We use 3D dynamic rupture simulations to discover a previously un-described effect of asymmetric topography on the earthquake process. With the Cajon Pass along the San Andreas Fault as an example, we find that asymmetric topography generates an alternating normal stress perturbation around the rupture front, near the free surface. When topography lies to the right of the propagating right-lateral front, the normal stress perturbation is clamping ahead of the rupture front and unclamping behind. When topography alternates to the left, the perturbation reverses sign. The process is analogous to the normal stress variations on dip-slip faults. While this effect does not strongly affect rupture propagation and slip in our current parametrization, it requires explanation and exploration. An understanding of the normal stress perturbation due to asymmetric topography will help prevent its misattribution to other sources and lead to a better understanding of the interplay of multiple processes during earthquakes.

中文翻译：

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不对称地形导致断裂前沿的法向应力扰动：Cajon Pass 的案例

我们使用 3D 动态破裂模拟来发现先前未描述的非对称地形对地震过程的影响。以沿圣安德烈亚斯断层的卡洪山口为例，我们发现非对称地形在自由表面附近的破裂前沿周围产生交替的法向应力扰动。当地形位于传播的右侧前缘的右侧时，正应力扰动在破裂前缘之前夹紧并在后面松开。当地形向左交替时，扰动反转符号。该过程类似于倾滑断层上的正应力变化。虽然这种效应在我们目前的参数化中不会强烈影响破裂传播和滑动，但它需要解释和探索。