摘要
用类似于天然地震中尾波持续时间确定震级的方法,通过岩石力学实验研究了含坚固体试样破裂孕育过程中声发射的强度特征。结果表明:在加压初期,声发射强度相对平稳,当应力达78 % 的破裂应力时,声发射强度显著增加,当应力达92% 的破裂应力时,声发射活动强度达到极大值,比加压初期大20 % 以上;随着应力的进一步增加,声发射强度减小,达极小值,出现一个相对平静的阶段;应力再增加,声发射活动强度回升,紧接着,主破裂发生。从声发射强度的空间分布上看,从加压初期的平稳到极大值的出现,声发射都发生在坚固体的外围,随着活动强度减弱,并出现低值之后,强度回升,这个过程基本上发生于坚固体及其上方,随后主破裂发生,坚固体也局部破裂。这和澜沧耿马地震前的地震时间进程具有现象上的相似性。
In this work, using the method determining the earthquake magnitude from coda wave continuous time, the intensity characteristics of acoustic emission in rupture preparation process of the sample including hard inclusion is studied. The results show that the intensity of AE is steady at the early pressuring stage. When the pressure reaches to 89% the rupture pressure stress, the intensity obviously increases; when the pressure comes up to 92% the rupture pressure stress and the intensity reaches the maximum value greater 20% than the value at the initial pressuring stage. Then the intensity falls, drops to the minimum value and relative quiet activity of AE appears at this time with the pressure increasing. With the pressure further increasing, the intensity rises again, following closely the main rupture occurs. As viewed from the space distribution of AE, AE occurs in the periphery of hard inclusion in the process from the steady value at early loading stage to the maximum and roughly appears in the hard inclusion and above it from the low value to recovering of the high value. At last the main rupture occurs and the inclusion rupture locally too, which is similar to the time progress in phenomenon before the Lancang-Genma earthquake.
出处
《地震地质》
EI
CSCD
北大核心
1999年第4期411-416,共6页
Seismology and Geology
基金
中国地震局"九五"科研攻关项目
云南省应用基础研究基金!(97D027Q)
