• 한국지구물리탐사학회:학술대회논문집
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• 2008.10a
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• pp.1-5
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• 2008

In and around the Korean Peninsula, 9 intraplate earthquake mechanisms since 1936 were analyzed to understand the regional stress orientation and tectonics. These earthquakes are largest ones in this century and may represent the characteristics of earthquake in this region. Focal mechanism of these earthquakes show predominant strike-slip faulting with small amount of thrust components. The average P-axis is almost horizontal ENE-WSW. This indicate that not only the subducting Pacific Plate but also the indenting Indian Plate controls earthquake mechanism in the far east of the Eurasian Plate.

• Journal of the Korean Geophysical Society
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• v.3 no.4
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• pp.245-250
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• 2000

By using amplitude ratios (SV/P, SH/P, SV/SH) and P and S wave polarities, we obtained fault plane solutions of the June 26, 1997 Kyong-ju earthquake. The solutions show $150{\pm}4^{\circ}$ in strike, $63{\pm}6^{\circ}$ in dip and $65{\pm}7^{\circ}$ in rake, or $18{\pm}12^{\circ}$ in strike, $26{\pm}3^{\circ}$ in dip and $120{\pm}5^{\circ}$ in rake. This result implies the stress field trending ENE-WSW, which is remarkably consistent with the previous results obtained from the moment tensor inversion, and from the composite fault plane solution for the events occurred around the Yangsan fault area.

• Geophysics and Geophysical Exploration
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• v.13 no.3
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• pp.198-202
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• 2010

In and around the Korean Peninsula, 18 intraplate earthquake focal mechanisms since 1936 were analyzed to understand the characteristic of focal mechanism and regional stress orientation and tectonics. These earthquakes are largest ones from the last century and may represent the characteristics of earthquake in this region. Focal mechanism of these earthquakes show predominant strike-slip faulting with small amount of thrust components. The average P-axis is almost horizontal ENE-WSW direction. This mechanism pattern and the direction of maximum stress axis is very similar with northeastern part of China and southwestern part of Japan. However they are quite different with the eastern part of East Sea. This indicate that not only the subducting Pacific Plate from east but also the indenting Indian Plate controls focal mechanism in the far east of the Eurasian Plate.

• Tunnel and Underground Space
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• v.23 no.6
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• pp.493-505
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• 2013

This numerical study investigates seismicity and fault slip induced by fluid injection in deep geothermal reservoir with pre-existing fractures and fault. Particle Flow Code 2D is used with additionally implemented hydro-mechanical coupled fluid flow algorithm and acoustic emission moment tensor inversion algorithm. The output of the model includes spatio-temporal evolution of induced seismicity (hypocenter locations and magnitudes) and fault deformation (failure and slip) in relation to fluid pressure distribution. The model is applied to a case of fluid injection with constant rates changing in three steps using different fluid characters, i.e. the viscosity, and different injection locations. In fractured reservoir, spatio-temporal distribution of the induced seismicity differs significantly depending on the viscosity of the fracturing fluid. In a fractured reservoir, injection of low viscosity fluid results in larger volume of induced seismicity cloud as the fluid can migrate easily to the reservoir and cause large number and magnitude of induced seismicity in the post-shut-in period. In a faulted reservoir, fault deformation (co-seismic failure and aseismic slip) can occur by a small perturbation of fracturing fluid (<0.1 MPa) can be induced when the injection location is set close to the fault. The presented numerical model technique can practically be used in geothermal industry to predict the induced seismicity pattern and magnitude distribution resulting from hydraulic stimulation of geothermal reservoirs prior to actual injection operation.