Ocean Acoustics → Interactive

Masking Zone Viewer

Drag the source level slider and watch two zones respond differently. The shutdown zone (160 dB threshold) collapses quickly with attenuation. The communication masking zone barely budges. This is why bubble curtains solve one problem but not the other.

Source Level

Default: 210 dB (typical with basic mitigation). Unmitigated impact: 220 dB.

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0.8
Shutdown (km)
81.8
Masking (km)
102x
Ratio

Zone Comparison (not to scale)

Level B Shutdown Zone (160 dB)
Communication Masking Zone (1 km call-detection criterion)

Why the asymmetry? The shutdown threshold (160 dB SPLrms) is close to the source level, so small reductions in source level produce large reductions in zone radius. The communication criterion is more demanding: pile noise must fall low enough for a modeled whale call to remain detectable over 1 km. That boundary sits much farther from the source, where the same source reduction removes a smaller share of the radius.

This viewer reproduces the foundation-comparison screening calculation: TL = 17.5 · log10(1000rkm) + 0.3rkm dB, evaluated on a 0.1 km grid. The Level B boundary uses 160 dB SPLrms. The communication boundary assumes a 160 dB whale call, spreading loss over 1 km, and an 8 dB detection margin. Values between the named technology fixtures are model interpolations, not new RAM PE runs.

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