Frequently Asked Questions:
Where and when do you propose to do this survey?
If we are authorized following the pending environmental compliance process, we plan to survey around Santorini Volcano in Greece. The survey would be conducted during the November-December 2015 time frame
Our goal is to seismically image the magmatic plumbing system beneath the volcano throughout the entire crust. This is important for understanding the geological hazards at Santorini (the potential and possible size of volcanic eruptions, the probability of earthquakes, and the generation of tsunamis) . This geophysical study would also help understand how the composition of magma changes from that formed in the mantle to the composition that forms the bulk of the continental crust.
The project was funded by the National Science Foundation (NSF) through a peer-reviewed award to researchers at the University of Oregon. If we are authorized following the environmental compliance review now in progress, we would use the R/V Langseth, the premier U.S. academic seismic research vessel, which is owned by the NSF and operated by the Lamont-Doherty Earth Observatory of Columbia University.
If, following the environmental compliance process, our survey is approved, our data would be computer-processed and ready for scientific analysis roughly five months after the cruise. It would then be placed in a NSF-supported archive.
How do you propose to collect the data?
Like a medical sonogram that uses sound to make an acoustic image of tissue beneath the skin, our proposed plan is to make acoustic images of layers below the seafloor using seismic airguns as our sound source.
An airgun is a device towed roughly 100 feet behind a ship that at regular intervals releases a bubble of compressed air below the sea surface. Like the pop of a balloon that creates a sound wave, an airgun creates a sound wave that travels down and into the seafloor. Seismometers placed on the seafloor record these waves after they have travelled through the earth.
We propose to use 4 strings of 9 airguns each towed 12 meters below the sea surface. They would release a total of 6,600 cubic inches of compressed air that would rise to the surface as a cloud of small bubbles and spread out as a sheet of white foam about five feet in diameter; no spray of water would rise off the sea surface.
How do you propose to protect endangered marine mammals?
We would adhere to protection protocols determined by the federal environmental compliance process, detailed explanation of which can be found in the National Science Foundation’s Environmental Analysis (EA) prepared pursuant to Executive Order 12114 and in the application for an Incidental Harassment Authorization (IHA) submitted to the National Marine Fisheries Service (NMFS). A condensed overview is provided here. The pending request would require the R/V Langseth to employ a number of mitigation and monitoring measures to reduce potential impacts to marine species during the proposed survey, including vessel speed reduction or minor course alteration, and the use of passive acoustic monitoring of marine mammals. In addition, five Protected Species Observers (unrelated to and not funded by the research grant) would maintain visual watches for marine species around the vessel from a tower 70 feet above the ship’s waterline. They would have absolute authority to enforce any terms and conditions of an IHA, including shutting down the acoustic source if marine species are observed entering a specified radius around the vessel. With the proposed mitigation and monitoring measures, impacts to marine mammals and sea turtles would, at most, be expected to be limited to short-term, localized changes in behavior and distribution close to the vessel. No injury or death of marine species would be anticipated from the proposed activities.
Yes. The National Marine Fisheries Service (NMFS) gathers information and advice from the many agencies described above, yet does not issue a permit for Incidental Harassment Authorization (IHA) until it has also heard from those who respond to its call for public comments. Individuals and groups are invited to submit comments regarding the draft IHA, and are encouraged to include any supporting data or citations to help inform the final decision of the NMFS. A 30-day public comment period began on Sept 4th, 2015.