Drivers and modulators of collisional tectonics and their impact on geohazards

碰撞构造的驱动因素和调节因素及其对地质灾害的影响

• 批准号: RGPIN-2015-04311
• 负责人: Grujic, Djordje
• 金额: $ 1.97万
• 依托单位: Dalhousie University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=681823
• 关键词: Drivers; modulators; collisional; tectonics; their

Understanding distribution of tectonic plate forces is key to predicting future earthquake activity around the globe. Although earthquakes mostly occur at tectonic plate edges due to the forces generated by relative movements of the plates, they can also be caused by remote forces, interior plate movements, and climatic effects that are poorly studied. Conventional plate tectonics assumes that mountain belts form by compression and thickening of Earth's crust along convergent plate margins. Yet theoretical and observational studies show that deformation also occurs in plate interiors. Collisional forces at mountainous boundaries oppose forces driving plate movement. This antagonism transmits stress into plate interiors, causing intraplate deformation and potentially leading to the disintegration of a plate. Conversely, breakup of a tectonic plate will reduce the amount of force transmitted to a collisional margin, influencing the amount of deformation and earthquake activity there. Although documented, these connections and feedback mechanisms remain unclear. *** The project's scientific contributions and long-term objectives will: 1) Develop a theory explaining how tectonic deformation is partitioned between plate margins and interiors; 2) Determine how plate-scale stress propagates from incipient breakup areas to collision zones; and 3) Ascertain whether distant forces influence stress along colliding plate boundaries. For this thematic research program, combining observational and theoretical framework, we chose to study the Himalayan region because (a) upper crustal deformation can be directly observed; (b) parameters controlling deformation and morphology of the fold-and-thrust belt are well established; (c) unidirectional moisture sources allow simpler investigation of climatic parameters; and (d) the Indian plate is currently deforming at suspected breakup zones within the Indian Ocean. *** The program proposes multiple hypotheses to be tested by multidisciplinary projects led by graduate students. Projects include compilation, synthesis and interpretation of seismic data; calculation of plate margin and plate interior forces; numerical simulations of orogenic wedge evolution; and detailed field studies. The distribution and magnitude of stresses in the Himalayan region is not merely an academic issue. A deeper understanding of stress propagation and deformation across the Himalaya will improve monitoring and prediction of seismic hazards. In broader terms, this program addresses potential dynamic links between subduction mega-earthquakes and stress loading within plates and along subduction margins around the world, including similar settings like the Cascadia of western Canada.**

了解构造板力的分布是预测全球未来地震活动的关键。尽管由于板的相对运动产生的力，地震主要发生在构造板边缘，但它们也可能是由远程力，内部板块运动和研究不足的气候效应引起的。常规板构造假定沿收敛板边缘的地壳压缩和增厚地壳形成山皮带。然而，理论和观察性研究表明，变形也发生在板内部。山区边界的碰撞部队反对驾驶板运动的力量。这种拮抗作用将应力传递到板内部，从而导致板内变形，并可能导致板的瓦解。相反，构造板的破裂将减少传递到碰撞边缘的力量，从而影响那里的变形和地震活动的量。尽管有记录，但这些连接和反馈机制仍不清楚。 ***该项目的科学贡献和长期目标将：1）开发一种理论，解释了如何在板缘和内部之间分配构造变形； 2）确定板尺度应力如何从初期分裂区域传播到碰撞区域； 3）确定远处是否影响沿碰撞板边界的应力。对于这个主题研究计划，结合了观测和理论框架，我们选择研究喜马拉雅地区，因为（a）可以直接观察到上皮变形； （b）控制褶皱带的变形和形态的参数已建立； （c）单向水分来源可以更简单地研究气候参数； （d）印度板目前在印度洋内的可疑分手区域变形。 ***该计划提出了由研究生领导的多学科项目对多个假设进行检验。项目包括地震数据的汇编，合成和解释；板缘和板内部力的计算；造山学楔的演化的数值模拟；和详细的现场研究。喜马拉雅地区的压力分布和大小不仅是一个学术问题。对喜马拉雅山脉的压力传播和变形的更深入了解将改善对地震危害的监测和预测。从更广泛的角度来看，该计划介绍了俯冲巨型地震与板内的压力载荷之间的潜在动态联系，以及世界各地的俯冲边缘，包括类似的环境，例如加拿大西部的卡斯卡迪亚。**