Thermal-Mechanical Behavior of Oceanic Transform Faults

大洋转换断层的热力学行为

• 批准号: 0623188
• 负责人: Mark Behn
• 金额: $ 15.03万
• 依托单位: Woods Hole Oceanographic Institution
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-01 至 2009-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0623188&HistoricalAwards=false
• 关键词: Thermal; Mechanical; Behavior; Oceanic; Transform

The researchers will conduct a study to investigate the thermo-mechanical behavior of oceanic transform faults to address the discrepancies between the geologic observations and the predictions from numerical models. Previous studies that incorporated 3-D conductive and advective heat transport surrounding transform faults used simplified rheologic and heat transport relationships to simulate the behavior of the lithosphere and underlying asthenosphere. For example, most of these studies ignored important effects, such as brittle weakening of the lithosphere, non-linear rheology, shear-heating, hydrothermal circulation, and serpentinization. Moreover, although the half-space cooling model does the best job explaining the depth of transform fault seismicity, it neglects all physics associated with mantle flow. The goal of the proposed study is to create more self-consistent models for the behavior of oceanic transform faults that incorporate: 1) Hydrothermal circulation and shear-heating (viscous dissipation) 2) Brittle deformation processes and metamorphism 3) Non-linear and grain-size dependent rheology Initial results simulating brittle weakening suggest that a more realistic treatment of rheology, based on laboratory data, may explain many of the seemingly discrepant observations at oceanic transform faults. Broader impacts include support for a young scientist and a graduate student.

研究人员将进行一项研究，调查海洋转换断层的热机械行为，以解决地质观测与数值模型预测之间的差异。以前的研究，包括3-D的传导和对流热输运转换断层周围使用简化的流变学和热输运的关系来模拟岩石圈和下面的软流圈的行为。例如，这些研究大多忽略了重要的影响，如岩石圈的脆性弱化，非线性流变学，剪切加热，热液循环和蛇纹岩化。此外，尽管半空间冷却模型在解释转换断层地震活动的深度方面做得最好，但它忽略了与地幔流相关的所有物理学。拟议研究的目标是为海洋转换断层的行为创建更多的自洽模型，其中包括：1）水热循环和剪切加热（粘性耗散）2）脆性变形过程和变质作用3）非线性和粒度相关流变学模拟脆性弱化的初步结果表明，基于实验室数据，可以解释海洋转换断层上许多看似不一致的观测结果。 更广泛的影响包括对一名青年科学家和一名研究生的支持。