The Afar Volcanic Province Within the East African Rift System

The Afar Volcanic Province Within the East African Rift System PDF

Author: G. Yirgu

Publisher: Geological Society of London

Published: 2006

Total Pages: 344

ISBN-13: 9781862391963

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The seismically and volcanically active East African Rift System is an ideal laboratory for continental break-up processes: it encompasses all stages of rift development. Its northernmost sectors within the Afar volcanic province include failed rifts, nascent sea-floor spreading, and youthful passive continental margins associated with one or more mantle plumes. A number of models have been proposed to explain the success and failure of continental rift zones, but there remains no consensus on how strain localizes to achieve rupture of initially 125-250 km-thick plates, or on the interaction between the plates and asthenospheric processes. This collection of papers provides new structural, stratigraphic, geochemical and geophysical data and numerical models needed to resolve fundamental questions concerning continental break-up and mantle plume processes. The focus is on how mantle melt intrudes and is distributed through the plate, and how this magma intrusion process controls along-axis segmentation and facilitates break-up.

East African Rifts

East African Rifts PDF

Author: R. W. Girdler

Publisher: Elsevier

Published: 2013-10-22

Total Pages: 187

ISBN-13: 1483257150

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Developments in Geotectonics, 7: East African Rifts focuses on the movements, structure, and behavior of the East African rift system. The selection first offers information on the surface structure and plate tectonics of Afar; tectonic and magmatic significance of volcanism in the Afar depression; and preliminary interpretation of the gravity field of Afar, northeast Ethiopia. Discussions focus on crustal models of Afar based on gravity and seismic data, tectonics, volcanism, geological setting, and crustal extension. The text also elaborates on the gravity survey of the central part of the Ethiopian Rift Valley and an aeromagnetic survey of the Afar triangle of Ethiopia. The book examines the arrangement and development of continental rift zones, East African rift development, and the seismicity of the East African rift system. Topics include earthquake mechanisms, seismicity, and the main categories of rift zones. The manuscript is a dependable reference for readers interested in the East African rifts.

Extreme Natural Hazards, Disaster Risks and Societal Implications

Extreme Natural Hazards, Disaster Risks and Societal Implications PDF

Author: Alik Ismail-Zadeh

Publisher: Cambridge University Press

Published: 2014-04-17

Total Pages: 431

ISBN-13: 1139916394

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This book presents a unique, interdisciplinary approach to disaster risk research, combining cutting-edge natural science and social science methodologies. Bringing together leading scientists, policy makers and practitioners from around the world, it presents the risks of global hazards such as volcanoes, seismic events, landslides, hurricanes, precipitation floods and space weather, and provides real-world hazard case studies from Latin America, the Caribbean, Africa, the Middle East, Asia and the Pacific region. Avoiding complex mathematics, the authors provide insight into topics such as the vulnerability of society, disaster risk reduction policy, relations between disaster policy and climate change, adaptation to hazards, and (re)insurance approaches to extreme events. This is a key resource for academic researchers and graduate students in a wide range of disciplines linked to hazard and risk studies, including geophysics, volcanology, hydrology, atmospheric science, geomorphology, oceanography and remote sensing, and for professionals and policy makers working in disaster prevention and mitigation.

Geology of Afar (East Africa)

Geology of Afar (East Africa) PDF

Author: Jacques Varet

Publisher: Springer

Published: 2018-08-30

Total Pages: 336

ISBN-13: 9783319869469

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This book summarizes the geological knowledge accumulated on Afar in the last 60 years, demonstrating that it is, and will remain, a real “hot spot” for geological and geophysical research. It provides insights into the Earth processes along diverging plate boundaries, the study of both the continental and oceanic lithosphere and underlying asthenosphere, and margins and transitions including magmatic, volcanic, tectonic, sedimentary, hydrothermal and geodynamic processes. The Afar triangle is a geological depression that developed where the Gulf of Aden, Red Sea and East African Rift Valley meet. It is considered to be one of the Earth system’s most important mantle plumes. In 1967, when the first expedition was organized, there was little information on the geology of the area, and even geographic base maps were lacking. However, the first satellite photographs from the Apollo and Gemini space missions offered a complete picture of the Red Sea-Gulf of Aden region, providing a new vision of the Afar triangle. The book describes the unique geological features that make Afar the only place in the world where an oceanic plate boundary with all its successive steps of development can be observed in the open air. It also presents the Afar triangle as one of the cradles of first, now extinct hominids. The Middle Awash area contains sites of several fossil discoveries, such as the well-known Lucy. The hydrothermal processes in Afar provide conditions suitable for the study of the most primitive forms of life (archaebacterial) and it is also one of the few places where significant quantities of telluric energy are available at the surface for geothermal development. Further, the area has economically interesting mineral deposits and illustrates a number of current climate change issues. In addition to providing geological information, the book shows that Afar is an area where an individual human population developed with its own language and culture, and which adapted to the rugged landscape and extremely dry and hot climate. It is a valuable resource for scientists and students, and also serves the needs of the Afar nation, currently split in three different countries as a result of recent historical events.

