EAPSI: The Effect of Asperities on Geological Properties and Forearc Topography at Subduction Region

该奖项支持研究撞击测深特征对在所罗门和新赫布里底俯冲带等地观察到的地震周期与长期隆起和沉降周期之间关系的影响。 本课题是以数值试验为基础的。一个强大的，自适应的，多维的，有限元法求解器，Dynearthsol 2D/3D，将用于完成该项目，以适应大空间（高达400公里）和时间（高达105年）的规模。该项目将在台湾的Academic Sinica进行，由Dynearthsol 2D/3D的主要贡献者之一Tan Eh博士指导。 初步结果不仅有助于改善科学界对构造观测的解释。它们还将帮助官员进行长期的地震/海啸预测，以及在苏门答腊、所罗门和具有类似地质背景的地区防备和减轻随后的灾害，人们对弹性应变积累、释放的地震周期与会聚边缘的长期构造变形之间的关系仍然知之甚少。非弹性应变的长期积累导致俯冲带的地形变化被认为是在多个地震周期中发生的。然而，虽然机制释放滑动同震孕震区是很好的理解，应变积累的方式，在俯冲带的弧前地区造成长期变形，仍然是一个有争议的问题。此外，当随着时间的推移进行整合时，同震隆起与所罗门和新赫布里底群岛前弧区等地的长期垂直变形不匹配，这些地区的大型测深特征在海沟处被俯冲。基于这一点和类似的观察，可以推断，同震滑动不是唯一的机制，主导长期变形过程中的前弧。本计画将以数值方式探讨同震滑动与长期变形如何累积，并在俯冲带中与俯冲界面处的大凹凸体相互作用。这个NSF EAPSI奖支持美国研究生的研究，并与台湾科技部合作资助。

This award supports research to study the effects of impinging bathymetric features on the relationship between seismic cycle and long-term uplift and subsidence cycles observed in places such as the Solomon and New Hebrides subduction zones. This project is based on numerical experiment. A robust, adaptive, multi-dimensional, finite element method solver, Dynearthsol2D/3D, will be used to accomplish the project in order to accommodate large spatial (up to 400 km) and time (up to 105 years) scales. This project will take place at Academic Sinica, Taiwan, under the mentorship of Dr. Tan Eh, one of the major contributor to Dynearthsol2D/3D. The preliminary results will not only help to improve explanations of tectonic observations within the scientific community. They will also help officials with long-term earthquake/tsunami prediction as well as preparation and mitigation of subsequent hazards in Sumatra, Solomon, and regions with similar geological settings.The relationship between the earthquake cycle of elastic strain accumulation, release and longer-term tectonic deformation at convergent margins is still poorly understood. Long-term accumulation of inelastic strain that results in topographic changes at subduction zones is believed to occur over multiple earthquake cycles. However, while the mechanism releasing slip co-seismically on the seismogenic zone is well understood, the way strain accumulates interseismically, causing long-term deformation in the forearc region of subduction zones, is still a matter of debate. Moreover, when integrated over time, coseismic uplift poorly matches the longer-term vertical deformation in places such as the Solomon and New Hebrides forearc regions where large bathymetric features are being subducted at the trench. Based on this and similar observations, it is inferred that coseismic slip is not the only mechanism dominating the long-term deformation processes at forearcs. This project will investigate numerically how coseismic slip and long-term deformation accumulate and interact at subduction zones with the presence of large asperities at the subduction interface. This NSF EAPSI award supports the research of a U.S. graduate student and is funded in collaboration with the Ministry of Science and Technology of Taiwan.