Invited by State Key Laboratory of Geodesy and Earth`s Dynamics (SKLGED), professor Leo Eisner from Institute of Rock Mechanics and Structures, Czech Academy of Sciences visited Institute of Geodesy and Geophysics(IGG) and gave two academic reports in title “The bedding plane sip model for microseismicity induced in shales” and “Hydraulic fracturing, induced seismicity and shale gas/oil” on June 7.

In his first report, professor Leo Eisner introduced the development history and fracture mode of shale gas water fracturing. He also explained four kinds of earthquake induced modes, such as rupture diffusion, fault loading, fracture extension and closure, and dip angle slip. Professor Leo Eisner combined with the ground and the underground seismic data inversion of the microseismic focal mechanism solution, the results showed that most of the earthquakes for high dip angle thrust or strike slip events. Then, he introduced a seismic model of regional water pressure that based on the inversion results of seismic source mechanism. He analyzed the influence of model error and data noise on the non-dual force couple component of the focal mechanism. The results showed that there was a certain non-dual force couple component in the hydraulic fracturing induced earthquake.

In his second report, professor Leo Eisner introduced several indexes that distinguish natural earthquakes from induced earthquakes, the relationship between the volume of water injection and the magnitude of induced earthquake studied by cross correlation method, and discussed the relationship between the increase of seismicity and wastewater treatment in the UK Blackpool and the US Oklahoma region. Furthermore, he put forward the concept of induced seismic traffic lights, shale gas extraction in the water injection and microseismic magnitude as a reference to reduce the possibility of a larger induced earthquake, so as to achieve the purpose of safe production.

Professor Leo Eisner received his Ph.D. in geophysics from California Institute of Technology in 2001. He is mainly engaged in High frequency asymptotic methods, forward modeling, inversion and uncertainty evaluation of full waveform 3D inhomogeneous media and so on.

                                       Professor Leo Eisner was giving his report.