SUMMARY We present PRISM3D, a 3-D reference seismic model of P- and S-wave velocities for Iberia and adjacent areas. PRISM3D results from the combination of the most up-to-date earth models available for the region. It extends horizontally from 15°W to 5°E in longitude, 34°N to 46°N in latitude and vertically from 3.5 km above to 200 km below sea level, and is modelled on a regular grid with 10 and 0.5 km of grid node spacing in the horizontal and vertical directions, respectively. It was designed using models inferred from local and teleseismic body-wave tomography, earthquake and ambient noise surface wave tomography, receiver function analysis and active source experiments. It includes two interfaces, namely the topography/bathymetry and the Mohorovičić (Moho) discontinuity. The Moho was modelled from previously published receiver function analysis and deep seismic sounding results. To that end we used a probabilistic surface reconstruction algorithm that allowed to extract the mean of the Moho depth surface along with its associated standard deviation, which provides a depth uncertainty estimate. The Moho depth model is in good agreement with previously published models, although it presents slightly sharper gardients in orogenic areas such as the Pyrenees or the Betic-Rif system. Crustal and mantle P- and S-wave wave speed grids were built separately on each side of the Moho depth surface by weighted average of existing models, thus allowing to realistically render the speed gradients across that interface. The associated weighted standard deviation was also calculated, which provides an uncertainty estimation on the average wave speed values at any point of the grid. At shallow depths (<10 km), low P and S wave speeds and high VP/VS are observed in offshore basins, while the Iberian Massif, which covers a large part of western Iberia, appears characterized by a rather flat Moho, higher than average VP and VS and low VP/VS. Conversely, the Betic-Rif system seems to be associated with low VP and VS, combined with high VP/VS in comparison to the rest of the study area. The most prominent feature of the mantle is the well known high wave speed anomaly related to the Alboran slab imaged in various mantle tomography studies. The consistency of PRISM3D with previous work is verified by comparing it with two recent studies, with which it shows a good general agreement.The impact of the new 3-D model is illustrated through a simple synthetic experiment, which shows that the lateral variations of the wave speed can produce traveltime differences ranging from –1.5 and 1.5 s for P waves and from –2.5 and 2.5 s for S waves at local to regional distances. Such values are far larger than phase picking uncertainties and would likely affect earthquake hypocentral parameter estimations. The new 3-D model thus provides a basis for regional studies including earthquake source studies, Earth structure investigations and geodynamic modelling of Iberia and its surroundings.

中文翻译：

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PRISM3D：伊比利亚和邻近地区的 3-D 参考地震模型

总结 我们提出了 PRISM3D，它是伊比利亚和邻近地区的 P 波和 S 波速度的 3D 参考地震模型。PRISM3D 结合了该地区可用的最新地球模型。它水平从西经 15° 到东经 5°，在纬度从 34°N 到 46°N，垂直从海平面以上 3.5 公里到海平面以下 200 公里，并以 10 和 0.5 公里网格的规则网格为模型分别在水平和垂直方向上的节点间距。它是使用从局部和远震体波层析成像、地震和环境噪声表面波层析成像、接收器功能分析和有源源实验推断的模型设计的。它包括两个界面，即地形/水深测量和 Mohorovičić (Moho) 不连续性。Moho 是根据先前发表的接收函数分析和深度地震探测结果建模的。为此，我们使用了一种概率表面重建算法，该算法允许提取莫霍面深度表面的平均值及其相关的标准偏差，从而提供深度不确定性估计。Moho 深度模型与先前发布的模型非常一致，尽管它在比利牛斯山脉或 Betic-Rif 系统等造山带地区呈现出稍微更清晰的方向。地壳和地幔 P 波和 S 波速度网格通过现有模型的加权平均在 Moho 深度表面的每一侧分别构建，从而可以真实地渲染跨该界面的速度梯度。还计算了相关的加权标准偏差，它提供了对网格任何点的平均波速值的不确定性估计。在浅水深度（<10 km），在近海盆地观察到低 P 和 S 波速度和高 VP/VS，而覆盖伊比利亚西部大部分地区的伊比利亚地块似乎以相当平坦的莫霍面为特征，较高的比平均 VP 和 VS 和低 VP/VS。相反，与研究区域的其他部分相比，Betic-Rif 系统似乎与低 VP 和 VS 以及高 VP/VS 相结合。地幔最突出的特征是众所周知的高波速异常，该异常与在各种地幔层析成像研究中成像的 Alboran 板片有关。通过将 PRISM3D 与最近的两项研究进行比较，验证了 PRISM3D 与先前工作的一致性，并显示出良好的总体一致性。新 3-D 模型的影响通过一个简单的合成实验来说明，该实验表明波速的横向变化可以产生 P 波的 –1.5 和 1.5 s 以及 S 波的 –2.5 和 2.5 s 的走时差异本地到区域距离的波浪。这些值远大于相位选择的不确定性，可能会影响地震震源参数估计。因此，新的 3-D 模型为区域研究提供了基础，包括伊比利亚及其周边地区的地震源研究、地球结构调查和地球动力学建模。这些值远大于相位选择的不确定性，可能会影响地震震源参数估计。因此，新的 3-D 模型为区域研究提供了基础，包括伊比利亚及其周边地区的地震源研究、地球结构调查和地球动力学建模。这些值远大于相位选择的不确定性，可能会影响地震震源参数估计。因此，新的 3-D 模型为区域研究提供了基础，包括伊比利亚及其周边地区的地震源研究、地球结构调查和地球动力学建模。