Coastal & Marine Geology InfoBank

Home FACS Activities Atlas Geology School Related Sites More

USGS CMG InfoBank: Magnetic Properties of Volcanic Rocks

Skip navigational links
Loading
Dictionaries: Our Mapping Systems   The USGS and Science Education   USGS Fact Sheets   Topics   Keywords   Data Dictionary   Metadata Dictionary   Computer Terminology   Digital Formats  
InfoBank Terms: Activity ID   activity overview   crew   digital data   formal metadata   lines   metadata   NGDC   port stops   project/theme   region   ship   stations   time   virtual globe   year  
Data Types: bathymetry   biological   geochemical   gravity   ground penetrating radar   imaging   LIDAR   logs   magnetics   metering equipment   navigation   samples   seismic   total station   definitions disclaimer  
Data Formats: ARC coverage   E00   FGDC metadata   gridded/image   imaging   material   scattered/swath   Shapefile   vector/polygon  
Comment: 21:48 - 22:48 (01:00)
Source: Annenberg/CPB Resources - Earth Revealed - 13. Volcanism
Keywords: "Thomas Redfield", magnetism, geophysicist, vent, "magnetic field", temperature, "proton precession magnetometer", "diurnal variation", Noverupta, iron, dome, volcano

Our transcription: Since some rocks are more magnetic than others, geophysicists also map variations in magnetism to help study the subterranean structure of the vent area.
Every rock has some magnetic signature or some magnetic field associated with it that was locked into it at the time of its cooling when it cooled below a certain temperature.
What we do with a proton precession magnetometer is we measure the intensity of everything about you, the magnetic field at that particular point.
And then, with another instrument which is sitting in one place and recording the variations of the Earth's magnetic field, the diurnal variations, the daily variations, we subtract the two, and we are left with a component which we hope is just the rocks themselves.
Magnetic surveying reveals that the area near Noverupta is more magnetic than the surrounding terrain.
The research team believes this results from a concentration of iron rich minerals within and beneath the dome.

Geology School Keywords
Skip footer navigational links

Coastal and Marine Science Centers:  Pacific   St. Petersburg   Woods Hole  
InfoBank   Coastal and Marine Geology Program   Geologic Information   Ask-A-Geologist   USGS Disclaimer  


Accessibility FOIA Privacy Policies and Notices

Take Pride in America logo USA.gov logo U.S. Department of the Interior | U.S. Geological Survey
URL: http://walrus.wr.usgs.gov/infobank/programs/html/school/moviepage/12.01.25.html
Page Contact Information: InfoBank staff
Page Last Modified: Thu Oct 31 04:26:39 PDT 2013  (chd)