Abstract In this paper, we introduce the theory of entropy using seismology. We use seismic data of 22 seismic stations in Sichuan seismic network. The permutation entropy is calculated in vertical components per hour, respectively. We study the temporal and spatial variation characteristics of the permutation entropy of ground motion before the MS8.0 Wenchuan earthquake and try to extract information about this earthquake. The results show that within 22 h before the Wenchuan earthquake, a high entropy area is formed near the epicenter. This high value area and the high value area on the north side of the Longmenshan fault system show a trend of wax and wane. The low value area on the east side of the epicenter stretches in the north-south direction, and bifurcates in the north-west direction of the epicenter. The Wenchuan earthquake occurs in the steep zone between the new high value zone and the low value zone. Combined with the findings of other scholars, we believe that these phenomena are likely to be related to the occurrence of the Wenchuan earthquake. Based on the temporal and spatial variation characteristics of the permutation entropy, we speculate that the earthquake is not only the result of the confrontation between the Bayan Har block and the Sichuan basin, but the movement of the Ordos block on the north side of the Longmenshan mountain fault system also participates in the seismogenic occurrence of the earthquake.
