Tectonics and Three-Dimensional Structure of Spreading Centers: Microearthquake Studies and Tomographic Inversions

摘要

Two-thirds of the Earth's surface has been formed along a global system of spreading centers that are presently manifested in several different structural forms, including the classic rift valley of the Mid-Atlantic Ridge, the more morphologically subdued East Pacific Rise, and the pronounced en echelon structure of the Reykjanes Peninsula within southwestern Iceland. In the thesis, each of these different spreading centers is investigated with microearthquake studies or tomographic inversion of travel times. Results of these studies are used to constrain the spatial variability of physical properties and processes beneath the axis of spreading and, together with other observations, the temporal characteristics of crustal accretion and rifting.