Measurements of Sound Absorption and Sound Speed in Terrigeneous Sediments

THE ABSORPTION AND SPEED OF SOUND WERE MEASURED BETWEEN TWO BORE HOLES EACH 150 M DEEP AND SPACED 4 M APART. SEDIMENT PROFILE SAMPLES HAVE BEEN OBTAINED FROM THE TWO WELLS AND THE WATER CONTENT, POROSITY, DENSITY AND MINERALOGY DETERMINED. ACOUNSTIC MEADUREMENTS WERE MADE AT SELECTED DEPTHS IN THE WATER SATURATED SEDIMENTS DOWN TO A MAXIMUM OF -83 M. THE ACOUSTIC FREQUENCIES RANGES FROM 7.5 TO 18 KHZ; AT THE LOWER FREQUENCY, THE ABSORPTION VARIED FROM 0.3 DB/M IN CLAY TO 0.4 DB/M IN SAND. AT 18 KHZ THE CORRESPONDING VALUES WERE 2.0 DB/M AND 4.5 DB/M, RESPECTIVELY. MEASUREMENTS OF SOUND SPEEDS FOR CLAY RESULTED IN A VELOCITY OF 1480 PLUS/MINUS 15 M/S, 1540 TO 1820 PLUS/MINUS 15 M/S IN SILT AND 1540 PLUS/MINUS M/S FOR SAND, AT A TEMPERATURE OF 12 DEGREE C. THE ABSORPTION MEASUREMENTS COMPARE WILL AT 12 KHZ TO THOSE MADE LATE 1986 IN DEEPT OCEAN SEDIMENTS USING PENETRATORS WHICH WERE ABLE TO PENETRATE UP TO 55 M INTO THE SEDIMENTS.

WEYDERT Marco;  D'ALESSANDRO Marco; 

1995-03-15

JRC4856

https://publications.jrc.ec.europa.eu/repository/handle/JRC4856,