Collaborative Research: Can Low-Angle Normal Faults Produce Earthquakes? Reading a Pseudotachylyte 'Rosetta Stone'
合作研究:低角度正断层能否产生地震?
基本信息
- 批准号:1630130
- 负责人:
- 金额:$ 29.04万
- 依托单位:
- 依托单位国家:美国
- 项目类别:Standard Grant
- 财政年份:2016
- 资助国家:美国
- 起止时间:2016-08-01 至 2022-07-31
- 项目状态:已结题
- 来源:
- 关键词:
项目摘要
The physics of earthquake-producing fault rupture has been studied for over a hundred years, a period marked by dramatic advances in the instrumentation and analytical techniques required to understand both the ground shaking (seismicity) caused by fault failure and the physical properties of fault rocks. This research addresses a discrepancy between the long-term rock record of ancient earthquakes and the short-term historical seismic record. Specifically, it focuses on representatives of a class of faults that appear to be poorly oriented for breakage according to the current earthquake mechanics paradigm and Andersonian mechanical theory for the rupture of rocks. According to established theory, normal faults that form at low angles (i.e., less than 30 degrees) should not produce significant earthquakes because the tectonic forces that cause failure are oriented at a high angle to the fault surface. The historical seismicity record generally supports this argument, suggesting that such faults produce only microearthquakes. However, the geologic record contains numerous examples of normal faults that appeared to have slipped at low (less than 30 degree) dips. The presence of pseudotachylite, an extremely quickly cooled, glassy melt rock that generally forms as the result of frictional heating during seismic slip, has been found to be associated with some of these low angle faults, and thus preserves a record of 'fossil earthquakes.' In this study, the principal investigators have identified an unusually rich record of 'fossil earthquakes' on a low angle normal fault in the South Mountains, Arizona. This research is exploring this fossil record with the goal of determining whether or not such faults produce significant earthquakes in non-Andersonian orientations, thus addressing a first-order question in fault mechanics. The research will not only result in a deeper understanding of the earthquake record and the potential seismic hazard of 'misoriented' faults, but also has the potential to transform our understanding of fault mechanics. In addition to the scientific objectives of this research, the project will contribute to the training of graduate and undergraduate students in a STEM (science, technology, engineering, and mathematics) discipline, thus contributing to a more scientifically literate and vibrant society. It represents a collaborative effort between investigators from two research-intensive public universities. Research results will be disseminated by presentation at national geoscience meetings and through the peer-reviewed scientific literature. The results will also be used to engage and educate the public regarding geologic concepts and earthquake hazards through a partnership with the University of Wisconsin Geology Museum to produce participatory exercises and videos and online teaching modules. Low-angle normal faults (LANFs) are poorly oriented for slip according to Andersonian fault mechanics. The geologic record generally supports slip at current low (less than 30 degrees) dips; however, the seismic record generally suggests such faults cannot produce earthquakes greater than magnitude 5.5. One explanation for the discrepancy between these data sets is that the large size and greater efficiency of LANFs result in recurrence intervals longer than the seismic record. A second is that LANFs were re-oriented by isostatic rebound as they were exhumed, allowing them to slip at steeper dips before rotating into their final, shallow orientations. A third explanation, one which reconciles the geologic and geophysical records, is that low angle normal faults fail by creep, producing microseismicity but not substantial earthquakes. Although a convincing explanation for the two active faults that demonstrably record creep, this does not account for the common occurrence of pseudotachylyte in exhumed low-angle normal fault zones worldwide. The purpose of the proposed research is to explore this fossil record of earthquakes using exposures from the South Mountains metamorphic core complex. This site was chosen because pseudotachylyte fault veins are plentiful and amenable to both rock magnetic and geochronologic analyses. This project will test the following hypotheses by integrated structural, thermochronologic, and paleomagnetic analyses and modeling: (1) Recurrence intervals of the largest earthquakes are sufficiently long that they can be distinguished within the error of 40Argon/39Argon isotopic ages (+/- ca. 0.25 million years). (2) Paleomagnetic remanence indicates that earthquakes occurred at current fault dips (less than 30 degrees). (3) Fault veins in the South Mountains record a range of earthquake sizes, the largest of which are greater than magnitude 5.5. The principal investigators will use the magnetic record preserved in pseudotachylyte to quantify fault rotation (tilting), if any, seismogenesis. The remanence vector recorded by each sample will be compared with the expected geomagnetic field direction by correlating the sample?s 40Argon/39Argon age with its concomitant geomagnetic north location and comparison with the North American apparent polar wander path. Any divergence between the two vectors will represent rotation of the system since seismic slip, ultimately allowing us to quantify the angle at which a LANF was active. The cooling history of the wall rock also will be determined using several thermochronometers. Modeling will incorporate these data and constrain earthquake magnitude based on pseudotachylyte fault vein thickness. The project addresses a first-order question in fault mechanics and will provide a deeper understanding of the record of ancient seismicity in the metamorphic core complexes of the western U.S.
