Architecture of the Subduction to Strike-Slip Transition in New Zealand

新西兰俯冲到走滑过渡的结构

• 批准号: 1756075
• 负责人: Clifford Thurber
• 金额: $ 27.51万
• 依托单位: University of Wisconsin-Madison
• 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: 2018-03-15 至 2024-02-29
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1756075&HistoricalAwards=false
• 关键词: Architecture; Subduction; Strike; Slip; Transition

In recent years, seismologists have come to recognize that many large earthquakes that occur involve slip on multiple faults. This phenomenon means that estimates of earthquake hazard based on the assumption that faults fail individually can underestimate the size of the largest possible earthquake in a region, and in turn the level of seismic hazard. The November 14, 2016 magnitude 7.8 Kaikoura earthquake in the northern South Island, New Zealand, stands out as one of the most complex earthquakes known, with rupture of the ground surface observed on more than 20 faults. The earthquake was followed by tens of thousands of aftershocks, and it also triggered a number of what are called "slow slip events" - fault slip occurring over days to months instead of seconds to minutes like most earthquakes. The Kaikoura earthquake is the latest in a series of damaging earthquakes in the northern part of the South Island in New Zealand that have struck in this decade. This project will examine several key questions related to the complicated geologic evolution of this region. This project will take advantage of data and results from a broad range of studies that have been carried out over the past two decades. It will also utilize seismic data from temporary arrays that were deployed to record aftershock and were operated, in part, with support of RAPID funding from NSF. The tasks of this project are to image the three-dimensional seismic velocity and attenuation structure, to relocate earthquakes that occurred in the region with high-precision, and to determine the fault slip geometry using the aftershock locations. This work will contribute to our understanding of how multiple-fault failure occurs in large earthquakes, thereby contributing to improving seismic hazard estimation. The work will be carried out in close collaboration with New Zealand scientists from GNS Science and Victoria University of Wellington. In addition, as part of the broader impacts, this project will mentor a female postdoctoral scholar.The November 14, 2016 Mw 7.8 Kaikoura earthquake in the northern South Island, New Zealand, stands out as one of the most complex seismic events known. Surface rupture has been mapped on at least 21 faults. Post-seismic slow slip events were triggered over a broad area, including substantial slip on the South Island megathrust underlying the activated crustal faults. The Kaikoura earthquake is the latest in a series of damaging earthquakes in the Canterbury and Marlborough regions of the South Island that have struck in this decade, starting with the Darfield and Christchurch earthquakes of 2010 and 2011, continuing with the Seddon and Lake Grassmere earthquakes of 2013, and culminating in the 2016 Kaikoura earthquake. We note that the Mw 7.1 Darfield earthquake was also a complex, multi-fault rupture.This project will examine several hypotheses related to the complex tectonics of this region of transition from subduction to strike-slip. The proposed study will take advantage of data and results from a broad range of studies that have been carried out in this region over the past two decades, and utilize data from temporary aftershock arrays supported in part by NSF through RAPID awards. The main analysis tools are seismic velocity and attenuation tomography that incorporate recent and planned methodological developments, high-precision earthquake relocation, and focal mechanism analysis. The work will be carried out in close collaboration with New Zealand scientists from GNS Science and Victoria University of Wellington and will engage a female postdoctoral scholar in the data analysis and interpretation.This 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.

近年来，地震学家已经认识到，发生的许多大地震都涉及多个断层。这种现象意味着，基于假设单独失败的假设可以估计地震危害，这可能会低估该地区最大的地震的大小，进而又可能低估地震危险的水平。 2016年11月14日，在新西兰北部北部岛上的7.8 kaikoura地震是已知的最复杂的地震之一，在20多个断层上观察到地面破裂。地震之后是成千上万的余震，它还触发了许多所谓的“慢速事件” - 几天到几个月发生的断层滑移，而不是像大多数地震一样秒到几分钟。 Kaikoura地震是新西兰南岛北部一系列破坏性地震中的最新地震，这些地震袭击了这十年。该项目将研究与该地区复杂的地质演化有关的几个关键问题。该项目将利用过去二十年来进行的广泛研究的数据和结果。它还将利用部署的临时阵列中的地震数据来记录余震，并在一定程度上在NSF的快速资金支持下进行操作。该项目的任务是对三维地震速度和衰减结构进行成像，以重新定位具有高精度区域中发生的地震，并使用余震位置确定断层滑移几何形状。这项工作将有助于我们理解大地震中多发性故障的发生，从而有助于改善地震危险估计。这项工作将与GNS科学和惠灵顿维多利亚大学的新西兰科学家密切合作。此外，作为更广泛影响的一部分，该项目将指导一位女性博士后学者。2016年11月14日MW 7.8 Kaikoura地震在新西兰北部北部岛，是最复杂的地震事件之一。表面破裂已在至少21个故障上映射。在广阔的区域上触发了断电后的慢滑动事件，包括在激活的地壳断层的基础上的大量滑移。 Kaikoura地震是南岛坎特伯雷和马尔伯勒地区一系列破坏性地震中的最新地震，从2010年和2011年的Darfield和Christchurch地震开始，一直持续到2013年的Seddon和Seddon和Lake Grassmere地震，并在2013年的Grassmere lake Grassmere Eartquakes，以及2016年的Culminik and Culmining in 2016 Kaikikikoura Earthquake。我们注意到，MW 7.1 Darfield地震也是一种复杂的多型破裂。该项目将研究与该区域从俯冲到走滑的复杂构造相关的几个假设。拟议的研究将利用过去二十年在该地区进行的广泛研究的数据和结果，并利用NSF通过快速奖励部分支持的临时余震阵列中的数据。主要的分析工具是地震速度和衰减层析成像，这些速度和衰减层析成像结合了最新和计划的方法论发展，高精度地震搬迁以及局灶性机制分析。这项工作将与GNS Science和惠灵顿维多利亚大学的新西兰科学家密切合作进行，并将与女性的博士后学者一起参与数据分析和解释。该奖项反映了NSF的法定任务，并认为通过基金会的知识分子和更广泛的影响，可以通过评估来审查CRITERIA。

项目成果

Fracturing and pore-fluid distribution in the Marlborough region, New Zealand from body-wave tomography: Implications for regional understanding of the Kaikōura area

体波断层扫描新西兰马尔堡地区的压裂和孔隙流体分布：对凯库拉地区区域了解的启示

• DOI: 10.1016/j.epsl.2022.117666
• 发表时间: 2022
• 期刊: Earth and Planetary Science Letters
• 影响因子: 5.3
• 作者: Heath, Benjamin A.;Eberhart-Phillips, Donna;Lanza, Federica;Thurber, Clifford;Savage, Martha K.;Okada, Tomomi;Matsumoto, Satoshi;Iio, Yoshihisa;Bannister, Stephen
• 通讯作者: Bannister, Stephen

Spatial and temporal stress field changes in the focal area of the 2016 Kaikōura earthquake, New Zealand: A multi-fault process interpretation

2016年新西兰凯库拉地震震源区的时空应力场变化：多断层过程解释

• DOI: 10.1016/j.tecto.2022.229390
• 发表时间: 2022
• 期刊: Tectonophysics
• 影响因子: 2.9
• 作者: Matsuno, Miu;Tagami, Ayaka;Okada, Tomomi;Matsumoto, Satoshi;Kawamura, Yuta;Iio, Yoshihisa;Sato, Tadashi;Nakayama, Takashi;Hirahara, Satoshi;Bannister, Stephen
• 通讯作者: Bannister, Stephen