Sanctuary Integrated Monitoring Network
Monitoring Project

Pioneer Seamount Ocean Acoustic Observatory

Principal Investigator(s)

  • Christopher Fox
    National Oceanic and Atmospheric Administration (NOAA)
  • Roger Bland
    San Francisco State University
  • Newell Garfield
    San Francisco State University
  • James Mercer
    University of Washington
Start Date: August 27, 2001
End Date: September 25, 2002

A vertical array of four hydrophones was installed on Pioneer Seamount to passively monitor the Pacific Ocean in the region south of San Francisco, CA. The hydrophones are connected to land via a telephone cable that comes ashore at Pillar Point, CA. Data from the hydrophones were relayed to NOAA PMEL (Pacific Marine Environmental Laboratories) and to SFSU (San Francisco State University) and were made available for public access.

In late August 2001, scientists sailed from San Francisco to Pioneer Seamount, off the coast of central California, and installed underwater hydrophones (known as an array). The hydrophones allow researchers to remotely monitor and record ocean sound to further their understanding of the sources and effects of ocean noise. The ocean sound data were transmitted live over the Internet while the project was in place.

Passive underwater acoustic monitoring allows the detection of a variety of deep-ocean processes at long distances. Some of the sound sources to be studied include earthquakes, volcanic eruptions, landslides, marine mammal and fish vocalizations, weather, and manmade noises.

Acoustic signals ceased on September 25, 2002. Testing by University of Washington engineers indicate a cable fault approximately 25 miles offshore. A remotely operated vehicle (ROV) from MBARI surveyed and photographed the cable in the summer of 2003. Survey results indicated the cable should not be repaired due to costs and environmental impacts.

Summary to Date

The loudest and most obvious signals detected by the array were those created by passing ships. Ship traffic and relative ship size can be inferred from the dataset. We also identified a method for analyzing the ship signals to determine the speed of each ship and its distance of closest approach to the array.

Further work is planned to investigate the possibility of identifying individual whales from their calls.

For more information, see

Monitoring Trends

  • Blue, Fin, Humpback, and Sperm whales were heard on Pioneer Seamount. Humpback and blue whales calls appear to be predominant. Seasonality was evident with most calls appearing in winter and fall months.
  • Sounds from blue whales were quite prominent over 8 months of monitoring. We have found the "B" call of the blue whale to be lower in frequency and less variable than previously reported.

Study Parameters

  • Ocean Acoustics

Study Methods

Passive acoustic listening with a vertical four element hydrophone array

Figures and Images

Figure 1. This image depicts the location of the submarine cable on Pioneer Seamount that was being used for NOAAs Sound in the Sea Project. The ~100 km cable connected Pillar Point Air Force Station to a passive underwater hydrophone array.

Figure 2. The loudest ship signals. Signals like this arrive about once every three days. They are the loudest sounds observed at the Pioneer Seamount.

Figure 3. The call of a northeast Pacific blue whale is perhaps the best known to date. It generally consists of two parts, A and B. The A call is a series of pulses (on the order of 1.5 pulses/sec), while the B call is a long moan.