Abstract: The fluids play an important role in the seismicity cycle of fault zones. The authors put forward several research areas that should be strengthened in the near future in China; ① Fault permeability structure and pale-geohydrological history of fault zone; ② The scale effect on fluid movement along fault zones; ③ The relationship between fluid circulation distribution and tectonic geometry; ④ The relationship between the shallow and the deep fluids. It is suggested that a systemic research work should be done on a specific earthquake fault, and the following topics should be studied preferentially. These are: ① What is the origin and composition of fault zone fluids? ② Identify the range of conditions necessary to develop and maintain elevated fluid pressures; ③ What are the fluid transport mechanisms in and around the fault zone and what physical processes lead to fluid redistribution? ④ Quantify pore pressure spectrum of fault; ⑤ What is the vertical and lateral distribution of fluid pressure regimes; ⑥ What is extent of vertical and lateral fluid migration and pore pressure during a seismic stress cycle?

Key words: Seismological fluid, Fault permeability structure, Pale-geohydrology, Scale effect