East African Rifts

Contents

Foreword

Surface Structure and Plate Tectonics of Afar

Geological Setting. Structure. Afar Floor. Afar Margins. Crustal Extension In Afar. Afar and Plate Tectonics.

Volcanism in the Afar Depression: Its Tectonic and Magmatic Significance

Tectonics. Volcanism. Volcanism of Oceanic Nature. Continental Volcanism. Stratoid Volcanism. Granitic Intrusions. Activity.

A Preliminary Interpretation of the Gravity Field of Afar, Northeast Ethiopia

Compilation of the Bouguer Map. A Quantitative Interpretation of the Bouguer Map. Conclusions.

A Gravity Survey of the Central Part of the Ethiopian Rift Valley

Data. Interpretation. Correlation with Surface Geology. Models. Conclusion.

An Aeromagnetic Survey of the Afar Triangle of Ethiopia (Abstract)

Local Earthquake Phases Observed at Addis Ababa, Ethiopia

Seismic Profiles in the Djibouti Area

Results. Interpretation. Conclusion.

Continental Rift Zones: Their Arrangement and Development

Main Categories of Rift Zones. Main Types of Continental Rift Zones. Rift Zones of Platforms. Rift Zones of Young Folded Regions. Rifts and Rift-Like Belts. Interrelations Between Geosynchnal-Orogenic Belts and Rift Belts. Pre-Cenozoic Rift Zones and Belts.

The Kenya Rift Volcanics: A Note On Volumes and Chemical Composition

Distribution and Volumes. Miocene Volcanics. Pliocene Volcanics. Quaternary Volcanics. Chemical Compositions. Basalts. Trachytic Volcanics. Phonohtic Lavas. Summary and Conclusions.

A Geochemical Study of Silali Volcano, Kenya, with Special Reference to the Origin of the Intermediate-Acid Eruptives of the Central Rift Valley

The Eruptivity of the Central Gregory Rift Valley. Summary of the Geology of Silali. Geochemistry. Discussion. Conclusions.

The Seismicity of the East African Rift System

Seismicity. The Gulf of Aden. The Red Sea. East Africa. Earthquake Mechanisms. Travel Time Delays. Travel Time Delays and Gravity Anomalies.

Study of Microearthquakes in the Rift Zones of East Africa

Locations and Techniques. Results. Conclusion.

Gravity and Magnetic Surveys In Northern Tanzania and Southern Kenya

The Gravity Survey. Interpretation of the Gravity Anomalies. The Regional Bouguer Anomaly. The Axial Positive Anomaly in the Gregory Rift. The Gravity Anomalies Over The Speke Gulf Region. The Gravity Anomalies Associated with the Volcanic Province of Northern Tanzania. Conclusions.

Report On Airmagnetic Surveys of Two Areas in the Kenya Rift Valley

Planning of the Airmagnetic Survey. Airmagnetic Survey of the Lake Magadi Area.

Some Comments On The Results of A Seismic Refraction Experiment in the Kenya Rift

Structure. Seismic Refraction Experiments. Interpretation. Conclusion.

Raleigh Wave Phase Velocities For The Path Addis Ababa-Nairobi

Analysis and Interpretation.

The Structure of East Africa Using Surface Wave Dispersion and Durham Seismic Array Data

The General Seismic Structure of East Africa. Teleseismic P Wave Delay. Surface Wave Dispersion Along The Rift Zone. Seismic Array Data. Apparent Velocities of Regional Earthquake Arrivals. Apparent Velocities of Teleseismic Arrivals. Conclusions.

Heat Flow Measurements In East Africa (Abstract)

List of Authors