- Shipping Noise
- Pipeline Leak Detection
- Earthquakes & Tsunamis
- Sea Ice Monitoring
In the market of Environmental Monitoring hydrophones are used to learn more about the local marine environment and improve understanding of how underwater sound effects cetacean activity. Hydrophones serve as an education tool for researchers, scientists, and students to help build awareness of the sensitivity of the marine environment and the impacts of commercial shipping. Monitoring of marine acoustic disturbances, changes in ambient ocean noise, and the potential effects of acoustic masking with regards to cetaceans, will help accurately assess the effects of shipping noise on the marine environment.
Pipeline Leak Detection
Environmental monitoring information is used by many people to make informed decisions about the environment. Timely and effective responses to environmental emergencies, such as a oil pipeline leak, are impossible without adequate information. Hydrophones can be used as acoustic leak detectors because they identify the sound or vibration induced by water escaping from pipelines under pressure. When pressurized water leaks from a pipe it creates a sound or an acoustic signal that can travel through both the pipe wall and the water column in the pipeline.
The procurement and timely evaluation of instrumentation data are primary prerequisites for determining the conditions of dams. Portable instruments, such as hydrophones, have been useful in the investigation of deficiencies in dams and have been used effectively to locate leaks. Hydrophones have been particularly useful in measuring leakage through the concrete facings of rockfall embankments where the disruption of the slab joints, or cracks in panels, were primary sources of leakage. The test involves the comparison between background sound intensity with intensity measured in the vicinity of leaks. The hydrophone can be lowered off the side of a boat located over the points of the suspected leakage.
Earthquakes & Tsunamis
Using low frequency hydrophones scientists and researchers record undersea volcanoes and earthquakes just like any other sound. The mass of energy released is what’s known as thrust faulting. Thrust faulting happens when one tectonic plate dives under another. As the seismic energy from the earthquake spreads through the water it can set off a tsunami. Hydrophones that monitor for volcano, earthquake and tsunami sounds can be deployed in various ways. They can be attached to an underwater observatory, they can be dropped into the water from ocean vessels, attached to a float, or anchored to the seafloor. Using these various deployment methods scientists are able to detect earthquakes that strike in the middle of the ocean.
Sea Ice Monitoring
Ice breakup is a major component of the natural ocean sound field. With the recent widespread decreases in sea ice concentrations, researchers want to establishacoustic measurements for the ocean’s natural sound levels prior to increases in anthropogenic activities. Using hydrophones for long-term acoustic monitoring is an effective tool for observing changing levels of ambient sound related to sea ice dynamics, environmental noise-generating mechanisms, and anthropogenic noise, while simultaneously detecting marine mammals.