Sidorin I, Gurnis M, Helmberger DV
Seismological Laboratory 252-21, California Institute of Technology, Pasadena, CA 91125, USA.
Science. 1999 Nov 12;286(5443):1326-31. doi: 10.1126/science.286.5443.1326.
A sharp discontinuity at the base of Earth's mantle has been suggested from seismic waveform studies; the observed travel time and amplitude variations have been interpreted as changes in the depth of a spatially intermittent discontinuity. Most of the observed variations in travel times and the spatial intermittance of the seismic triplication can be reproduced by a ubiquitous first-order discontinuity superimposed on global seismic velocity structure derived from tomography. The observations can be modeled by a solid-solid phase transition that has a 200-kilometer elevation above the core-mantle boundary under adiabatic temperatures and a Clapeyron slope of about 6 megapascal per kelvin.
地震波形研究表明，地球地幔底部存在明显的间断面；观测到的走时和振幅变化被解释为空间间歇性间断面深度的变化。走时的大多数观测变化以及地震三分枝的空间间歇性，可以通过叠加在层析成像得出的全球地震速度结构上的普遍存在的一阶间断面来再现。这些观测结果可以用一种固-固相变来模拟，在绝热温度下，该相变在核幔边界上方有200公里的抬升，克拉珀龙斜率约为每开尔文6兆帕斯卡。
