Accession Number:

ADA247205

Title:

Geoacoustic Model of the Strait of Korea

Descriptive Note:

Final rept.

Corporate Author:

NAVAL OCEANOGRAPHIC AND ATMOSPHERIC RESEARCH LAB STENNIS SPACE CENTER MS

Personal Author(s):

• Briggs, K. B.
• Fischer, K. M.

Report Date:

1991-10-01

Pagination or Media Count:

51.0

Abstract:

Understanding geology of the Strait of Korea is critical for predictions of acoustic response because the region is a shallow-water, bottom- interacting area. Sediments are predominately terrigenous with a significant marine biogenic component and a wide range of textures. Sediments are distributed along the axis by strong currents that winnow fines and leave coarser material as the lag deposit. However, a conspicuous mud belt of silty clay derived from nearby rivers persists near the Korean shore. This deposit thins toward the center where relict fine and medium sands are exposed. On the Japan side, hydrodynamic stress from currents waft away finer sediment to expose rock and leave coarse material in surface sediments. Over most of the strait, recent sea level changes have produced a middepth reflector beneath unconsolidated surface sediments. This acoustic horizon demarcates the surface of previously subaerially exposured marine sediments. Below the approximately 1 km thick layer of sediments, acoustic basement is rough due, largely, to extensional tectonism associated with the back-arc-basin environment of nearby Sea of Japan. Acoustic basement consists of folded sandstone or faulted basalt with extrusively and intrusively emplaced volcanic rock. In this study, the sea floor is differentiated into 17 provinces based on sediment type, thickness, and presence or absence of layering. A transect from Goto Islands in Japan to Kohung Peninsula in Korea was selected to model in detail. This transect traverses four of the largest geoacoustic provinces and samples the range of environments found in the strait.

Descriptors:

• *GEOLOGY
• *GEOACOUSTICS
• *ACOUSTIC DATA
• *OCEAN BOTTOM
• *KOREAN STRAIT
• *SEDIMENTS
• STRESSES
• VELOCITY
• THICKNESS
• OCEAN CURRENTS
• PREDICTIONS
• MODELS
• SURFACES
• SHALLOW WATER
• ACOUSTIC PROPERTIES
• SEA LEVEL
• HYDRODYNAMICS
• TEXTURE
• RANGE(EXTREMES)
• KOREA
• SANDSTONE
• CLAY
• SEDIMENT TRANSPORT
• BASEMENTS
• MUD
• SHORES
• DEPOSITS
• PARAMETERS
• PHYSICAL PROPERTIES
• GRAIN SIZE
• SAND
• ROCK
• BASALT

Subject Categories:

• Physical and Dynamic Oceanography
• Geology, Geochemistry and Mineralogy
• Acoustics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE