Coastal & Marine Geology InfoBank

Home FACS Activities Atlas Geology School Related Sites More

USGS CMG InfoBank: Volcanic Eruptions

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: 00:40 - 02:04 (01:24)
Source: Annenberg/CPB Resources - Earth Revealed - 14. Intrusive Igneous Rocks
Keywords: volcano, eruption, "lava flow", magma, crust, mantle, crystallization, intrusion, "igneous rock", "Mount Saint Helens", Kilauea, "James Sadd"

Our transcription: A volcanic eruption is one of the most awe inspiring sights in all of nature; but whether an eruption is sudden and explosive such as Mt. St. Helens or more subdued like the eruptions of Kilauea in Hawaii, volcanic activity is not an unusual event.
Volcanic eruptions are the pulse of geologic activity in the Earth's interior.
They graphically demonstrate the geologic processes inside the Earth can have a direct impact here on the surface.
The lava that's produced during a volcanic eruption is, of course, rock that melted somewhere beneath the volcano.
Rock melts in a variety of geologic settings in the crust and upper mantle of the Earth depending on the temperature and pressure conditions and on the composition and water content of the rock.
But lava represents only a tiny proportion of the magma that forms within the Earth.
Most of this magma either seeps into voids and fractures within rocks of the Earth's crust, or it rises and intrudes into the cooler rocks above as enormous globs that require thousands or even millions of years to cool.
In fact, most of the rock of this planet was formed from the slow cooling and crystallization of magma deep underground.
This is known as intrusive igneous rock.

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/13.01.01.html
Page Contact Information: InfoBank staff
Page Last Modified: Thu Oct 31 04:26:41 PDT 2013  (chd)