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

这项多学科研究将调查在新西兰大陆边缘引发海底斜坡破坏的过程。调查将探讨发生了多少次山体滑坡及其频率，一个地区的小型山体滑坡是否能使斜坡抵抗大型山体滑坡，以及哪种类型的山体滑坡会引发海啸。美国西北海岸最近的研究表明，大陆边缘的小型山体滑坡发生的频率比之前认为的要高。这些小型山体滑坡是由本地和远程地震引起的震动引起的。上覆水柱的变化也被发现是导致小型山体滑坡的重要原因。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，以评估卡斯卡迪亚关于海底斜坡稳定性的工作结果是否可以推广到其他俯冲带边缘。这项研究的结果将提高识别沉积记录中过去的大地震的能力。此外，这项研究将为海底滑坡模型提供约束，并有助于预测潜在的斜坡失稳区域。这项研究支持博士后研究人员的培训。覆盖在活动俯冲带上的增量边缘经历了反复的沉积物、斜坡破坏和重力流而不断地重新浮出水面。在卡斯卡迪亚进行的研究表明，斜坡崩塌可以自发发生，也可以由可识别的事件触发，包括海洋过程，或者由本地或远程地震产生的地震波触发。这些触发地震波的机制和关键属性(例如，频率内容、持续时间等)保持投机性。初步结果还表明，沉积楔体的地质结构和地形对地震荷载有深刻的影响。风暴、潮汐、上层水柱漩涡和环流变化也可能触发泥沙坡面失稳和水流。这项研究通过分析2015年部署在新西兰近海Hikurangi边缘的海底传感器的新数据来测试这些想法。这些数据还将被用来研究浅板块界面上的慢滑事件的特征。区域海洋模拟系统后播将深入了解这一区域海洋表面强迫产生的海底信号的性质。通过将海底压力、温度和地震地面运动测量与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学背景相结合，将有可能提高与沉积物坡度破坏和流动有关的海底温度和压力信号的保真度，同时还可以获得表征近地表涡流和海洋环流变化的附带好处。

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.