Source Estimation from Broadband Regional Seismograms
Source Estimation from Broadband Regional Seismograms
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发表时间：
1994-02
影响因子：
3
通讯作者：
Lian-She Zhao;D. Helmberger
中科院分区：
文献类型：
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作者：
Lian-She Zhao;D. Helmberger
最近发展的震源反演技术没有充分利用区域地震记录的宽带特性。这是因为由平层模型产生的绿色函数不能正确反映与实际地壳结构相关的复杂传播现象。反演通常通过去除短周期并仅反演记录的选定部分来执行。在这篇文章中，我们介绍了一个源估计技术，允许更好地利用整个宽带记录时，只有不完美的绿色的功能。该程序通过独立拟合部分绿色函数来降低主要地壳到达之间的时间敏感性。首选震源是使M_0、走向、倾角和倾角这四个参数的平均L1和L2范数最小的方位。L2误差强调较长周期的表面波，而L1误差加权较短周期的体波。我们通过对长周期和宽带信号进行建模来获得持续时间的估计。深度确定可以直接从表面反射相位sP_mP或sS_mS获得，或者通过循环通过深度相关的绿色函数获得。除了源参数，我们得到的“δt”相位对齐的变化，可以用来作为绿色的功能校正重新定位其他事件或作为一个指南，以获得新的地壳模型。
Recently developed source inversion techniques do not take full advantage of the broadband nature of regional seismograms. The reason is that Green's functions generated from flat-layered models are not correct for the complicated propagational phenomena associated with realistic crustal structure. The inversion is usually performed by removing short periods and inverting only selected portions of the records. In this article, we introduce a source estimation technique that allows for better use of the entire broadband record when only imperfect Green's function are available. The procedure desensitizes the timing between the principal crustal arrivals by fitting portions of the Green's functions independently. The preferred source is the orientation that minimizes the average L1 and L2 norms in term of the four parameters, M_0, strike, dip, and rake. The L2 error emphasizes the longer period surface waves while the L1 error weights the shorter period body waves. We obtain estimates of duration by modeling long period and broadband signals. The depth determination can be obtained directly from the surface reflected phases sP_mP or sS_mS or by cycling through the depth-dependent Green's functions. In addition to the source parameters, we obtain “δt” phase alignments shifts that can be used as Green's function corrections for relocating other events or as a guide to deriving new crustal models.