Magmatic Rifting and Active Volcanism

Magmatic Rifting and Active Volcanism PDF

Author: T.J. Wright

Publisher: Geological Society of London

Published: 2016-09-06

Total Pages: 373

ISBN-13: 1862397295

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A major rifting episode began in the Afar region of northern Ethiopia in September 2005. Over a ten-day period, c. 2.5 km3 of magma were intruded along a 60 km-long dyke separating the Arabian and Nubian plates. Over the next five years, a further 13 dyke intrusions caused continued extension, eruptions and seismicity. This activity led to a renewed international focus on the role of magmatism in rifting, with major international collaborative projects working in Afar and Ethiopia to study the ongoing activity and to place it in a broader context. This book brings together articles that explore the role of magmatism in rifting, from the initiation of continental break-up through to full seafloor spreading. We also explore the hazards related to rifting and the associated volcanism. This work has implications for our understanding of how continents break-up and the associated distribution of resources in rift basins and continental margins.

Geology of Afar (East Africa)

Geology of Afar (East Africa) PDF

Author: Jacques Varet

Publisher: Springer

Published: 2017-11-14

Total Pages: 336

ISBN-13: 3319608657

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This book summarizes the geological knowledge accumulated on Afar in the last 60 years, demonstrating that it is, and will remain, a real “hot spot” for geological and geophysical research. It provides insights into the Earth processes along diverging plate boundaries, the study of both the continental and oceanic lithosphere and underlying asthenosphere, and margins and transitions including magmatic, volcanic, tectonic, sedimentary, hydrothermal and geodynamic processes. The Afar triangle is a geological depression that developed where the Gulf of Aden, Red Sea and East African Rift Valley meet. It is considered to be one of the Earth system’s most important mantle plumes. In 1967, when the first expedition was organized, there was little information on the geology of the area, and even geographic base maps were lacking. However, the first satellite photographs from the Apollo and Gemini space missions offered a complete picture of the Red Sea-Gulf of Aden region, providing a new vision of the Afar triangle. The book describes the unique geological features that make Afar the only place in the world where an oceanic plate boundary with all its successive steps of development can be observed in the open air. It also presents the Afar triangle as one of the cradles of first, now extinct hominids. The Middle Awash area contains sites of several fossil discoveries, such as the well-known Lucy. The hydrothermal processes in Afar provide conditions suitable for the study of the most primitive forms of life (archaebacterial) and it is also one of the few places where significant quantities of telluric energy are available at the surface for geothermal development. Further, the area has economically interesting mineral deposits and illustrates a number of current climate change issues. In addition to providing geological information, the book shows that Afar is an area where an individual human population developed with its own language and culture, and which adapted to the rugged landscape and extremely dry and hot climate. It is a valuable resource for scientists and students, and also serves the needs of the Afar nation, currently split in three different countries as a result of recent historical events.

The Gregory Rift Valley and Neogene-recent Volcanoes of Northern Tanzania

The Gregory Rift Valley and Neogene-recent Volcanoes of Northern Tanzania PDF

Author: John Barry Dawson

Publisher: Geological Society of London

Published: 2008

Total Pages: 116

ISBN-13: 9781862392670

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The structure and volcanic activity of the northern Tanzania sector of the Gregory Rift Valley have hitherto been less well described than those in Ethiopia and Kenya. This book focuses on northern Tanzania where, although the volcanic area is smaller than those to the north, there are major features such as Kilimanjaro, the highest mountain on the African continent; Ngorongoro, one of the largest calderas on Earth; and Oldoinyo Lengai, the world's only active carbonatite volcano. Following an account of the discovery and early exploration of the rift valley, there are descriptions of the individual volcanoes. These are set within the context of the regional geology and geophysics of the rift valley, and in relation to the structural evolution of the rift and its associated sedimentary basins which include Olduvai, an important site in the history of human evolution The volume concludes with a discussion of the volcanism as related to the plume-related African Superswell.