1. The impact of marine seismic air-guns to whale populations
Muhammad Husni Mubarak Lubis
Geophysics Dept.
Colorado School of Mines
Picture was taken from

2. Do you know that…?
383 Cetaceans (whale and dolphins) were stranded in the Northern of Gulf of Mexico from November 3, 2010 – Januari 8, % were found dead. Picture was taken from NOAA

3. Do you know that…?
March 2011, 400 pilot whales were found dead along the shore of Speedweel Island, East Falkland Argentina. Photo was taken from

4. Both area, GOM and Falkland, are really busy with marine seismic exploration activities.
can seismic acquisition programs harm and strand the whale populations?

5. Research shows that air-gun, the wave source in a marine seismic exploration, can affect the existing whale populations near the survey location (Caldwell, 2000).

6. Outline Introduction Sound waves in Seismic Exploration
Sound waves used by Whales
Seismic Exploration  Whales
Conclusion

7. Sound Waves : Seismic Exploration
An air-gun array usually consist of 25 – 100 airguns (
Marine Seismic Survey to find oil and gas (
5 Hz – 80 Hz Frequency with
242 dB re 1μPa – 1m of intensity level (Landrø and Amundsen, 2011)
The seismic energy dissipates with distance

8. Sound waves : Whales
Whale sound producing mechanism from Scheifele (1991), picture was taken from
Whale produces and receives sound waves from
Low Frequency – 10 KHz Frequency (Gausland, 2000) with
236 dB re 1μPa – 1m of intensity level (Møhl et al., 2000)
Whales use sound waves to :
Communicate
Sense
Find food
Navigate

9. Seismic Exploration  Whales
Due to the coincidence of whales’ audiogram with seismic airgun bandwidth, behavioral change can happen. (Gausland, 2000).
Behavioral changes are the swimming direction (from Gary Isaksen’s (ExxonMobil) Presentation).
The change is temporal and localized due to the nature of seismic shot.
The marine mammals’ audiogram coincide with the seismic spectrum. From

10. Seismic Exploration  Whales
Whales and air-gun use similar sound pressure/intensity level. That’s why it will not harm the whales. From usgs.gov

11. Conclusions
The air-gun used in a seismic survey affects the local population of whales by changing their behaviors, swimming direction, temporally. No permanent effect like hearing lost, physical injuries etc.
Although data show that the seismic waves generated by the air-gun do not cause any hearing problems and physical injuries, the stranding of whales still become a mystery.

12. Sources
Lasse Amundsen and Martin Landrø, “Marine Seismic Sources Part IV”, Retrieved January 16, 2012, from
USGS, “Airgun and Source” Retrieved January 16, 2012 from
Discovery of Sounds in the Sea, “Animals and Sound” Retrieved January 16, 2012 from
NOAA, “2010 – 2012 Cetacean Unusual Mortality Event in Northern Gulf of Mexico” Retrieved January 16, 2012 from
MercoPress, “Falklands reports grounding of a pod of 400 pilot whales”, March 19, Retrieved from
Ingebret Gausland, “Impact of seismic surveys on marine life”, August Retrieved from
Jack Caldwell, “Does air-gun noise harm marine mammals?”, August Retrieved from
Bill Dragoset, “Introduction to airguns and air-gun-array”, August Retrieved from
filetype=pdf&id=LEEDFF &idtype=cvips

13. Thank You