After the devastating Wenchuan earthquake on May 12, 2008, the Wenchuan earthquake Fault Scientific Drilling project (WFSD) was carried out in the eastern Tibetan Plateau, which is the most rapid scientific drilling response to large earthquakes in the world. The WFSD project provides an excellent opportunity for geoscientists to explore the formation mechanism of earthquakes. In total, 6 drilling boreholes were drilled along the Yingxiu-Beichuan and Guanxian-Anxian faults (Longmen Shan, China), which both ruptured during the Wenchuan earthquake. The WFSD project aims to reveal the composition, structure, morphology and tectonic properties of the Wenchuan earthquake fault zone at deep depths based on multi-disciplinary observations, measurements and analyses, to explore the physical and chemical behavior of the faults, their energy states, as well as their rupture processes during the Wenchuan earthquake. Thus, we aim to further understand the stress condition, the causes of nucleation and propagation of the rupture, the role of fluid in earthquake nucleation, propagation, and cessation, and the seismogenic mechanism of seismic faults. So far, some important research results have been achieved; (1) We know the structure of the Wenchuan earthquake fault zone. (2) We suggested that thermal pressurization was an important fault weakening mechanism during the Wenchuan earthquake, and that graphite in fault zone can be considered as an indicator to determine the occurrence of large earthquakes. (3) We obtained the lowest faults frictional coefficient in the world and recorded the information about fault healing quickly after this large earthquake for the first time. (4) We reconstructed the tectonic framework of the Longmen Shan and presented a new formation model of the Wenchuan earthquake. (5) We determined the spatial relationship between seismic activity and the different sections of the Longmen Shan thrust belt by accurately locating the aftershocks of the Wenchuan earthquake and by observing the seismic array near the boreholes, and revealed the relationship between the characteristics of fluid and seismic activities in the fault zone at deep depth, which provides the scientific basis for determining the formation process of large earthquakes.
