The October 17, 1989, Loma Prieta, California, Earthquake and its aftershocks: Geometry of the sequence from high-resolution locations
The October 17, 1989, Loma Prieta, California, Earthquake and its aftershocks: Geometry of the sequence from high-resolution locations
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DOI：
10.1029/gl017i009p01417
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发表时间：
1990-08
影响因子：
5.2
通讯作者：
L. Dietz;W. Ellsworth
中科院分区：
文献类型：
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作者：
L. Dietz;W. Ellsworth
洛马普列塔序列的震源形成一个倾斜带，从主震震源上升，并平行于主震节面。大多数余震聚集在地震带的周边，围绕着一个相对平静的中心，这个中心接近主震破裂的区域。在它的东南端，倾斜的余震区扭曲成一个垂直的表面，对应于圣安德烈亚斯断层。在地震带的中部和西北部，深度超过1000公里，余震形成了许多不相交的断层结构。在这一事件中观察到的反向滑动的大分量与在挤压断层弯曲内的倾斜平面上的滑动的简单模型一致。我们不认为洛马普列塔地震发生在萨金特断层上。然而，我们无法断定它是否破坏了主要的板块边界断层或不太频繁的活动断层。
Hypocenters of the Loma Prieta sequence form a dipping zone that rises from the mainshock hypocenter and is parallel to the mainshock nodal plane. Most aftershocks cluster around the perimeter of the zone, surrounding a relatively aseismic center which approximates the region of mainshock rupture. At its southeastern end, the dipping aftershock zone warps into a vertical surface that corresponds to the San Andreas fault. In the central and northwestern parts of the zone at depths above ∼10 km, the aftershocks define numerous disjoint fault structures. The large component of reverse-slip observed in this event agrees with a simple model for slip on a dipping plane within a compressional fault bend. We do not believe that the Loma Prieta earthquake occurred on the Sargent fault. However, we are unable to conclude whether it ruptured the principal plate boundary fault or a less frequently active fault.