Detecting and analyzing underwater sound is essential for the maritime industry to monitor water pollution, reduce its carbon footprint, and comply with global regulations. While much has been written about why underwater sound detection is important, this page explores the how—specifically, the materials and technologies used to listen beneath the waves.
What Are the Types of Underwater Sounds?
Underwater, an ever-present acoustic backdrop called ambient noise exists. These sounds can come from:
ship traffic, sonar, oil drilling, offshore construction
Measuring Underwater Sound:
Sound levels underwater are measured in decibels relative to 1 microPascal (dB re 1 μPa). The frequency of underwater sounds ranges from 10 Hz to 1 MHz:
20–500 Hz
Mainly from distant ships
500–100,000 Hz
Wind and wave-related noise
Above 100,000 Hz
Thermal noise from water molecule motion
Applications of underwater acoustics include fishing, marine life monitoring, communication, navigation, defense, geological surveys, and more.
What Equipment Is Used to Detect Underwater Sound?
Hydrophones
Hydrophones act like underwater microphones. Placed on the seabed or floating buoys, they:
Use piezoelectric transducers to convert sound waves into electrical signals
Measure sound pressure levels (SPL)
Can detect sounds from up to 3,000 miles away
Operate at depths of up to 1000 m and high pressure (9.8 MPa)
Hydrophones are widely used in naval applications, including submarine tracking.
Sonar (Sound Navigation and Ranging)
Used for navigation, hazard detection, object mapping, and communication:
Active Sonar
Emits sound pulses ("pings"), then listens for echoes to calculate distance and type of object
Passive Sonar
Listens only; ideal for stealth operations or marine life tracking. Often uses arrays of hydrophones for triangulation
Hydrophones are used in passive sonar systems, but not all hydrophones are part of a sonar device.
All equipment must meet IEC TS 62600-40 standards for consistency and reliability in acoustic data.
How Do Digital Technologies Impact Sound Detection?
Technologies like AI, machine learning, and big data are revolutionizing underwater sound detection:
Real-time data transmission to central dashboards
Automated reports using acoustic analytics
Custom alerts when noise thresholds are exceeded
Integration with other monitoring tools: marine mammals, water quality, aerial acoustics
Some platforms also compare new sound samples against known marine mammal audiograms to evaluate potential impacts on behavior, feeding, or reproduction.
Why Underwater Sound Detection Matters
While completely eliminating ship-generated noise is unrealistic, monitoring and minimizing its impact is both achievable and necessary.
Rising global trade and coastal development are increasing underwater noise pollution
Rising global trade and coastal development are increasing underwater noise pollution
Acoustic environments vary by region and species, so regulations continue to evolve
Digital solutions like Sinay's transform monitoring into actionable insights
Countries like Canada have already implemented protective zones to safeguard endangered marine life, showing how ocean-friendly practices can become a reality.
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