| Spatio-temporal characteristics of acoustic emission during the deformation of rock samples with compressional and extensional en-echelon faults |
| |
| 作者姓名： | 蒋海昆 马胜利 张流 侯海峰 曹文海 |
| |
| 作者单位： | JIANG Hai-kun1) MA Sheng-li2，3) ZHANG Liu2，3) HOU Hai-feng1) CAO Wen-hai1) 1) Seismological Bureau of Shandong Province，Jinan 250014，China 2) Institute of Geology，China Seismological Bureau，Beijing 100029，China 3) Laboratory of Tectonophysics，Ch |
| |
| 基金项目： | Project Study on the Short-term Forecasting Technique of Strong Earthquake (01-04-01) during the Tenth Five-Year Plan from Ministry of Science and Technology of China，and Joint Seismological Science Foundation of China (102037). |
| |
| 摘 要： | Introduction By the experimental techniques of acoustic emission (AE) and surface strain observation, a lot of achievements on the study of deformation and fracture process of samples with en-echelon faults has been obtained (Bomblakis, 1973; LIU, et al, 1986; DU, et al, 1989; LI, et al, 1989; ZHANG, FANG, 1989; ZHANG, LI, 1989; MA, et al, 1995a, b; LI, et al, 2000). However, there still exist many problems. For example, most of discussion on the spatio-temporal evolution of microf…
|
| 收稿时间： | 4 June 2001 |
| 修稿时间： | 17 April 2002 |
Spatio-temporal characteristics of acoustic emission during the deformation of rock samples with compressional and extensional en-echelon faults |
| |
| Jiang Hai-kun , Ma Shengli , Zhang Liu , Hou Hai-feng and Cao Wen-hai.Spatio-temporal characteristics of acoustic emission during the deformation of rock samples with compressional and extensional en-echelon faults[J].Acta Seismologica Sinica(English Edition),2002,15(4):402-413. |
| |
| Authors: | Jiang Hai-kun Ma Shengli Zhang Liu Hou Hai-feng and Cao Wen-hai |
| |
| Institution: | 1. Seismological Bureau of Shandong Province, Ji'nan 250014, China
2. Institute of Geology, China Seismological Bureau, Beijing 100029, China;Laboratory of Tectonophysics, China Seismological Bureau, Beijing 100029, China |
| |
| Abstract: | The spatio-temporal characteristics of acoustic emission (AE) during the deformation of rock samples with compressional and extensional en-echelon faults have been studied. The results show that the pre-existing structure can significantly influence the patterns of AE spatial distribution. With increasing of differential stress, AE events firstly cluster around the two ends of pre-existing faults inside the jog and then along the line joining the two ends. The biggish AE events often occur around one end repeatedly. The image of AE clusters indicates the direction and the area of the fracture propagation. The direction of the macroscopic fracture in extensional and compressional jogs is perpendicular and parallel to the direction of axial stress, respectively. The weakening process before the fracturing of jog area is remarkable, and one of the typical precursors for the instability is that the cumulative frequency of AE events increases exponentially. After the fracturing of the jog the frequency and releasing strain energy of AE events decrease gradually. During the friction period, there is no precursory increasing of AE activity before the big stick-slip events. The change of b value in jog shows a typical change of decreasing tendentiously returning quickly before the instability. The decrease of b value occurs in the process of stress increasing and sometime goes down to the weakening stage, and the quick increase b values appears in a short time just before the instability. The comparative analysis shows that the difference in b value due to the different structures is larger than b value variation caused by increase of the differential stress. For the same sample, the temporal sequence of AE is strongly affected by the mechanical state, and the high loading velocity corresponds to the high release rate of strain energy and low b value. Due to its lower failure strength, the broken area is sensitive to small changes in differential stress. Therefore, it offers a potential explanation for the phenomena of precursory window or sensitive point and separation of seismic source and precursors. |
| |
| Keywords: | acoustic emission rock sample compressional en-echelon fault extensional en-echelon fault biaxial experiment differential stress |
| 本文献已被 CNKI 万方数据 SpringerLink 等数据库收录！ |
|
