Experimental Determination of the Effect of Dislocations on Shear Anelasticity in Olivine at Seismic Frequencies and High Temperature

这项工作的最终目的是了解 地幔的流变学和那里的条件 负责板块运动。 构造板块的运动 受到地幔流动的调节。 此流程发生在 固体状态，反过来必须通过运动来适应， 晶体内和沿着晶界的缺陷。 为地震 应变波穿过地幔与这些缺陷相互作用 这导致衰减。 这项研究旨在获得一个 了解地震波与缺陷的相互作用， 地幔矿物的单晶。 一种实验装置， 被开发用于测量应变波的衰减， 地震应变和频率以及地幔条件下 温度和化学环境。 橄榄石被选为 由于其丰富的储量， 因为它在地幔之下非常易变形 条件 地幔的应力状态可能是 控制缺陷结构的主要因素。 一个 通过比较， 利用地震数据进行的实验室衰减测量应 最终绘制地幔屈服应力图

The ultimate aim of this work is the understanding of the rheology of the mantle and the conditions there which are responsible for plate motion. The movement of tectonic plates must be accommodated by flow in Earth's mantle. This flow occurs in the solid state and in turn must be accommodated by the motion of defects within crystals and along grain boundaries. As seismic strain waves traverse the mantle they interact with these defects which results in attenuations. This study is aimed at gaining an understanding of the interaction of seismic waves with defects in single crystals of mantle minerals. An experimental apparatus has been developed to measure the attenuation of strain waves at seismic strains and frequencies and under mantle conditions of temperature and chemical environment. Olivine has been chosen as the first minerals to be studied because of its proposed abundance in the mantle and because it is quite deformable under mantle conditions. The state of stress in Earth's mantle is probably the major factor controlling the defect structure there. An understanding of that structure, gained through the comparison of laboratory attenuation measurements with seismic data, should eventually yield stress mapping of Earth's mantle.