对引发地震的断层破裂的物理学研究已有一百多年的历史,这一时期的特点是仪器和分析技术取得了巨大进步,以了解断层破裂引起的地面震动(地震活动)和断层岩石的物理性质。 。这项研究解决了古代地震的长期岩石记录与短期历史地震记录之间的差异。具体来说,它重点关注一类断层的代表,根据当前的地震力学范式和安德森岩石破裂力学理论,这些断层似乎难以破裂。根据既定理论,以低角度(即小于 30 度)形成的正断层不会产生重大地震,因为导致破坏的构造力与断层表面成高角度。历史地震活动记录普遍支持这一论点,表明此类断层仅产生微地震。然而,地质记录包含许多正断层的例子,这些正断层似乎在低倾角(小于 30 度)处滑动。假速石是一种冷却速度极快的玻璃状熔融岩石,通常是由于地震滑动过程中摩擦加热而形成的,已被发现与其中一些低角度断层有关,从而保留了“化石地震”的记录。 '在这项研究中,主要研究人员在亚利桑那州南山区的低角度正断层上发现了异常丰富的“化石地震”记录。这项研究正在探索这一化石记录,目的是确定此类断层是否会产生非安德森方向的重大地震,从而解决断层力学中的一阶问题。这项研究不仅将加深对地震记录和“错误定向”断层潜在地震危险的了解,而且有可能改变我们对断层力学的理解。除了这项研究的科学目标外,该项目还将有助于对研究生和本科生进行 STEM(科学、技术、工程和数学)学科的培训,从而为建设一个更具科学素养和充满活力的社会做出贡献。它代表了两所研究密集型公立大学的研究人员之间的合作努力。研究成果将通过在国家地球科学会议上的演讲和经过同行评审的科学文献来传播。研究结果还将通过与威斯康星大学地质博物馆合作制作参与性练习、视频和在线教学模块,用于吸引和教育公众有关地质概念和地震灾害的知识。根据安德森断层力学,小角度正断层 (LANF) 的滑动方向较差。地质记录通常支持当前低倾角(小于 30 度)的滑移;然而,地震记录通常表明此类断层不会产生 5.5 级以上的地震。对这些数据集之间差异的一种解释是 LANF 的大尺寸和更高的效率导致复发间隔比地震记录更长。第二个是 LANF 在被挖掘出来时通过等静压回弹重新定向,使它们能够在更陡的倾斜处滑动,然后旋转到最终的浅定向。第三种解释是地质学和地球物理记录一致的一种解释,即低角度正断层因蠕变而破坏,产生微震,但不会发生大地震。虽然这对明显记录蠕变的两个活动断层的解释令人信服,但这并不能解释世界范围内挖掘出的低角度正断层带中常见的假速断层。拟议研究的目的是利用南山变质核复合体的暴露来探索地震化石记录。 选择这个地点是因为假速石断层脉丰富且适合岩石磁性和地质年代学分析。该项目将通过综合结构、热年代学和古地磁分析和建模来检验以下假设:(1)最大地震的复发间隔足够长,可以在 40Argon/39Argon 同位素年龄(+/- ca)的误差范围内区分它们。 .25万年)。 (2)古地磁剩磁表明地震发生在现今断层倾角(小于30度)。 (3) 南山断层脉记录了一系列地震震级,最大震级大于5.5级。主要研究人员将使用假速成岩中保存的磁记录来量化断层旋转(倾斜)(如果有的话)和地震发生。通过将样本的 40Argon/39Argon 年龄与其伴随的地磁北位置相关联,并与北美视极漂移路径进行比较,将每个样本记录的剩磁矢量与预期的地磁场方向进行比较。两个矢量之间的任何分歧都将代表系统自地震滑移以来的旋转,最终使我们能够量化 LANF 活动的角度。围岩的冷却历史也将使用多个温度计来确定。建模将结合这些数据并根据假速晶断层脉厚度限制地震震级。该项目解决了断层力学中的一阶问题,并将更深入地了解美国西部变质核复合体的古代地震活动记录。
