IN-SITU ACOUSTIC SCINTILLATION FLOW SENSOR WITH APPLICATION TO HYDROTHERMAL VENTS

WE PROPOSE TO STUDY THE FEASIBILITY OF DEVELOPING AN IN-SITU ACOUSTIC SCINTILLATION SENSOR FOR MEASUREMENT OF MEAN FLOW ACROSS AND ALONG THE LINE SEPARATING TWO OPPOSING ACOUSTIC TRANSCEIVER ARRAYS. SUCH A DEVICE SHOULD BE CAPABLE OF MEASURING FLOW COMPONENTS IN A 2-DIMENSIONAL AREA DEFINED BY THE ARRAYS. IT COULD BE ADAPTED FOR RESOLVING FLOW SCALES FROM LESS THAN 1 M TO SEVERAL KM. THE STUDY WILL FOCUS ON THE APPLICATION OF THIS SENSOR TO MEASURING FLOW PROPERTIES OF HYDROTHERMAL VENTS AND VENT FIELDS, INCLUDING MEAN FLUX AND TEMPORAL VARIABILITY IN FLUX, TEMPERATURE, INTENSITY OF REFRACTIVE INDEX TURBULENCE AND ECHO BACKSCATTER. FOR THE PURPOSE OF EVALUATING THE PRACTICAL REALIZABILITY AND PERFORMANCE OF THE GENERAL APPROACH, WE WILL FOCUS ON 1-M SCALE MEASUREMENTS FOR STUDY OF FLOW FEATURES OF INDIVIDUAL VENTS, AND 100-M SCALE MEASUREMENTS FOR STUDY OF VENT FIELDS. WE WILL CARRY OUT EXTENSIVE THEORETICAL STUDIES TO DETERMINE THE INFLUENCE OF THE ENVIRONMENT'S ACOUSTIC PROPAGATION CHARACTERISTICS ON MEASUREMENT ACCURACY. LIMITED-SCALE LABORATORY AND FIELD TESTING WILL THEN BE PERFORMED TO VERIFY THE THEORETICAL RESULTS. THIS WILL PROVIDE A SOUND BASIS FOR THE FURTHER DEVELOPMENT OF A PROTOTYPE INSTRUMENT.