The theory and method of relative location technique were described in the paper. The travel-time difference equa-tions for five phases (Pg, Sg, P11, S11 and Pn) were given. By using the multiplet relative location ap...The theory and method of relative location technique were described in the paper. The travel-time difference equa-tions for five phases (Pg, Sg, P11, S11 and Pn) were given. By using the multiplet relative location approach and wave correlation correction, the aftershock cluster of the Shunyi earthquake occurred on December 16, 1996 was relocated. The depth calculation was constrained by using multiple seismic phases. The relocation results were compared with that from traditional absolute location techniques.展开更多
The hydraulic fracture technique is widely applied in the enhancement of petroleum and natural gas productions and in the development of geothermal energy. This technique is also used to create an underground fracture...The hydraulic fracture technique is widely applied in the enhancement of petroleum and natural gas productions and in the development of geothermal energy. This technique is also used to create an underground fracture zone system for disposal of solid and liquid wastes. This is the most recent development in the application of industrial techniques to environmental protection scientific problems. Knowledge of mechanical properties and geometrical parameters of a hydraulic fracture zone is important for both energy resource development and safe disposal of waste. Hydraulic fracturing often induces many microearthquakes.Analysis of the spatial temporal distribution of the induced seismicity yields the geometry of a hydraulic fracture zone, and kinetic and dynamic parameters associated with the fracture growth process. Applying a waveform correlation analysis and a space time grid search method, we precisely determined hypocentral locations for 157 microearthquakes induced by hydraulic fracturing. Spatial distribution of the induced seismicity celarly shows the dimension and orientation of a hydraulic fracture zone. Variation of the seismicity distribution in time and space was used to infer the growth rate and direction of the fracture zone. An empirical Greens function(EGF) method was applied to earthquake doublets to retrieve relative source time functions(RSTFs) and to estimate source parameters, such as seismic moment, source radius, and stress drop, for larger microearthquakes. Azimuthal variation of the RSTF of a master event indicates that the source ruptured to the northwest, which aggrees with the fracture zone growth direction. Large variation of stress drops for these induced earthquakes reflects the significant heterogeneity of mechanical properties in the hydraulic fracture zone.展开更多
基金State Key Project of Science and Technology of China during the tenth five-year plan (2001BA601B02).
文摘The theory and method of relative location technique were described in the paper. The travel-time difference equa-tions for five phases (Pg, Sg, P11, S11 and Pn) were given. By using the multiplet relative location approach and wave correlation correction, the aftershock cluster of the Shunyi earthquake occurred on December 16, 1996 was relocated. The depth calculation was constrained by using multiple seismic phases. The relocation results were compared with that from traditional absolute location techniques.
文摘The hydraulic fracture technique is widely applied in the enhancement of petroleum and natural gas productions and in the development of geothermal energy. This technique is also used to create an underground fracture zone system for disposal of solid and liquid wastes. This is the most recent development in the application of industrial techniques to environmental protection scientific problems. Knowledge of mechanical properties and geometrical parameters of a hydraulic fracture zone is important for both energy resource development and safe disposal of waste. Hydraulic fracturing often induces many microearthquakes.Analysis of the spatial temporal distribution of the induced seismicity yields the geometry of a hydraulic fracture zone, and kinetic and dynamic parameters associated with the fracture growth process. Applying a waveform correlation analysis and a space time grid search method, we precisely determined hypocentral locations for 157 microearthquakes induced by hydraulic fracturing. Spatial distribution of the induced seismicity celarly shows the dimension and orientation of a hydraulic fracture zone. Variation of the seismicity distribution in time and space was used to infer the growth rate and direction of the fracture zone. An empirical Greens function(EGF) method was applied to earthquake doublets to retrieve relative source time functions(RSTFs) and to estimate source parameters, such as seismic moment, source radius, and stress drop, for larger microearthquakes. Azimuthal variation of the RSTF of a master event indicates that the source ruptured to the northwest, which aggrees with the fracture zone growth direction. Large variation of stress drops for these induced earthquakes reflects the significant heterogeneity of mechanical properties in the hydraulic fracture zone.
