Developing a Method for Experimental Studies of Crustal Structure in Marine Areas in Different Seasons

Аннотация

A method for experimental studies of crustal structure and composition in marine areas during warm and cold seasons is described. The method employs an electromagnetic low-frequency hydroacoustic transmitter, which generates complex phase-shift keyed signals (M-sequences) in water with a center frequency of 33 Hz, and a mobile laser strainmeter with a measuring arm length of 6 m. In an area with a sea depth of 14 m, the transmitter was lowered to a depth of 12 m. Processing of the obtained experimental data revealed five arrivals of transmitted phase-shift keyed signals to the laser strainmeter, which propagated along the layer boundaries of the upper crust of marine areas. The propagation velocities of these signals have been determined. In winter, they are approximately 2600, 2140, 1750, 1550, and 1280 m/s; in spring, 2250, 1950, 1700, 1480, and 1300 m/s. The calculated velocities agree well with the model data. Future results will make it possible to create a technology to remotely study crustal structure and composition in shelf zones, including shelf zones covered by ice, without destroying it.