EAR-PF: Are large earthquakes like small earthquakes? Using synthetic earthquakes to resolve discrepancies in observations of earthquake stress drop magnitude-invariance

EAR-PF：大地震和小地震一样吗？

• 批准号: 2204102
• 负责人: James Neely
• 金额: $ 18万
• 依托单位: Neely, James Scott
• 依托单位国家: 美国
• 项目类别: Fellowship Award
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2204102&HistoricalAwards=false
• 关键词: EAR; PF; large; earthquakes; like

Dr. James Neely has been awarded an NSF EAR Postdoctoral Fellowship to assess whether small and large earthquakes release energy in the same way. This work will be conducted at the University of Chicago in collaboration with Dr. Sunny Park and Dr. Annemarie Baltay of the U.S. Geological Survey. Larger earthquakes release more energy than smaller earthquakes, but how earthquakes release that energy is not as well understood, despite having important implications for seismologists’ understanding of earthquake processes and, crucially, the seismic hazards that earthquakes pose. Specifically, the way that a given earthquake releases energy determines, at least in part, how strong the shaking will be (which should, in turn, inform building safety standards, etc.). Using computer simulations, Dr. Neely will examine assumptions about how earthquakes release energy and assess whether insights from small earthquakes can help us better understand the hazards posed by rarer, large earthquakes. Additionally, Dr. Neely will work on an initiative to foster knowledge-sharing relationships between Illinois state legislators and researchers within the state.In this project, Dr. Neely will examine the question of whether earthquake stress drop—the decrease in stress along a fault due to an earthquake—is magnitude-invariant. Earthquake stress drop is thought to control the levels of high-frequency shaking that damages buildings, and it may provide insight into earthquake rupture dynamics. Some studies suggest that earthquake stress drop is constant with earthquake magnitude, while others indicate that it varies systematically with magnitude. Because seismologists cannot directly measure stress drop, they cannot compare estimates to the true value, so it is not known which methods are most accurate. Dr. Neely will overcome this issue by generating a large dataset of synthetic earthquakes with known stress drops and then apply four commonly used stress drop estimation methods to this dataset. To simulate real earthquake data, Dr. Neely will generate earthquakes that differ from the simple earthquake models assumed by the stress drop methods and examine how well the stress drop estimates match the true values. Dr. Neely will identity which stress drop method is most accurate and then examine a large dataset of real earthquakes to determine whether stress drop is or is not magnitude-invariant. If stress drop magnitude-invariance is true, seismologists can measure the stress drops of a region’s past small earthquakes to gain insight into the stress drops, and potential shaking levels, of future large earthquakes. But if stress drop magnitude-invariance is false, then seismological models—and as a result policy preparations, including building codes—for this future shaking may be wrong and need major revisions. In addition to this stress drop analysis, Dr. Neely will work to expand the Science One-Pager Initiative (SOPI), an Illinois-based program where graduate students and post-doctoral researchers provide short analyses of scientific topics to state legislators.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.

詹姆斯·尼利（James Nely）博士哈德（Nely Harded）一项nstdoctoral奖学金，以同样的方式评估小地震能量。调查仍然存在，尽管对地震过程的理解具有重要意义，使用计算机模拟的建筑安全RDS等。尼利博士将检查地震释放能量，并评估小地震的见解是否可以帮助我们更好地了解稀有的大地震将努力促进伊利诺伊州立法者与州内的研究人员之间的知识共享关系。在这个项目中，地震压力是否减少了地震压力为了控制损坏建筑物的高频摇动水平，它可能会在某些研究中提供地质ruptore动力学。 ，因此，最准确的压力降低了。方法和检查估计值与压力下降的真实价值相匹配，地震学家可以降低Aregion过去的小地震的压力，从而陷入压力下降，并潜在的摇动水平 - 对于未来的摇晃，可能是错误的，需要大量修订。该奖项反映了NSF'SF'SF'sFly的使命，并通过使用Toundation的知识分子优点和更广泛的影响审查标准来评估值得支持。