Long- and short-term deformation of convergent plate margins: Numerical modelling of seismic cycles at the South-Chilean oblique subduction zone

会聚板块边缘的长期和短期变形：南智利斜俯冲带地震周期的数值模拟

• 批准号: 87364802
• 负责人: Dr. Béatrice Cailleau
• 金额: --
• 依托单位: Sektion 4.1: Dynamik der Lithosphäre
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2008
• 资助国家: 德国
• 起止时间: 2007-12-31 至 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/87364802?language=en
• 关键词: Long; short; term; deformation; convergent

The subduction of the Nazca plate beneath the Southern Andes has resulted in several destructive historical earthquakes. These earthquakes appear to re-occur in cycles which, together with the oblique subduction direction, influence active deformation in the Chilean forearc and arc on different time scales. Although tectonic deformation is of high importance for hazard assessment, the relationship between the short-term and the long-term deformation of the upper plate is not well understood. The short-term deformation is related to transient elastic and viscous stresses that are released at earthquakes and the following decades. The long-term deformation, in contrast, is exhibited by permanent structures such as a strike-slip fault in the volcanic arc that accommodates northward migration of a forearc sliver, as well as basins and peninsulas in the forearc. This is a proposal to develop numerical models that incorporate self-running repeated earthquakes (seismic cycles) and the Theological heterogeneities of the plate margin with the goal to better understand the Andean crustal deformation on long- and short-term scales. We will investigate (a) the migration of the forearc and fault reactivation arising from oblique convergence, and (b) the addition and removal of material at the thrust interface that may be responsible for forearc basin and peninsula. These processes shall be combined and compared to GPS, gravimetric, seismic and geological data. The far-reaching goal of this study is to better identify the characteristics of the coupling at an oblique subduction thrust interface, and to test how the timing, size and location of earthquakes are linked to the short-term and the long-term crustal deformation.

纳斯卡板块在南安第斯山脉下的俯冲导致了几次破坏性的历史地震。这些地震似乎是在旋回中重复发生的，这些旋回与斜向俯冲方向一起，在不同的时间尺度上影响智利前弧和弧的活动变形。虽然构造变形对灾害评价具有重要意义，但对上板的短期和长期变形之间的关系尚不清楚。短期变形与地震及其后几十年释放的瞬态弹性和粘性应力有关。相比之下，长期变形表现为火山弧内的走滑断层等永久性构造，这些构造可容纳弧前银条的北移，以及弧前的盆地和半岛。为了更好地理解长期和短期尺度上的安第斯地壳变形，我们提出了一种结合自运行重复地震（地震循环）和板块边缘的神学非均质性的数值模型。我们将研究(a)斜辐合引起的前弧迁移和断层再活化，以及(b)冲断界面上可能导致前弧盆地和半岛形成的物质的添加和移除。这些过程应与GPS、重力、地震和地质数据相结合并进行比较。本研究的长远目标是更好地识别斜俯冲逆冲界面的耦合特征，并测试地震的时间、大小和位置如何与短期和长期地壳变形联系起来。