[Federal Register Volume 72, Number 169 (Friday, August 31, 2007)]
[Notices]
[Pages 50412-50413]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 07-4267]


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NATIONAL SCIENCE FOUNDATION


Notice of the Availability of a Draft Environmental Assessment

AGENCY: National Science Foundation.

ACTION: Notice of availability of a draft Environmental Assessment for 
proposed activities in the Eastern Pacific Ocean and Caribbean Sea near 
Central America.

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SUMMARY: The National Science Foundation (NSF) gives notice of the 
availability of a draft Environmental Assessment (EA) for proposed 
activities in the Eastern Pacific Ocean and Caribbean Sea near Central 
America.
    The Division of Ocean Sciences in the Directorate for Geosciences 
(GEO/OCE) has prepared a draft Environmental Assessment for a marine 
geophysical survey by the Research Vessel Marcus G Langseth in the 
Eastern Pacific Ocean and Caribbean Sea near Central America, in the 
Exclusive Economic Zones of Costa Rica and Nicaragua (water depths from 
<100 meters to >2500 meters) during January-March 2008, The draft 
Environmental Assessment is available for public review for a 30-day 
period.

DATES: Comments must be submitted on or before October 1, 2007.

ADDRESSES: Copies of the draft Environmental Assessment are available 
upon request from: Dr. William Lang, National Science Foundation, 
Division of Ocean Sciences, 4201 Wilson Blvd., Suite 725, Arlington, VA 
22230. Telephone: (703) 292-7857. The draft is also available on the 
agency's Web site at: http://www.nsf.gov/geo/oce/pubs/MGL_Central_America_2008_EA.pdf.

SUPPLEMENTARY INFORMATION: Lamont-Doherty Earth Observatory (LDEO), 
with research funding from the NSF, plans to conduct a marine seismic 
survey in the Eastern Pacific Ocean and Caribbean Sea near Central 
America during 2008. The research program will take place in the 
Exclusive Economic Zones of Costa Rica and Nicaragua. The surveys will 
use a towed airgun array consisting of up to 36 operating airguns with 
a maximum discharge volume of ~6600 in\3\. They will take place in 
waters from <100 meters to >2500 meters deep.
    LDEO plans to conduct this seismic survey as part of the 
``Subduction Factory,'' or ``SubFac'' initiative of NSF's MARGINS 
program. The SubFac initiative will determine the inputs, outputs, and 
controlling processes of subduction zone systems by obtaining seismic 
measurements of magma flux, are composition, and lower-plate 
serpentinization at the Central American Focus Site. Subduction zones, 
which mark sites of convective downwelling of the Earth's lithosphere, 
exist at convergent plate boundaries where one plate of oceanic 
lithosphere converges with another plate and sinks below into the 
mantle. It is at these subduction zones that the oceanic crust and 
associated sediments are recycled into the deep mantle. Although this 
mixing of the Earth's crustal and oceanic materials produces ore 
deposits and new continental crust in the long term, the immediate 
result is geological activity often expressed as deep, very intense 
earthquakes and extensive volcanism.
    The seismic survey will investigate the volcanic are, back are, and 
downgoing plate in the Costa Rican portion of the Central American 
Focus Site. The study focuses on the central Costa Rican segment of the 
are, the site of important transitions in lava chemistry, because the 
narrow isthmus ~150 km or 93 mi wide) is well-suited for detailed 
seismic imaging using onshore-offshore techniques. A systemic 
understanding of subduction must include a thorough knowledge of the 
volcanic are, which in turn is essential in understanding the 
geochemical recycling processes of the Central American SubFac.
    To investigate the Central American SubFac, seismic survey 
transects are proposed across the isthmus in Costa Rica, along the 
Costa Rican arc and back-arc, the outer rise of the Cocos Plate, and 
the Nicaragua Rise. The cross-arc transect will involve use of seismic 
sources in both the Pacific and Caribbean. To understand arc-building 
processes, the delineation of lateral heterogeneity in crustal 
thickness and velocity at scales of tens of kilometers is required, 
both across and along-arc. In order to achieve this, the study will 
acquire (1) A double-side, onshore-offshore cross-arc profile, (2) an 
along-arc refraction line, (3) an array of seismometers in the arc to 
record all onshore and offshore shots and to allow 3-dimensional (3D) 
tomography, and (4) a refraction survey across the outer rise of the 
downgoing Cocos Plate.
    The marine program will consist of ~2149 km of unique survey 
lines--753 km in the Caribbean and 1396 km in the Pacific. With the 
exception of two lines located in shallow to intermediate-depth water, 
all lines will be shot twice, once at a ~50-m (20-s) shot spacing for 
multichannel seismic (MCS) data and once at a ~200-m (80-s) shot 
spacing for ocean bottom seismometer (OBS) refraction data, for a total 
of ~3980 km of survey lines. There will be additional operations 
associated with equipment testing, startup, line changes, and repeat 
coverage of any areas where initial data quality is sub-standard.
    LDEO has applied for the issuance of an Incidental Harassment 
Authorization (IHA) from the National Marine Fisheries Service (NMFS) 
to authorize the incidental harassment of small numbers of marine 
mammals during the seismic survey. The information in this 
Environmental Assessment supports the IHA permit application process, 
provides information on marine species not covered by the IHA, and 
addresses

