DISCLAIMER: This article is being kept online for historical purposes. Though accurate at last review, it is no longer being updated. The page may contain broken links or outdated information.
Ocean birth through rifting and rupture
Calais, Eric Department of Earth and Atmospheric Sciences, Purdue University, West Lafayette, Indiana.
Ebinger, Cynthia Department of Geology, Royal Holloway University of London, London, United Kingdom.
Yirgu, Gezahegn Geology and Geophysics Department, Addis Ababa University, Addis Ababa, Ethiopia.
Wright, Tim Department of Earth Sciences, Oxford University, Oxford, United Kingdom.
Lewi, Elias Geophysical Observatory, Addis Ababa University, Addis Ababa, Ethiopia.
- Rifting and rupture processes
- Afar Depression
- 2005 Dabbahu rift episode
- Related Primary Literature
- Additional Reading
The formation of a new ocean basin begins with the rupture of a more than 100-km-thick (60-mi) continental plate, but only after millions of years of heating and stretching. The deep, fault-bounded valleys above the zones of stretching and heating are called continental rift zones. Fortunately for Earth's inhabitants, the rate of geological processes is extremely slow, and the rupture occurs in episodes separated by hundreds of years. Volcanic and earthquake activity in these episodes affects only a sector of the long narrow rift zones, producing a regular along-axis rift segmentation that is maintained in subsequent episodes. In September-October 2005, a 60-km-long (40-mi) segment of the East African rift system in Ethiopia experienced an intense period of localized deformation. Over 162 moderate [body wave magnitude (mb) > 4.5 to 3.9] earthquakes and an explosive volcanic eruption occurred over a 3-week period. Subsequent field, remote sensing, and modeling studies showed that molten rock (magma) was intruded into the plate beneath this 60-km-long rift segment, with cracks and faults forming in the brittle rocks above the narrow zones of magma injection. Thus, we directly observed a rare event—the injection of an approximately 8-m-wide (26-ft) column of magma that will quickly freeze to form a new strip of ocean floor. Continued monitoring of the activity will provide vital information for seismic and volcanic hazard mitigation in East Africa.
The content above is only an excerpt.
for your institution. Subscribe
To learn more about subscribing to AccessScience, or to request a no-risk trial of this award-winning scientific reference for your institution, fill in your information and a member of our Sales Team will contact you as soon as possible.
to your librarian. Recommend
Let your librarian know about the award-winning gateway to the most trustworthy and accurate scientific information.
AccessScience provides the most accurate and trustworthy scientific information available.
Recognized as an award-winning gateway to scientific knowledge, AccessScience is an amazing online resource that contains high-quality reference material written specifically for students. Contributors include more than 10,000 highly qualified scientists and 46 Nobel Prize winners.
MORE THAN 8700 articles covering all major scientific disciplines and encompassing the McGraw-Hill Encyclopedia of Science & Technology and McGraw-Hill Yearbook of Science & Technology
115,000-PLUS definitions from the McGraw-Hill Dictionary of Scientific and Technical Terms
3000 biographies of notable scientific figures
MORE THAN 19,000 downloadable images and animations illustrating key topics
ENGAGING VIDEOS highlighting the life and work of award-winning scientists
SUGGESTIONS FOR FURTHER STUDY and additional readings to guide students to deeper understanding and research
LINKS TO CITABLE LITERATURE help students expand their knowledge using primary sources of information