"Peering beneath an Erupting Volcano on the Bottom of the Ocean"
With Guest ScientistDr. Suzanne Carbotte
Originally presented 10 Mar 2012
Exploration of the Sea Floor Began with “HMS Challenger”
• First organized oceanographic expedition
• Circumnavigated the globe between 1872-76
• Used weighted piano wire to “sound” the sea floor
• Discovered the Mid-Ocean Ridge System
http://life.bio.sunysb.edu/marinebio/ch_01.jpg
In the 1920s, echo-sounding provided technology for real-time images
SO undNA vigationandR anging• First developed in the
1920s• Rapid developments
during “Age of Electronics”
• USS Stewart made soundings across Atlantic
http://oceanexplorer.noaa.gov/history/electronic/media/18_ussstewart.html
In 1923, Francis Shepard went on his Daddy’s yacht, and invented Marine Geology
• Born to a wealthy New England family (Shepard Shipping Co.) in 1897
• Early research focused on the Rockies and other mountains
• Daddy offered his yacht for cruise off NE coast, which opened his eyes to geological problems hidden beneath the waves
• “Father of Submarine Geology”
During World War II, vast amounts of echo-sounding records were collected by
ships crossing the oceans• Originally used for
ASW (anti-submarine warfare)
• US Navy provided many to Lamont after the war for research
http://www.oicinc.com/images/DiagramEchoSounding.jpg
Beginning in the 1950s, Marie Tharp, Bruce Heezen, and their grad students created
physiographic maps of the sea floors
http://www.earthinstitute.columbia.edu/news/images/TharpMapLarge.jpg
Acoustic and seismic research
• has contributed more to understanding Earth’s physical history, natural hazard potential, and climate systems than perhaps all other scientific technology combined
• gives scientists the ability to map the ocean floor, a tool that revolutionized earth sciences 50 years ago with the discovery that continents break apart and tectonic plates shift
Acoustic and seismic research
• revealed the globe-encircling volcanic mid-ocean ridge system, earthquake-producing boundaries of crustal plates, drowned shorelines, and submarine landslide deposits.
Acoustic and seismic research
• opaqueness of seawater to light or radio waves makes it difficult to efficiently study with either optical methods (cameras, etc), or with radar or microwave radiation (such as used in satellites).
• Sound, however, travels freely through the oceans and can be used to measure topography and to map geology, ocean temperatures, and currents
Seismic Imaging
http://www.ldeo.columbia.edu/tamam/approach-imaging-sediments-and-deformation
East Pacific Rise
• Part of Mid-Ocean Ridge System
• Extends northward from Pacific-Antarctic Ridge
• Includes some of the fastest-spreading portions of sea floor
http://www.nature.com/nature/journal/v393/n6686/images/393625aa.eps.2.gif
http://tos.org/oceanography/archive/25-1_fornari2.pdf
“ALVIN”
• Research submersible designed by Allyn Vine for WHOI
• “Mother ship” Atlantis• Can descend deeper than
14,500 ft (4800 m)• Among many accomplishments
was pivotal role in ProjectFAMOUS (1974) http://oceanexplorer.noaa.gov/technology/subs/alvin/alvin.html
http://www.britannica.com/blogs/wp-content/uploads/2009/11/alvin.jpg
Hydrothermal Vents
• Discovered by Alvin in1978 on EPR
• Now known in many other locations
http://www.seasky.org/deep-sea/assets/images/black-smoker-se39.jpg
http://www.photolib.noaa.gov/htmls/nur04512.htm
RIDGE 2000• Multidisciplinary science
research program focused on integrated geological and biological studies of the Earth-encircling oceanic spreading center system
• Integrated Studies focus on geology & biology of spreading center system
• Time Critical Studies enhance detection of volcanoes and other transient events, allow rapid-responsehttp://www.ridge2000.org/
LDEO East Pacific Rise Research
• 3D MultiChannel Seismic Survey of the magmatic-hydrothermal system East Pacific Rise 9°50‘N
• Analysis of 9°50'N East Pacific Rise Seismicity: Insight into Hydrothermal and Magmatic Processes
http://www.ldeo.columbia.edu/3DMCS
http://www.ldeo.columbia.edu/research/office-of-marine-operations
Lamont pioneered many seismic exploration technologies, first with the Vema and continuing now with the Marcus G. Langseth
http://www.ldeo.columbia.edu/research/marine-geology-geophysics
Collecting seismic data as the Marcus G Langseth crosses the ocean