NEW! Acoustic Ecology Institute has put together a concise, comprehensive Backgrounder on industrial seismic surveys. This 8-page Word document (designed for the media) gives a quick overview of the issue; detailed summaries of the scope, effects, and possible ways of addressing the issue; 2004 research of note; and links to online resources. [DOWNLOAD BACKGROUNDER(doc)]

Seismic surveys utilize arrays of airguns to produce powerful sound waves; with sophisticated acoustic processing the echoes from these sound waves can provide information about geological structure up to 40km below the sea floor. Seismic surveys are used by academic geologists to study plate tectonics and other topics, and by the oil and gas industry in its search for new hydrocarbon deposits.

There are a handful of seismic survey ships worldwide that are contracted by academic institutions for their studies. At times, these studies move beyond "pure science" and can involve data collection designed at least secondarily for assessing the potential for energy development. Academic surveys use anywhere from 1 to 20 airguns in their arrays; it is quiet common for these surveys to use 6-12 guns. The standard "safety radius" is 1000m, though it can be less on small-array projects.; operations stops when whales are in or approaching this distance from the ship. The ship whose permits have been most often challenged by environmental advocates is the R/V Maurice Ewing, owned by the National Science Foundation and operated by Columbia University's Lamont-Doherty Earth Observatory. The Ewing generally does 4-8 surveys per year, each one lasting between a few days and a couple weeks. It has participated in controlled exposure experiments designed to measure the response of sperm whales to airgun sounds, and runs regular calibration cruises, the most recent of which revealed that sound transmission in shallow water is much stronger than previously believed (since then, the Ewing has expanded its "safety zone" accordingly, to up to a 3000m radius). [SEE RECENT, CURRENT, AND UPCOMING ACADEMIC SURVEY INFO]

Meanwhile, there are about 100 industrial ships equipped with airguns, with 20-30 active at most times, and one or more surveys underway worldwide on most days. Industrial surveys are far more apt to use full-power 20-gun arrays (academic arrays typically make more of an effort to use smaller arrays when possible); however, the standard safety radius is just 500m.

Industrial seismic surveys have been in operation worldwide for decades, with relatively few reports of obvious harm to sea life. While there are some questions about whether injured animals would sink out of sight, it seems fairly clear that in most cases, the loud airguns scare fish and cetaceans away. The biological effects of such displacement are not well studied, and there is some evidence of long-term hearing damage in cetaceans that may be related to chronic airgun or ship noise. During 2004, bioacousticians have begun reporting that airgun noise from distant surveys along the coasts of South America and Africa are the dominant sounds in some mid-Atlantic study sites, making it difficult or impossible to hear the whales or seaquakes they are trying to study. Airgun noise is over 200dB at the source, drops quickly to under 180dB (usually within 50-500m, depending on source level and local conditions), and continues to drop rapidly over the next few kilometers, until leveling off at somewhere around 100dB. At this level, the sound can travel for hundreds or thousands of kilometers; in many or most locations, 100dB is significantly louder than the existing ambient background noise, so the airguns raise the background noise to this level, potentially masking local biological calls and signals.

It is difficult to track industrial survey plans, which are often considered trade secrets, and involve permitting from countries around the world. Some countries have begun to take a harder look at airgun noise; during 2004, Mexico has rejected permits for both academic and industrial surveys, and Brazil is prohibiting surveys near a key marine reserve. Still, worldwide awareness of the long-range acoustic effects of surveys is only beginning to develop. [SEE RECENT, CURRENT, AND UPCOMING INDUSTRIAL SURVEY INFO]

US National Archive of Marine Seismic Surveys (NAMSS) - Online maps/database put together by the USGS [WEBSITE]

Industrial Surveys

As noted above, the global oil and gas industry is very active. At any given time, new exploration plans (which will result in seismic surveys), permitting for new developments (in which surveys are often done periodically to monitor reservoir depletion), and various governmental plans and commercial partnerships are being initiated. We have begun to track some of these developments.

