothest bottom and most homogeneous geology appear in the northeastern section of the survey area. This section, an area about 25 km x 25 km, has smooth acoustic basement which is present at the northern base of a seamount located at 46.6 N, 159.8 E. Residual magnetic lineations are also present in this area and may represent Cretaceous quiet zone seafloor spreading anomalies. In the western part of the survey area, the bottom and acoustic basement are rougher than in the eastern part. The local geology is less homogeneous because seamounts are present. Residual magnetic anomalies are generally associated with seamounts and no correlatable lineations are apparent. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Mar 01, 1981
- Accession Number
- ADA098902
Entities
People
- J. A. Green
- S. D. Trowell