亚洲中东部地区塑性流动波(“慢波”)与地震活动  

PLASTIC-FLOW WAVES ("SLOW WAVES") AND SEISMIC ACTIVITY IN CENTRAL-EASTERN ASIA

作　　者：王绳祖[1] 张宗淳[1] 

机构地区：[1]中国地震局地质研究所中国地震局构造物理开放实验室,北京100029

出　　处：《地震地质》2004年第1期91-101,共11页Seismology and Geology

基　　金：地震科学联合基金 (1990 6 1)资助

摘　　要：根据先前相似模型实验的结果 ,在板块边界驱动下 ,沿岩石圈下层 (含下地壳和岩石圈地幔 )传播的塑性流动波包括“快波”和“慢波” ,二者均属于黏性重力波 ,并分别由主波和辅波叠加而成。“快波”以 10 0 ～ 10 2 km/a量级的速度传播 ,已为塑性流动波控制下地震迁移的研究所证实。文中根据 7级以上强震的条带状分布图像 ,证明在喜马拉雅弧驱动下还存在着波速仅为 10 0 ～ 10 1m/a量级的“慢波” ,其中对 7级以上强震起控制作用的主要是“慢波”的辅波 ,其平均波长为 4 45km ,波速为 0 81～ 2 80m/a ,周期为 0 .16～ 0 .5 5Ma。“慢波”的边界起波时间距今约 1.34～ 4 .6 6Ma ,相当于上新世中期至早更新世中期 ,与喜马拉雅构造运动的主要活跃期 (幕 )之一相吻合。以喜马拉雅弧西段和东段为波源所形成的2个“慢波”系统的波峰带相互重叠 ,为The results inferred from the experiments of analogue modeling carried out previously have shown that two types of plastic-flow waves, 'fast-wave' and 'slow-wave', are induced in the lower lithosphere (including the lower crust and lithospheric mantle) under the driving at plate boundary; and both of them are the viscous gravity waves formed by the superposition of major and subsidiary waves. The major one is similar to solitary wave and the subsidiary one is traveling wave. The plastic-flow waves in the lower lithosphere control the seismic activities in the overlying seismogenic layer and result in the distribution of earthquakes along the wave-crest belts. The 'fast-waves' propagated with velocities in the orders of magnitude of 10 0～10 2km/yr have been verified by the wave-controlled earthquake migration, showing the 'decade waves' and 'century waves' with the average periods of 10.8 and 93.4yr, respectively, which are originated from the Himalayan driving boundary. According to the recognition of the patterns of the belt-like distribution of strong earthquakes with M S≥7.0, it is indicated further in this paper that the 'slow-waves' with velocities in the orders of magnitude of 10 0～10 1m/yr are also originated under the compression from the Himalayan driving boundary. The strong earthquakes with M S≥7.0 are controlled mainly by the subsidiary waves, because the major waves with the duration up to 10 6yr for each perturbation are impossible to result in the accumulation of energy enough for generating strong earthquakes owing to the relaxation of the upper crust. The subsidiary waves propagate with an average wave length of 445km and, as estimated in term of the requirement of elastic energy for strong earthquakes in the crust (the constraint of energy for strong earthquakes) and the actual situation of the apparently immobile wave-crest belts (the constraint of the relative immobility of wave-crest belts), with velocities of 0.81～2.80m/yr and periods of 0.16～0.55Ma. The wave-generating t

关 键 词：岩石圈 塑性流动波 地震能量背景 强震 

分 类 号：P315.2[天文地球—地震学]