摘要
由光弹模拟实验得到的珠江三角洲及邻区的构造应力场反映出：①几乎所有断裂都呈压剪性应力状态，其端点、闭锁点都是应力集中点，应力集中系数为７—９。②部分ＮＷ向断裂的浅部呈张性应变状态，可发生张性破裂并引起４．５级以下的地震。③以１９６２年河源６．１级地震发生时的应力状态为标准考查现今应力场后发现，本区处于无大震的稳定状态，但河源若再发生５．９级以上地震，则意味着外场力增大并超过１９６２年的水平，区内ＮＷ和ＮＥＥ向断裂均有发生６级以上地震的可能。
The photoelastic simulation experiments on the structural field of stress in the PearlRiver delta and the area around have reflected that: 1 ) Almost all the falllts show pressureshearing stress state, the tips and lock spots are stress concentrated points at concentrationcoefficient 7-9; 2) The shallow portions of some of the NW-oriented faults show tensilestrain state, where tensile cracks may occur which may initiate earthquakes at weaker than4. 5 magnitude on Richter scale; 3) Taking the stress state happened during the magnitude6. 1 quake at Heyuan in 1962 as a basis, a sllrvey on the present field of stress shows thatthe region is in a steady state without strong earthquakes. However, put the case that anearthquake stronger than magnitude 5. 9 happens again in the heyuan area, then it signifiesthat the external force has upgraded to one stronger than that of the level in 1962, and theNW-/NEE-oriented faults in the region might possibly bring about quakes stronger thanmagnitude 6.
出处
《中国地震》
CSCD
北大核心
1994年第3期289-292,共4页
Earthquake Research in China
