HR: 0830h
AN: C11D-0855    [PDF]
TI: Hydroacoustic signals from large icebergs drifting in the Southern Pacific, 2001-2003
AU: Talandier, J
AF: DASE-CEA, B.P. 12, Bruyeres le Chatel, 91680 France
AU: Hyvernaud, O
AF: LDG-CEA, B.P. 640, Papeete, F-98713 French Polynesia
AU: Reymond, D
AF: LDG-CEA, B.P. 640, Papeete, F-98713 French Polynesia
AU: Piserchia, P
AF: DASE-CEA, B.P. 12, Bruyeres le Chatel, 91680 France
AU: * Okal, E A
EM: emile@earth.nwu.edu
AF: Northwestern University, Locy Hall, Evanston, IL 60208 United States
AB: Following our detection of hydroacoustic activity in the Ross Sea in Late 2000, we report on a series of new signals generated at more Northern latitudes (55 to 63 deg. S), and detected both in Polynesia and by IMS stations in the Indian Ocean, during the period 07 Mar 2002 to 15 Jan 2003. Apart from a strong swarm in Nov.-Dec. 2002, they occur as isolated events, lasting between 200 and 1800 s. They consist of numerous repetitive signals (with broad spectrum) superimposed on a background featuring preferential eigenfrequencies. With a few exceptions, the epicenters correlate spectacularly well with the position of Mega-Iceberg B-19 (and its fragments), as it drifted from West of Balleny Islands in Feb. 2002 to (53deg.S; 167deg.W) in Feb. 2003. In particular, the acoustic swarm of Nov.-Dec. 2002 correlates in space and time with a series of erratic motions of B-19 over an area 300 km by 100 km centered at (57 deg.S; 170 deg.W). Since the spectrograms of these more Northerly sources are significantly different from those recorded from the Ross Sea, their sources must involve different physical processes. The latter, which may include the discharge of large boulders, remain mysterious.
DE: 4259 Ocean acoustics
DE: 4540 Ice mechanics and air/sea/ice exchange processes
DE: 9355 Pacific Ocean
SC: Cryosphere [C]
MN: 2003 Fall Meeting