Methods for inversion of body-wave waveforms for localized three-dimensional seismic structure and an application to D" structure beneath Central America
Methods for inversion of body-wave waveforms for localized three-dimensional seismic structure and an application to D" structure beneath Central America
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DOI：
10.1093/gji/ggt520
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发表时间：
2014-04-01
影响因子：
2.8
通讯作者：
Fuji, Nobuaki
中科院分区：
文献类型：
--
作者：
Kawai, Kenji;Konishi, Kensuke;Fuji, Nobuaki
我们制定的波形反演的反问题，局部三维地震结构，计算偏导数的波形相对于弹性模量在空间中的任意点的各向异性和滞弹性介质。在这项研究中，我们最大限度地减少计算要求，通过使用玻恩近似相对于一个横向均匀的模型，但这不是我们的方法的固有限制。我们使用共轭梯度（CG）方法求解反问题，使用赤池信息准则（AIC）截断CG展开。我们应用我们的方法来反演的3-D剪切波结构在最低的地幔中美洲使用的周期从12.5到200秒记录在北美太平洋沿岸附近的站点为29个深，中深度的事件南美洲下面的2154波形。由此产生的模型显示在E-W方向的横向不均匀性，这可能与俯冲冷板包围较热的材料与较慢的速度。各种测试表明，我们的模型是强大的。
We formulate the inverse problem of waveform inversion for localized 3-D seismic structure, computing partial derivatives of waveforms with respect to the elastic moduli at arbitrary points in space for anisotropic and anelastic media. In this study we minimize computational requirements by using the Born approximation with respect to a laterally homogeneous model, but this is not an inherent limitation of our approach. We solve the inverse problem using the conjugate gradient (CG) method, using Akaike's Information Criterion (AIC) to truncate the CG expansion. We apply our method to invert for 3-D shear wave structure in the lowermost mantle beneath Central America using a total of 2154 waveforms at periods from 12.5 to 200 s recorded at stations near the Pacific coast of North America for 29 deep and intermediate-depth events beneath South America. The resulting model shows lateral heterogeneity in the E-W direction, which may be associated with a subducted cold slab surrounded by hotter materials with slower velocities. Various tests show that our model is robust.