项目成果
期刊论文数量(0)
专著数量(0)
科研奖励数量(0)
会议论文数量(0)
专利数量(0)
数据更新时间:{{ journalArticles.updateTime }}
{{
item.title }}
{{ item.translation_title }}
- DOI:
{{ item.doi }} - 发表时间:
{{ item.publish_year }} - 期刊:
- 影响因子:{{ item.factor }}
- 作者:
{{ item.authors }} - 通讯作者:
{{ item.author }}
数据更新时间:{{ journalArticles.updateTime }}
{{ item.title }}
- 作者:
{{ item.author }}
数据更新时间:{{ monograph.updateTime }}
{{ item.title }}
- 作者:
{{ item.author }}
数据更新时间:{{ sciAawards.updateTime }}
{{ item.title }}
- 作者:
{{ item.author }}
数据更新时间:{{ conferencePapers.updateTime }}
{{ item.title }}
- 作者:
{{ item.author }}
数据更新时间:{{ patent.updateTime }}
Laurel Goodwin其他文献
Laurel Goodwin的其他文献
{{
item.title }}
{{ item.translation_title }}
- DOI:
{{ item.doi }} - 发表时间:
{{ item.publish_year }} - 期刊:
- 影响因子:{{ item.factor }}
- 作者:
{{ item.authors }} - 通讯作者:
{{ item.author }}
{{ truncateString('Laurel Goodwin', 18)}}的其他基金
From damage zone to core: quantifying mechanical and hydrological coupling during fault-zone structural evolution
从损伤带到核心:量化断层带结构演化过程中的机械和水文耦合
- 批准号:
1951985 - 财政年份:2020
- 资助金额:
$ 29.04万 - 项目类别:
Standard Grant
EAGER: Collaborative Research: Can Low-Angle Normal Faults Produce Earthquakes? A Paleoseismic Perspective
EAGER:合作研究:低角度正断层能否产生地震?
