澜沧江断裂带环境剪应力场与地震活动分析

Relationship between Seismicity and Environmental Shear Stress Field along Lancangjiang Fault Zone

利用地震波资料，测算了1990～2003年沿澜沧江断裂带上中小地震震源处的相对剪应力强度值，分析了该断裂带环境剪应力场的空间分布及其与地震活动的关系。结果表明，澜沧江断裂带总体上处于环境剪应力场的相对低值分布区，但在断裂带局部段落及其附近出现一定时段的高剪应力值分布，这主要是受断裂带附近区域高剪应力状态的影响。沿澜沧江断裂带地震活动性较弱，这与沿断裂带环境剪应力场的低值状态基本一致。

The equivalent shear stress strengths are calculated at the foci of the mid-small earthquakes in 1990-2003 along the Lancangjiang fault zone based on the seismic wave data. The result shows that the Lancangjiang fault zone is in the low stress region of environmental shear stress field in general, only in some local sections and vicinities of the fault zone distribute high stress values due to being effected by the high shear stress status nearby the zone. The seismic activity is weak along the Lancangjiang fault zone, which is consistent with the low value status of the shear stress field.