Mv. Greening et P. Zakarauskas, SPATIAL AND SOURCE LEVEL DISTRIBUTIONS OF ICE CRACKING IN THE ARCTIC-OCEAN, The Journal of the Acoustical Society of America, 95(2), 1994, pp. 783-790
This paper reports measurements of the spatial and source intensity le
vel distributions of ice cracking events occurring in the rough, centr
al Arctic pack ice. These distributions are computed from a total of 9
16 detected events covering approximately 2 h of data distributed over
several days during April 1988. Measurements of individual events wer
e obtained over the frequency band 16-200 Hz on a 22-e1ement vertical
array and a 7-element horizontal array deployed below the Arctic pack
ice in 420 m of water. The observed spatial distribution of detected e
vents is consistent with a uniform distribution. Source levels from 11
0 to 180 dB//mu Pa-2/Hz at 1 m were measured. The calculated source le
vel distribution for all events approximates a linearly decreasing fun
ction on a log-dB scale of the number of events versus source level. T
he median occurrence of events having source levels within a 1 dB band
centered at 110 dB//mu Pa-2/Hz at 1 m was 4 events per square kilomet
er per minute. This falls to 10(-2) events per square kilometer per mi
nute at 140 dB//mu Pa-2/Hz at 1 m. The mean and maximum numbers of eve
nts are two and ten times greater, respectively.