- 批准号:
1237105 - 财政年份:2012
- 资助金额:
$ 29.04万 - 项目类别:
Standard Grant
Student Support for 2010 Electron Backscatter Diffraction Topical Conference
2010 年电子背散射衍射专题会议的学生支持
- 批准号:
1015246 - 财政年份:2010
- 资助金额:
$ 29.04万 - 项目类别:
Standard Grant
Student Support for Electron Backscattered Diffraction Topical Conference
电子背散射衍射专题会议的学生支持
- 批准号:
0813918 - 财政年份:2008
- 资助金额:
$ 29.04万 - 项目类别:
Standard Grant
Collaborative Research: Using Pore Fluid Pressure Gradients to Test the Relative Importance of Hydrologic Versus Mechanical Heterogeneity in Fracture Formation
合作研究:利用孔隙流体压力梯度测试裂缝形成中水文与力学非均质性的相对重要性
- 批准号:
0635965 - 财政年份:2007
- 资助金额:
$ 29.04万 - 项目类别:
Standard Grant
Acquisition of a Versatile Scanning Electron Microscope
购买多功能扫描电子显微镜
- 批准号:
0447332 - 财政年份:2005
- 资助金额:
$ 29.04万 - 项目类别:
Standard Grant
Localization of Deformation in Lithologically Heterogeneous Lower Crust, Arunta Block, Central Australia
澳大利亚中部阿伦塔地块岩性非均质下地壳变形局部化
- 批准号:
0440156 - 财政年份:2005
- 资助金额:
$ 29.04万 - 项目类别:
Continuing Grant
Hydrogeologic Characterization of the Sand Hill Fault Zone, Albuquerque Basin, New Mexico
新墨西哥州阿尔伯克基盆地沙山断裂带的水文地质特征
- 批准号:
9706482 - 财政年份:1998
- 资助金额:
$ 29.04万 - 项目类别:
Continuing Grant
RPG: Characterization of Pseudotachylyte Formed in an Extensional Tectonic Regime
RPG:伸展构造体系中形成的假速石的表征
- 批准号:
9304973 - 财政年份:1993
- 资助金额:
$ 29.04万 - 项目类别:
Standard Grant
相似国自然基金
高功率激光驱动低β磁重联中磁岛对电子加速影响的研究
- 批准号:12305275
- 批准年份:2023
- 资助金额:30 万元
- 项目类别:青年科学基金项目
PUFAs通过SREBPs提高凡纳滨对虾低盐适应能力的机制研究
- 批准号:32303021
- 批准年份:2023
- 资助金额:30 万元
- 项目类别:青年科学基金项目
催化CO2加氢为低碳烯烃的介孔碳限域Fe系催化剂的可控构筑与调控机制研究
- 批准号:22378345
- 批准年份:2023
- 资助金额:50 万元
- 项目类别:面上项目
基于射频指纹物理特征的低轨卫星物联网增强安全认证技术研究
- 批准号:62302082
- 批准年份:2023
- 资助金额:30 万元
- 项目类别:青年科学基金项目
低强度聚焦超声调控前扣带回皮层抑制中枢敏化缓解慢性神经病理性疼痛的机制研究
- 批准号:82360457
- 批准年份:2023
- 资助金额:32 万元
- 项目类别:地区科学基金项目
相似海外基金
Collaborative Research: NSFGEO-NERC: Advancing capabilities to model ultra-low velocity zone properties through full waveform Bayesian inversion and geodynamic modeling
合作研究:NSFGEO-NERC:通过全波形贝叶斯反演和地球动力学建模提高超低速带特性建模能力
- 批准号:
2341238 - 财政年份:2024
- 资助金额:
$ 29.04万 - 项目类别:
Standard Grant
Collaborative Research: NSFGEO-NERC: Advancing capabilities to model ultra-low velocity zone properties through full waveform Bayesian inversion and geodynamic modeling
合作研究:NSFGEO-NERC:通过全波形贝叶斯反演和地球动力学建模提高超低速带特性建模能力
- 批准号:
2341237 - 财政年份:2024
- 资助金额:
$ 29.04万 - 项目类别:
Continuing Grant
Collaborative Research: RUI: Star-Planet Interactions Around Low-mass Stars
合作研究:RUI:低质量恒星周围的恒星-行星相互作用
- 批准号:
2310589 - 财政年份:2023
- 资助金额:
$ 29.04万 - 项目类别:
Standard Grant
Collaborative Research: Development of a Nanofabrication Lab Manual Featuring a Suite of Low-Cost Experiments to Enable Hands-On Training at Community and Technical Colleges
合作研究:开发纳米制造实验室手册,其中包含一套低成本实验,可在社区和技术学院进行实践培训
- 批准号:
2301138 - 财政年份:2023
- 资助金额:
$ 29.04万 - 项目类别:
Standard Grant
Collaborative Research: Development of a Nanofabrication Lab Manual Featuring a Suite of Low-Cost Experiments to Enable Hands-On Training at Community and Technical Colleges
合作研究:开发纳米制造实验室手册,其中包含一套低成本实验,可在社区和技术学院进行实践培训
- 批准号:
2301139 - 财政年份:2023
- 资助金额:
$ 29.04万 - 项目类别:
Standard Grant