Collaborative Research: An Integrated Tectonic Study of the Jamaica Strike-slip Restraining Bend and Gonave Microplate Using GPS, Geomorphologic, Seismic, and Gravity Data

一个由威斯康星大学和德克萨斯大学的科学家组成的研究小组正在对加勒比海的牙买加岛进行一项为期四年的综合地球物理和地质研究。牙买加岛横跨一个主要的走滑断层，该断层抑制弯曲，该弯曲是由于加勒比-北美板块运动在戈纳夫银板块的南北边界之间的分裂而形成的。新的大地测量学、地形学、古地震、重力和地震测量正在结合起来：(1)测量牙买加附近的加勒比板块运动，以建立整个岛屿的断层滑动平衡和相对于加勒比和北美板块的戈纳夫微板块运动；(2)结合地貌学、古地震学和定向重力研究，确定牙买加主要活跃断层的位置、滑动感和长期滑动率；(3)构建和测试断层滑动率的正演和逆演模型，以区分所提出的滑动如何在偏移断层链之间传递的模型，并利用所有测量结果的约束来改进这个人口稠密和地震多发国家的地震危险性评估；(4)将结果与伊斯帕尼奥拉岛的GPS站点速度相结合，得到与所有数据完全一致的Gonave微板运动模型。该项目将有助于更好地了解牙买加的地震灾害，自1600年以来，牙买加经历了两次破坏性地震，由于地震能量集中和该国人口稠密、经济重要的南半部地区松散冲积层的液化，牙买加仍然容易遭受重大地震破坏。这些测量应该提供有关地震周期在空间和时间尺度范围内的有用信息，包括首都金斯顿附近的大芭蕉园断层的千年地震历史和潜力，以及在岛上所有地区积累的震间弹性应变的年复一年预算。这项研究将与牙买加地震台网合作进行，该台网负责地震台网的运作、地震研究以及地震危害评估和反应。

An integrated, four-year geophysical and geological study of the Caribbean island of Jamaica, which straddles a major strike-slip fault restraining bend that has formed in response to partitioning of Caribbean-North America plate motion between the northern and southern boundaries of the Gonave sliver plate, is being carried out by a research team of scientists from the University of Wisconsin and the University of Texas. New geodetic, geomorphologic, paleoseismic, gravity, and seismic measurements are being combined to: (1) measure Caribbean plate motion near Jamaica to establish the full fault slip budget across the island and Gonave microplate motion relative to the Caribbean and North American plates; (2) establish the locations, slip senses, and long-term slip rates along major active Jamaican faults through a combination of geomorphologic, paleoseismologic, and targeted gravity studies; (3) construct and test forward and inverse models of fault slip rates, to distinguish between proposed models for how slip is transferred between the offset fault strands, and to improve earthquake hazard assessment in this densely populated and earthquake-prone country use constraints from all measurements; (4) combine results with GPS site velocities from Hispaniola to derive a model for Gonave microplate motion that is fully consistent with all the data.This project should provide a better understanding of earthquake hazard in Jamaica, which has experienced two destructive earthquakes since 1600 and continues to be vulnerable to significant earthquake damage due to seismic energy focusing and liquefaction of unconsolidated alluvium in much of the heavily populated and economically important southern half of the country. The measurements should provide useful information about the earthquake cycle over range of spatial and temporal scales, including the millenial-scale seismic history and potential of the Plantain Garden fault near the capital city of Kingston to the year-to-year budget of interseismic elastic strain that is accumulating in all areas of the island. The research will be done in collaboration with the Jamaican Seismological Network, which is responsible for seismological network operation, seismic research, and earthquake hazard assessment and response.