Areas with high levels of seismic survey activity include the Gulf of Mexico, North Sea, Australia, Brazil, West Africa, and Indonesia. Expansion of exploration activity is taking place along the north slope of Alaska and Canada, New Zealand, and the Indian Ocean.

Academic Surveys [BACK TO TOP] [SEE INDUSTRIAL SURVEYS]

Some of the projects listed have public comment periods (generally, an "Incidental Harassment Authorization (IHA)" has a one-month window for public input, followed very closely by the planned activity); others are further along and have been granted their permits. Many industrial operations require no US permits (in general, permits are required if activities are taking place in US waters or are using ships based in the US).

July-November 2006
Chukchi Sea, Beaufort Sea
Three different companies are conducing surveys offshore Alaska and Yukon North Slope during the summer and fall of 2006. NOAA Fisheries included an unusual stipulation aimed at protecting bowhead whale mother-calf pairs from behavioral disruption, calling for power down of airguns if 4 or more pairs encountered received levels of just 120dB; Conoco challenged this provision in court, and in September received a temporary court order allowing it to proceed without monitoring the full 120dB zone. (see AEI News Digest for more info) [READ FEDERAL REGISTER NOTICE] [SEE MMS PAGE WITH LINKS TO INFO ON ALL 4 SURVEYS]

December 2006-January 2007
Southwest Pacific Ocean
Scripps Institute is planning a series of small surveys as part of project examining the seafloor geology off the coast of New Zealand. Two 45 cubic inch airguns will operate for 6-10 hours at each of twelve locations. [READ FEDERAL REGISTER NOTICE]

October, 2007
Batholiths, Queen Charlotte Sound area, British Columbia
BATHOLITHS CANCELLED SEE PRESS COVERAGE
A seismic project that was postponed a couple years ago is gearing up again. The Canadian Environmental Assessment Agency has commenced work on an EA, with public meetings already taking place, public comments expected to be accepted through mid-September, and the EA completed by March 2007. As currently planned, the project will include both onshore and offshore seismic surveys, with about three weeks of offshore survey work, scheduled for late fall, after the local fishing season and before the onset of winter storms. The survey plan is unusual in that it will involve airgun work several miles up narrow fjords, as well as across two straits and down one channel between the mainland and offshore islands. Special care will need to be taken to account for unusual or unpredictable sound propagation in these biologically rich areas. Brochures available from the University of British Columbia research unit show the planned survey routes, while more information on the public comment period is available from CEEA.
[SEE CEEA NOTICE] [BATHOLITHS BROCHURE (2.5MB pdf)] [U of British Columbia Batholiths site] [U of Arizona Batholiths site]

LDEO and NSF retire the R/V Ewing; Replacement Vessel to begin operations in 2007 - The workhorse of the US academic seismic fleet, the R/V Ewing,was retiremed in early 2005. Lamont-Doherty Earth Observatory, which operated the vessel under contract from the National Science Foundation, announced the purchase of a used commercial seismic vessel, the Western Legend, in September 2004. According the a LDEO press release, "the receiving systems used by Western Legend to record the sounds that probe the Earth's interior are substantially more sophisticated than that onboard R/V Maurice Ewing. This will allow greatly improved capabilities of imaging the Earth's deep interior without the need to increase the level of sounds transmitted into the ocean. This is fundamentally important to the research community's ability to make progress in its studies of the Earth's environment while minimizing possible impacts upon marine life." The Ewing was retired in early 2005, while the new ship will be ready for sea trials in the fall of 2006, with science cruises in 2007. [READ PRESS RELEASE]
Updates: The R/V Langseth is currently scheduled to be dedicated in New York in mid-September 2006. LDEO is tracking the progress of the R/V Langseth on the following pages:
[CUBED: 3D SEISMIC REFLECTION BLOG] [LANGSETH STATUS PAGE] [LASGSETH CONVERSION PHOTO LOG] [EWING REPLACEMENT TIMELINE]