INVERSION OF GEODETIC DATA. PART II. OPTIMAL MODEL OF CONJUGATE FAULT SYSTEM FOR THE 1927 TANGO EARTHQUAKE
INVERSION OF GEODETIC DATA. PART II. OPTIMAL MODEL OF CONJUGATE FAULT SYSTEM FOR THE 1927 TANGO EARTHQUAKE
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大地测量数据的反演。
DOI：
10.4294/jpe1952.25.233
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发表时间：
1977
期刊：
影响因子：
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通讯作者：
M. Matsu'ura
中科院分区：
文献类型：
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作者：
M. Matsu'ura
利用前人（Part I； MATSU'URA, 1977）开发的“大地数据反演”方法分析了1927年探戈地震（M=7.5）引起的位移量变化，并获得了一组最优震源参数，用于共轭断层系统，即Gomura和Yamada。采用弹性半空间中由多个维度断层组成的多断层系统来模拟变形场，通过对地震断层周围的85个三角测量数据和25个找平数据进行逐次迭代反演，实现了模型参数的优化。得到的最佳断层参数为：高村断层D（位错）=3.7m, δ（三角角）=64°E, λ（滑动方向）=-8°，L（长度）=33km， W（宽度）=19km， D（深度）=0.4km, θ（断层走向）=N24°W；山田断层D=1.8m, δ=58°N, λ=120°，L=15km， W=9km， D= 0.2km, θ=N77°E，从断层平面上逆时针方向测量断层的滑动方向。这些结果表明，这两条地震断裂构成了一个由北西-东向单一应力系统引起的共轭断裂系统。编制了大地测量资料反演的计算机程序，利用该程序可从观测到的静位移资料中获得一套最优的地震和地震事件源参数。
Parmanent changes in displacement due to the 1927 Tango earthquake (M=7.5) are analyzed by using the method of "geodetic data inversion" developed in a previous paper (Part I; MATSU'URA, 1977), and a set of optimal source parameters is obtained for a system of conjugate faults, the Gomura and the Yamada.Deformation fields are modelled by a multiple-fault system composed of several dimensional faults in an elastic half-space, and the optimization of model parameters is accomplished through a process of successive iteration of inversions for 85 triangulation and 25 levelling data around the seismic faults.The optimal fault parameters obtained are D (dislocation)=3.7m, δ(dipangle)=64°E, λ(slip direction)=-8°, L(length)=33km, W(width)=19km, d(depth)=0.4km and θ(strike of fault)=N24°W for the Gomura fault, and D=1.8m, δ=58°N, λ=120°, L=15km, W=9km, d=0.2km and θ=N77°E for the Yamada fault, where the slip direction is measured counterclockwise from horizon on the fault plane. These results indicate that the two seismic faults constitute a system of conjugate faults caused by a single stress system of NW-SE compression.A computer program for the geodetic data inversion is completed, by which a set of optimal source parameters of seismic and aseismic events can be obtained from the observed static displacement data.