Collaborative Research: Towards an Understanding of the Collective Behavior of Regional Fault Networks: The Marlborough Fault System, New Zealand

合作研究：了解区域断层网络的集体行为：新西兰马尔堡断层系统

• 批准号: 1321914
• 负责人: James Dolan
• 金额: $ 35.96万
• 依托单位: University of Southern California
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-08-01 至 2018-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1321914&HistoricalAwards=false
• 关键词: Collaborative; Research; Towards; Understanding; Collective

The primary goal of this project is to determine how different faults in regional fault networks interact with one another to accommodate the relative motion of tectonic plates over time scales ranging from one to a few dozen earthquakes. The research team will focus on a particularly promising study area in northern South Island, New Zealand, where relative motions between the Pacific and Australian plates are partitioned amongst a set of four, parallel strike-slip faults known as the Marlborough fault system. Historical and paleo-earthquake data from the Marlborough fault system, which provides a useful analog for similar fault system elsewhere in the world (e.g., northern and southern California, Northwest Turkey, Hispaniola, parts of central and Southeast Asia, Iran-Pakistan), reveal tantalizing hints of complex earthquake occurrence, with possible temporal and spatial clustering of earthquakes that varies from cycle to cycle. But currently there are too few fault slip rate and paleo-earthquake age and displacement data to fully assess the collective spatial-temporal behavior of the Marlborough fault system. In order to document in detail how the four Marlborough faults share the tectonic plate motions, the research team will determine the rates of slip along each of these faults at a variety of time scales, ranging from a few to a few dozen earthquakes, as well as the ages and displacements of past earthquakes. Key to this effort will be the acquisition of about 300 square kilometers of high-resolution lidar digital topographic data from the four main Marlborough fault system faults. These data allow the efficiently mapping and measurement in unprecedented detail of fault offsets ranging from about 100 meters down to the smallest offsets that occurred in the most recent earthquakes. The Marlborough fault system is a particularly target-rich environment in this regard because many of the large fault-crossing rivers in the Marlborough region exhibit suites of river terrace edges that have been offset by variable amounts. Combining these offset features with age data from different geochronometers (radiocarbon and optically stimulated luminescence) will yield exceptionally detailed fault slip rates at a range of time scales from individual ruptures back though several dozen earthquakes. The researchers will also excavate trenches across the four faults to determine paleo-earthquake ages and displacements, allowing cross-correlation with the youngest slip rates. The resulting data, together with existing data and the results of ongoing studies by other groups, will allow documentation of the behavior of the Marlborough faults over a wide range of temporal and spatial scales, providing the information necessary for systematic comparison with the earthquake behavior of similar systems elsewhere in the world.The primary aim of this project is to advance understanding of the way regional networks of large faults store and release seismic energy, with a particular focus on determining the relative importance of so-called emergent phenomena such as clusters of large-magnitude earthquakes and periods of transiently elevated storage of seismic energy that may not be expected in the current understanding of earthquake physics and that are not accounted for in current seismic assessment strategies. The results will help the seismic hazard community to understand how regional fault networks distribute deformation in time and space - the keys to developing more accurate, next-generation seismic hazard assessment strategies, as well as the basis for future modeling efforts aimed at understanding the causes of such phenomena. This international effort will expand already strong scientific collaboration between the US researchers and their New Zealand collaborators, benefitting both groups by fostering increased interaction between the groups, both of which face similar seismic hazards in their respective countries. Specifically, in addition to working closely with seismic hazard planners at the US Geological Survey to ensure timely implementation of their results, the PIs are actively collaborating with colleagues at GNS Science, which is responsible for implementation of seismic hazard assessment in New Zealand, ensuring that the results of this project will be also incorporated into New Zealand's next-phase seismic hazard assessments.

该项目的主要目标是确定区域断层网络中不同的故障如何相互作用，以适应从一个到几十个地震范围内的构造板的相对运动。研究小组将重点关注新西兰北部北部岛上特别有前途的研究区域，在该区域中，太平洋和澳大利亚板之间的相对运动被分配给四个平行的滑移断层，称为Marlborough断层系统。来自马尔伯勒断层系统的历史和古耕种数据，为世界其他地方的类似断层系统提供了一个有用的类似物（例如，北加州和南加州，西北土耳其，土耳其西北，西班牙裔，西马西亚岛，中部和东南亚的部分，伊朗 - 巴基斯坦），揭示了与临时群体相处的诱人地震的诱人地震的诱人地震，并可能导致临时的周期。但是目前，断层滑移速率和古去Quake年龄和位移数据太少，无法充分评估Marlborough断层系统的集体时空行为。为了详细记录这四个马尔伯勒故障如何共享构造板块的动作，研究团队将在各种时间尺度上确定沿每个故障的滑动速率，从几个到几十个地震，以及过去地震的年龄和流离失所。这项工作的关键将是从四个主要的马尔伯勒故障系统故障的大约300平方公里的高分辨率激光雷达数字地形数据。这些数据允许有效地映射和测量故障偏移的细节，范围从约100米到最近发生的地震中发生的最小偏移。马尔伯勒断层系统在这方面是一个特别富裕的环境，因为马尔伯勒地区的许多大型断层跨河都表现出河露台边缘的套房，这些河流被可变数量所抵消。将这些偏移特征与来自不同地球体工程器的年龄数据（放射性碳和光刺激的发光）相结合，将在各个时间尺度上从单个破裂的范围内产生非常详细的断层滑移速率，但通过数十个地震。研究人员还将在四个故障上挖掘沟渠，以确定古Quake量的年龄和位移，从而使其与最年轻的滑移速率互相关。所得的数据以及现有数据以及其他小组正在进行的研究结果将允许在各种时间和空间量表上记录马尔伯勒故障的行为，从而提供了与世界其他地方的类似系统的地震行为进行系统比较所必需的信息。该项目的主要目标是促进大型网络的特定范围，以确保大型缺陷的范围，以确保释放Seeismiss网络，释放Seemiss的网络，以确定一个Seeismiss的网络，所谓的新出现现象，例如大型地震的簇和瞬时升高地震能量的时期，这些储存在当前对地震物理学的理解中可能无法预期，并且在当前的地震评估策略中尚未考虑。结果将有助于地震危害社区了解区域故障网络如何在时空分配变形 - 开发更准确，下一代的地震危害评估策略的关键，以及旨在了解这种现象原因的未来建模工作的基础。这项国际努力将扩大美国研究人员与他们的新西兰合作者之间已经有强有力的科学合作，从而通过促进两组之间的互动来使这两个群体受益，这两者在各自国家都面临着类似的地震危害。具体而言，除了在美国地质调查局与地震危险规划师紧密合作以确保其结果及时实施外，PI还与GNS Science的同事积极合作，该公司负责在新西兰实施地震危害评估，以确保该项目的结果还将被纳入新西亚西岛的下一个危险范围的危险中。