Abstract Understanding how long-term subduction dynamics relates to the short-term seismicity and crustal tec tonics is a challenging but crucial topic in seismotectonics. We attempt to address this issue by linking long-term geodynamic evolution with short-term seismogenic deformation in the Northern Apennines. This retreating subduction orogen displays tectonic and seismogenic behaviors on various spatiotemporal scales that also characterize other subduction zones in the Mediterranean area. We use visco-elasto-plastic seismo-thermo-mechanical (STM) modeling with a realistic 2D setup based on available geological and geophysical data. The subduction dynamics and seismicity are coupled in the numerical modeling, and driven only by buoyancy forces, i.e., slab pull. Our results suggest that lower crustal rheology and lithospheric mantle temperature modulate the crustal tectonics of the Northern Apennines, as inferred by previous studies. The observed spatial distribution of upper crustal tectonic regimes and surface displacements requires buoyant, highly ductile material in the subduction channel beneath the internal part of the orogen. This allows protrusion of the asthenosphere in the lower crust and lithospheric delamination associated with slab retreat. The resulting surface velocities and principal stress axes generally agree with present-day observations, suggesting that slab delamination and retreat can explain the dynamics of the orogen. Our simulations successfully reproduce the type and overall distribution of seismicity with thrust faulting events in the external part of the orogen and normal faulting in its internal part. Slab temperatures and lithospheric mantle stiffness affect the cumulative seismic moment release and spatial distribution of upper crustal earthquakes. The properties of deep, sub-crustal material are thus shown to influence upper crustal seismicity in an orogen driven by slab retreat, even though the upper crust is largely decoupled from the lithospheric mantle. Our simulations therefore highlight the effect of deep lower crustal rheologies, self-driven subduction dynamics and mantle properties in controlling shallow deformation and seismicity.

中文翻译：

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板块退缩和岩石圈分层驱动的北亚平宁山脉构造和地震活动

摘要 了解长期俯冲动力学与短期地震活动和地壳构造运动的关系是地震构造学中一个具有挑战性但至关重要的课题。我们试图通过将长期地球动力学演化与北亚平宁山脉的短期地震变形联系起来来解决这个问题。这种后退的俯冲造山带在各种时空尺度上显示出构造和地震行为，这也是地中海地区其他俯冲带的特征。我们使用粘弹塑性地震热机械 (STM) 建模和基于可用地质和地球物理数据的真实 2D 设置。俯冲动力学和地震活动在数值模拟中是耦合的，并且仅由浮力驱动，即板块拉力。我们的研究结果表明，正如先前研究所推断的那样，下地壳流变学和岩石圈地幔温度调节了北亚平宁山脉的地壳构造。观察到的上地壳构造制度和地表位移的空间分布需要在造山带内部下方的俯冲通道中有浮力、高延展性的物质。这使得下地壳中的软流圈突出和与板块后退相关的岩石圈分层。由此产生的表面速度和主应力轴与目前的观察结果基本一致，表明板块分层和后退可以解释造山带的动力学。我们的模拟成功地再现了地震活动的类型和总体分布，其中包括造山带外部的逆冲断层事件和内部的正断层事件。板块温度和岩石圈地幔刚度影响上地壳地震的累积地震矩释放和空间分布。因此，即使上地壳在很大程度上与岩石圈地幔分离，但深层、亚地壳物质的特性显示出影响由板块后退驱动的造山带中的上地壳地震活动。因此，我们的模拟突出了深部下地壳流变学、自驱动俯冲动力学和地幔特性在控制浅层变形和地震活动中的作用。板块温度和岩石圈地幔刚度影响上地壳地震的累积地震矩释放和空间分布。因此，即使上地壳与岩石圈地幔在很大程度上脱钩，深部亚地壳物质的特性仍会影响由板块后退驱动的造山带中的上地壳地震活动。因此，我们的模拟突出了深部下地壳流变学、自驱动俯冲动力学和地幔特性在控制浅层变形和地震活动中的作用。板块温度和岩石圈地幔刚度影响上地壳地震的累积地震矩释放和空间分布。因此，即使上地壳与岩石圈地幔在很大程度上脱钩，深部亚地壳物质的特性仍会影响由板块后退驱动的造山带中的上地壳地震活动。因此，我们的模拟突出了深部下地壳流变学、自驱动俯冲动力学和地幔特性在控制浅层变形和地震活动中的作用。