Characteristics and mechanisms of human‐induced earthquakes in China from the QuakeQuake database

Abstract

Based on the collation and collection of a large number of data, we construct an induced earthquake database, QuakeQuake, and report a total of 193 human‐induced earthquake cases in China. 155 human‐induced earthquakes in China recorded in the global‐induced earthquake database (HiQuake) are revisited and re‐arranged by compiling the Chinese literature. The human‐induced earthquakes in QuakeQuake database are classified into three levels of reliability, strong, moderate and weak levels, based on both human‐induced processes and seismic activity. Three main categories including reservoir‐induced earthquakes, mine‐induced earthquakes and other induced earthquakes in China are sorted based on data recording and types of the induced earthquakes. Most of the induced earthquakes with strong level in QuakeQuake database are mainly minor earthquakes (3 ≤ M < 4.5). The focal depth of reservoir‐induced and mining‐induced earthquakes is within 30 and 8 km deep, respectively. The active type of source faults of the large induced earthquakes is mainly thrust type with the highest proportion. The largest observed magnitude of the induced earthquakes (MMAX) correlates positively with the injection/extraction volume, reservoir dam heights, reservoir capacity and lithology of the reservoir area. Nine volume intervals corresponding to each induced earthquake type are figured out. Based on the analysis of the mechanisms of human‐induced earthquakes in China, the main mechanisms of surface mass loading are karst collapse or gas explosion, pore water pressure effect and gravity energy release. Underground material extraction is mainly induced by the compaction of different reservoirs. Two injection types of underground material are gas injection and water injection. Gas injection is related to continuous stress loading and unloading. Two induction mechanisms of water injection are the increase of fault pore pressure and the change of fault load condition.