Hydroacoustics of a submarine eruption in the Northeast Lau Basin using an acoustic glider

Abstract

A 1000-m Slocum glider® (Teledyne Webb Research Corporation) with CTD, turbidity, and hydrophone sensors was operated for two days in the Northeast Lau Basin. The survey was conducted near West Mata Volcano, where in November of 2008 the NOAA PMEL Vents program observed an active eruption emanating from near its summit at 1207 m-the deepest submarine activity ever to be witnessed. Our goal was to use the glider as a forensic tool to search for other nearby eruption sites with onboard sensors that detect the chemical and hydroacoustic signatures associated with the volcanic and hydrothermal plumes. The glider was launched on May 6, 2010 at 15° 8'3.60"S-174° 6'15.00"W, approximately 40 km to the west of West Mata. It flew toward West Mata and was recovered near the summit of the volcano after repeating 13 yos during a 41-hour mission. Although the recordings were affected by mechanical noise from the glider's rudder, the data demonstrate that the system can detect the wide-band noises (>1 kHz) associated with submarine volcanic and intense hydrothermal activity. The glider recorded variable acoustic amplitudes based on its distance from West Mata and temporal variations in the volcano's rate of activity, and demonstrated that these geologic processes contribute to the region's high ambient noise levels.