A proposed study of the dynamics of the Hikurangi New Zealand margin.

拟对希库朗吉新西兰边缘的动态进行研究。

• 批准号: 1753660
• 负责人: Harlan Johnson
• 金额: $ 30万
• 依托单位: University of Washington
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-04-01 至 2022-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1753660&HistoricalAwards=false
• 关键词: proposed; study; dynamics; Hikurangi; New

This multi-disciplinary study will investigate the processes that trigger submarine slope failures on the New Zealand continental margin. The investigation will explore how many failures occur and their frequency, whether small landslides in an area make the slope resistant to large landslides, and what types of landslides generate tsunamis. Recent work off the northwest coast of the U.S. has shown that small landslides on continental margins occur more frequently than previously thought. The small landslides are caused by shaking generated by both local and remote earthquakes. Changes in the overlying water column were also found to be important in generating the small landslides. In this new study off New Zealand, seafloor sensor data will be combined with other available geophysical, water column, and meteorological data, to evaluate whether the results of the Cascadia work on the stability of submarine slopes can be generalized to other subduction zone margins. The results of this study will improve the capability to identify past large earthquakes in the sedimentary record. In addition, this study will provide constraints for models of submarine landslides and aid in predicting areas of potential slope failure. The study supports the training of a postdoctoral investigator.Accretionary margins that overlie active subduction zones undergo continuous re-surfacing by repeated sediment slope failures and gravity flows. Studies done off Cascadia show that slope failures can occur either spontaneously or be triggered by identifiable events that include oceanographic processes or by seismic waves generated by local or remote earthquakes. The mechanisms and key attributes of these triggering seismic waves (e.g., frequency content, duration, etc.) remain speculative. Preliminary results also indicate that the geologic structure and topography of the accretionary wedge have profound impacts on the seismic loading. Sediment slope failures and flows also can be triggered by storms, tides, upper water column eddies and circulation changes. This study tests these ideas by analyzing new data from seafloor sensors that were deployed on the Hikurangi margin off New Zealand in 2015. These data will also be used to examine the signature of slow slip events on the shallow plate interface. A Regional Ocean Modeling System hindcast will provide insight into the nature of signals at the seafloor that originate from ocean surface forcing in this area. By combining seafloor pressure, temperature and seismic ground motion measurements, with other available geophysical, water column and meteorological data, and the oceanographic context provided by the regional model, it will be possible to improve the fidelity of seafloor temperature and pressure signals associated with sediment slope failures and flows, with the side-benefit of characterizing near-surface eddies and ocean circulation changesThis award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

这项多学科研究将调查触发新西兰大陆边缘的潜艇斜率故障的过程。该调查将探索发生了多少故障和频率，是否在某个地区的小滑坡使坡度具有耐大量滑坡，以及哪种类型的滑坡会产生海啸。在美国西北海岸的最新工作表明，大陆边缘的小滑坡比以前想象的要频繁。小型滑坡是由当地和远程地震产生的摇动引起的。还发现上覆的水柱的变化对于产生小的滑坡很重要。在新西兰的这项新研究中，海底传感器数据将与其他可用的地球物理，水柱和气象数据相结合，以评估Cascadia在海底斜坡稳定性方面的工作结果是否可以推广到其他俯冲区的边缘。这项研究的结果将提高鉴定沉积记录中过去大地震的能力。此外，这项研究将为海底滑坡模型提供限制，并有助于预测潜在的坡度故障区域。该研究支持训练博士后研究者。覆盖活性俯冲带的良好边缘通过反复的沉积物斜率故障和重力流进行连续重新表演。在卡斯卡迪亚进行的研究表明，可以自发地发生斜率故障，也可以是由包括海洋学过程或局部或远程地震产生的地震波的可识别事件触发的。这些触发地震波（例如频率含量，持续时间等）的机制和关键属性仍然是推测性的。初步结果还表明，增生楔的地质结构和地形对地震载荷有深远的影响。沉积物斜率故障和流也可以由风暴，潮汐，上水柱涡流和循环变化触发。这项研究通过分析2015年在新西兰的Hikurangi余量上部署在海底传感器的新数据来测试这些想法。这些数据还将用于检查浅层板界面上慢滑动事件的签名。区域海洋建模系统的后广播将洞悉海底信号的性质，该信号源自该地区的海面强迫。通过将海底压力，温度和地震地面运动测量以及其他可用的地球物理，水柱和气象数据以及区域模型提供的海洋环境结合在一起，可以提高海底温度和压力信号的保真度，并与沉积物缝隙失败和流动相关，并颁发了近乎境内的埃德式循环，并授予了埃德式的循环循环。使用基金会的知识分子优点和更广泛的审查标准，通过评估被认为值得支持。