地震主应力方向的附加潮汐应力计算及其对发震断层的作用方式研究

通过对地震震源处沿主压应力P轴和主张应力T轴方向的附加潮汐应力分量的计算，在岩石力学莫尔－库化准则的基础上分析了附加潮汐应力对发震断层的作用方式。分析和计算表明，对发震断层有促滑作用的附加潮汐应力作用方式分增压型和减压型，增压型潮汐应力增大断层面上的正压力和剪应力，促使断层达到破裂滑动条件，减压型潮汐应力在一定条件下能降低断层面上的破裂滑动强度，同样能促使断层的运动。计算实例显示，大部分发震断层受到了附加潮汐应力的增压型或减压型促滑作用。

Calculation of Additional Tidal Stress along Seismic Pr inciple Stress Orientation and Study on its Action Mode on Seismogenic Fault

Through calculating additional tidal stress component along the P axis of principle compressional stress and the T axis of principle extensional stress at source,the action mode of additional tidal stress on seismogenic fault is analyzed on the basis of Mohr-Coulomb criterion.Analysis and calculation show that the action mode of additional tidal stress on seismogenic fault can be classified as compression increase and compression decrease;the tidal stress for compression increase increases normal pressure and shear stress on the fault plane,which makes the fault be in the state of rupture and slip;the tidal stress for compression decrease can decrease rupture-slip strength on the fault plane under given conditions and also promote the fault's motion.the calculation example shows slip-promoting action of pressure increase or decrease mode of additional tidal stress on the most of seismogenic faults.