Planetary Geodynamics Laboratoy Science Highlight
NASA GSFC Planetary Geodynamics 698

SCIENCE HIGHLIGHT

Planetary Geodynamics Laboratory, Code 698

January 2005

Purucker Article Accepted by EOS

Magnetic Snapshot Reveals Deep Structure of Sumatra Earthquake Zone

Mike Purucker of Raytheon Technical Services at the Planetary Geodynamics Laboratory, along with co-author Takemi Ishihara of the Geological Survey of Japan, wrote an article on "Magnetic images of the Sumatra region crust", the site of a recent devastating Tsunami. The article will be published in EOS Transactions of the American Geophysical Union.

The great earthquake of 26 December 2004, which gave rise to the devastating tsunami that swept over a large part of the SE Indian Ocean, occurred along a subduction zone in Sumatra where one oceanic plate slides beneath another. Many subduction zones around the world have pronounced signatures not only in marine altimetry and magnetic data, but also in satellite-elevation crustal magnetic data. Satellite magnetic data provide important information on the deep structure of the Earth's crust. The figure below shows how magnetic crustal thickness in the region of the subduction zone increases to the east and northeast, in the direction of subduction at the place where the cold crustal slab dives into the Earth's mantle. Other large scale oceanic crustal structures (ridges, basins) are also evident in this map.

Magnetic crustal thickness in the region of the Sumatra earthquake

Magnetic crustal thickness in the region of the Sumatra earthquake. A composition and thermal model was used as a starting point, then iterated until predicted magnetic intensity matched that in satellite magnetic field data (from which main field and external fields had been removed). Thin magnetic crust is shown by blue areas, thicker crust by red areas.

Picture of Michael Purucker Mike Purucker is a staff geophysicist with Raytheon Technical Services and has worked at the Goddard Space Flight Center for 15 years. He is well-known for studies of crustal magnetic anomalies on both Earth and Mars, and is a member of the Mission Advisory Group for the upcoming European Swarm Mission.

Contacts: Mike Purucker, GSFC Code 698, purucker@geomag.gsfc.nasa.gov

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Responsible NASA official: Dr. Herbert Frey

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Last modified on February 18, 2005