| 断裂带中古地震滑动的岩石记录 |
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| 关键词:fault rocks fast slip pseudotachylytes paleoearthquakes structural features |
| 基金项目:国家自然科学基金项目(编号: 41602226; 41830217);中国地质科学院基本科研业务费项目(编号: J1619; YYWF201601) |
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| Seismic Slip Records Preserved in Fault Rocks |
| A large number of field observations and experimental studies have demonstrated that the high strain rate deformation can cause special structures in the rocks. Some characteristic structures and mineral facies combination can be formed in the seismogenic zone and its adjacent rocks during an earthquake rupture process. Exhumed fault zones offer insights into deformation processes associated with earthquakes. Identifying the seismic slip signatures is of great importance for determining the paleoearthquakes and their faulting mechanisms. Cowan (1999) defined the pseudotachylyte, which is produced by the frictional melt during seismic slip, as the only reliable indicator of past earthquakes found in ancient faults. In recent years, significant progress in fault rock studies has revealed a range of reaction products which can be considered as seismic slip signatures, such as frictional devolatilization of carbonates and hydrous silicates, trance element mobility, maturation of organic material, fault mirrors, fluidized granular flow, clast-cortex aggregates, coseismic crystal plastic deformation and amorphous material. In addition, features formed under extreme transient stress conditions associated with propagating tip of an earthquake rupture, such as injection veins and pulverization can also be preserved in rocks as seismic records. Therefore, pseudotachylyte is no longer the only indicator of fossilized earthquake ruptures. Fault slip at rates in range 10–4–101 m/s is almost certainly dynamic, which means that features produced at rates as slow as 10–4 m/s in experiments may be tracers of seismic slip. The authors have summarized the rock records of seismic slip, which provide important information for learning the seismic fault mechanisms and complementing the earthquake theory. |
| WANG Huan,LI Hai-bing.2019.Seismic Slip Records Preserved in Fault Rocks[J].Acta Geoscientica Sinica,40(1):135-156. |
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