1.Background on the seismic gap between the Wenchuan and the Lushan earthquakes rnThe 2008 Mw7.9 Wenchuan earthquake and the 2013 Mw6.9 Lushan earthquake, which occurred in the Longmenshan fault system (hereafter called LMSFS), caused dramatically casualties and huge economic losses.Their aftershock zones outline a seismic gap of about 50 km (Figure 1).Assuming that this Wenchuan-Lushan seismic gap (hereafter called WLSG) has a similar seismogenic structure to the source region of the Lushan earthquake, it has the ability to incubate an M7.0 earthquake.Thus, the seismic hazard in this gap is of great practical significance for scientific guidance of earthquake and disaster relief;at the same time, it can also be used as a reference for probing into other seismic gaps, such as the Daofu-Kangding gap along the Xianshuihe fault (Guo et al.,2020) and the Anninghe fault gap.