We estimated the areas exhibiting high‐frequency (⁠1∼10 Hz⁠) wave radiation on the fault plane of the 2008 Wenchuan earthquake, by applying envelope inversion to strong‐motion acceleration records. The corrected records of two small earthquakes are adopted as the empirical Green’s functions. Considering the change in the rupture pattern of the Wenchuan earthquake from southwest to northeast, the records of small earthquakes dominated by thrust and strike‐slip are utilized as the empirical Green’s function for the southwestern and northeastern fault sections, respectively. The results are as follows: (1) According to the high‐frequency wave radiation, the rupture process is complex. High‐frequency waves radiated strongly in six areas: around the initial rupture point, along the north and south edges of the fault plane, near the area of intersection with the cross‐cutting Xiaoyudong fault, south of Nanba, and near the area of Qingchuan. In total, these areas can be divided into three cases. In the first situation, high‐frequency waves radiated strongly around the initial rupture area, which may be associated with the initiation of rupture and a high stress drop. The second location is near the periphery of the fault, which is associated with the termination of rupture. The third condition comprises high‐frequency waves near the intersection with the cross‐cutting Xiaoyudong fault. This area as a geometric barrier, and the surface rupture is observed. (2) The distribution patterns of the high‐ and low‐frequency radiation intensity differ on the fault plane. From the hypocenter to the point of intersection with the Xiaoyudong fault, the high‐frequency wave is located around the area with large slip value. In other areas, the distribution of the high‐ and low‐frequency radiation is no obvious relationship. This different characteristic indicates the complexity of the rupture process.

中文翻译：

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用包络反演估算2008年汶川7.9级地震断层面上的高频波辐射面积。

通过将包络反演应用于强运动加速度记录，我们估计了在2008年汶川地震断层平面上展现出高频（⁠1〜10Hz⁠）波辐射的区域。将两次小地震的校正记录用作格林的经验函数。考虑到汶川地震的破裂方式从西南向东北变化，分别以西南和东北断裂带的经验格林函数作为推力和走滑为主的小地震记录。结果如下：（1）根据高频波辐射，破裂过程很复杂。高频波在六个区域强烈辐射：围绕初始破裂点，沿断层平面的南北边缘，南坝以南，青川地区附近的小玉洞断层交汇处附近。总的来说，这些区域可以分为三种情况。在第一种情况下，高频波在初始破裂区域附近强烈辐射，这可能与破裂的开始和较高的应力降有关。第二位置靠近断层的外围，这与破裂的终止有关。第三个条件是与横贯的小鱼洞断层相交处附近的高频波。该区域为几何屏障，并且观察到表面破裂。（2）断层平面上高频和低频辐射强度的分布模式不同。从震源到与小鱼洞断裂的交点，高频波位于滑动值较大的区域附近。在其他地区，高频和低频辐射的分布没有明显的关系。这种不同的特征表明了破裂过程的复杂性。