[[Page 50413]]

the requirements of Executive Order 12114, ``Environmental Effects 
Abroad of Major Federal Actions''. Alternatives addressed in this EA 
consist of a corresponding seismic survey at a different time, along 
with issuance of an associated IHA; and the no action alternative, with 
no IHA and no seismic survey.
    Numerous species of marine mammals occur off Central America. 
Several of the cetacean species are listed as endangered under the U.S. 
Endangered Species Act (ESA), including humpback, sei, fin, blue, and 
sperm whales. In addition, the endangered West Indian manatee is known 
to occur in shallow waters along the Caribbean coast of Central 
America. Sea turtle species known to occur in Central America include 
the endangered leatherback and hawksbill turtles, the threatened 
loggerhead turtle, the green turtle (considered endangered in the 
breeding colony of Florida and the Pacific coast of Mexico and 
threatened elsewhere), and the olive ridley turtle (designated as 
endangered in the breeding colony of the Pacific coast of Mexico and 
threatened elsewhere). The Kemp's ridley turtle may also occur in the 
Caribbean.
    The potential impacts of the seismic surveys would be primarily a 
result of the operation of airguns, although a multi-beam sonar and a 
sub-bottom profiler will also be operated. Impacts may include 
increased marine noise and resultant avoidance behavior by marine 
mammals, sea turtles, and fish; and other forms of disturbance. The 
operations of the project vessel during the study would also a minor 
increase in the amount of vessel traffic. An integral part of the 
planned survey is a monitoring and mitigation program designed to 
minimize the impacts of the proposed activities on marine mammals and 
sea turtles that may be present during the proposed research, and to 
document the nature and extent of any effects. Injurious impacts to 
marine mammals and sea turtles have not been proven to occur near 
airgun arrays; however the planned monitoring and mitigation measures 
would minimize the possibility of such effects should they otherwise 
occur.
    Protection measures designed to mitigate the potential 
environmental impacts will include the following: A minimum of one 
dedicated marine mammal observer maintaining a visual watch during all 
daytime airgun operations, and two observers for 30 min before start 
up. A passive acoustic monitoring (PAM) array will be monitored 24 h 
per day while at the survey area during airgun operations and during 
most times when the Langseth is underway while the airguns are not 
operating. The use of ramp-up, as well as implementation of power-down 
or shut-down procedures when animals approach a designated exclusion 
zone (EZ) are also important mitigation measures. LDEO and its 
contractors are committed to apply those measures in order to minimize 
disturbance of marine mammals and sea turtles, and also to minimize the 
risk of injuries or of other environmental impacts.
    With the planned monitoring and mitigation measures, unavoidable 
impacts to each of the species of marine mammal that might be 
encountered are expected to be limited to short-term localized changes 
in behavior and distribution near the seismic vessel. At most, such 
effects may be interpreted as falling within the Marine Mammal 
Protection Act (MMPA) definition of ``Level B Harassment'' for those 
species managed by NMFS. No long-term or significant effects are 
expected on individual marine mammals, or the populations to which they 
belong, or their habitats. The agency is currently consulting with the 
NMFS regarding species within their jurisdiction potentially affected 
by this proposed activity.
    Copies of the draft EA, titled ``Environmental Assessment of a 
Marine Geophysical Survey by the R/V Marcus G. Langseth off Central 
America, January-March 2008,'' are available upon request from: Dr. 
William Lang, National Science Foundation, Division of Ocean Sciences, 
4201 Wilson Blvd., Suite 725, Arlington, VA 22230. Telephone: (703) 
292-7857 or at the agency's Web site at: http://www.nsf.gov/geo/oce/pubs/MGI_Central_America_2008_EA.pdf. The NSF invites interested 
members of the public to provide written comments on this draft EA.

    Dated: August 27, 2007.
Dr. Alexander Shor,
Program Director, Oceanographic Instrumentation and Technical Services, 
Division of Ocean Sciences, National Science Foundation.
[FR Doc. 07-4267 Filed 8-30-07; 8:45 am]
BILLING CODE 7555-01-M