我所2016年发表论文欣赏-第二十期

地球所研究生会 · 公众号 · · 2017-05-22 15:44

正文

题目

Complex complete quadratic combination method for damped system with repeated eigenvalues

作者

Yu Ruifang , Zhou Xiyuan and Abduwaris Abduwahit

发表刊物

《EARTHQUAKE ENGINEERING AND ENGINEERING VIBRATION 》

摘要

A new response-spectrum mode superposition method, entirely in real value form, is developed to analyze the maximum structural response under earthquake ground motion for generally damped linear systems with repeated eigenvalues and defective eigenvectors. This algorithm has clear physical concepts and is similar to the complex complete quadratic
combination (CCQC) method previously established. Since it can consider the effect of repeated eigenvalues, it is called the CCQC-R method, in which the correlation coeffi cients of high-order modal responses are enclosed in addition to the correlation coeffi cients in the normal CCQC method. As a result, the formulas for calculating the correlation coeffi cients of high-order modal responses are deduced in this study, including displacement, velocity and velocity-displacement correlation coeffi cients. Furthermore, the relationship between high-order displacement and velocity covariance is derived to make the CCQC-R algorithm only relevant to the high-order displacement response spectrum. Finally, a practical step-by-step integration procedure for calculating high-order displacement response spectrum is obtained by changing the earthquake ground motion input, which is evaluated by comparing it to the theory solution under the sine-wave input. The method derived here is suitable for generally linear systems with classical or non-classical damping.

题目

Seismic images of the mantle transition zone beneath Northeast China
and the Sino-Korean craton from P-wave receiver functions

作者

Ruiqing Zhang a, ⁎ , Zhanyong Gao b , Qingju Wu a , Zhenxing Xie a , Guangcheng Zhang c

发表刊物

《Tectonophysics》

摘要

Seismic data from northeast (NE) China and the Sino-Korean craton were combined to image the upper mantle discontinuitiesat410 and 660km.Fine-scaletopographic variationsonthese two discontinuities provideimpor-tant clues for both delineating geometry of the subducting Pacific slab particularly at arc–arc junction and interpreting regional Cenozoic intraplate volcanism. We used over 90,000 receiver functions from 1916 teleseismic earthquakes recordedby584 broadband seismic stations,primary thoseof temporary seismic arrays. We found the average depths of the two discontinuities to be 410 km and 672 km,respectively, beneaththestudy area. Results show that the 660-km discontinuity is strongly depressed by about 20–30 km in a narrow region beneath and around the Changbaishan volcano, consistent with the results of previous receiver function studies. In contrast, much of the Sino-Korean craton exhibits typical transition zone thickness (~260 km) and thus offers no evidence of a stagnated Pacific slab. Our results also reveal an elevated 660-km discontinuity and a thinner transition zoe both to the west of the observed depression region and beneath the Kuril–Japan arc junction. This feature is most likely due to a tearing of the descending Pacific plate at both its leading and junction edges. An additional elevated 660-km discontinuity together with a thinner transition zone appears in the vicinity of the Dariganga lava field, supporting interpretations of a deep-rooted mantle plume. Our observations of an elevated 410-km discontinuity and a thicker transition zone correlate spatially with the diffuse distribution of volcanism around Hannuoba, Aershan and Wudalianchi. This correlation may suggest lithospheric removal as a mechanism for these magmatic activities.

感谢人才资源部狄传芝老师、第四研究室张盛峰提供论文目录及原文
编辑：贾源源、刘翰林
审阅：杜柠、陈婷、李佳威