Characteristics of Earthquakes Near Plate Interfaces

板块界面附近的地震特征

• 批准号: 8707744
• 负责人: Wang-Ping Chen
• 金额: $ 9.4万
• 依托单位: University of Illinois at Urbana-Champaign
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1987
• 资助国家: 美国
• 起止时间: 1987-08-01 至 1991-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8707744&HistoricalAwards=false
• 关键词: Characteristics; Earthquakes; Near; Plate; Interfaces

This proposal seeks support for a two-year project to investigate the complex but systematic variation of earthquake activities near plate interfaces in Wadati-Benioff zones. In particular, we plan to characterize the nature of a notable number of predominantly normal faulting events that cannot be accounted for by slip on the interplate thrust zone. The depth and mechanism of approximately 100 moderate- sized earthquakes that are shallower than 100 km in major subduction zones will be precisely determined by inverting the long-period P and SH waves at teleseismic distances and by identification of surface reflections from short-period seismograms. We anticipate delineating the position of the plate interface and the seismicity near it in some detail. The results will then be combined with a compilation of source parameters for events in the outer-rise region and intraplate seismicity downdip from the interface. We seek to clarify the possible association of thrust and normal faulting events near the plate interface, the nature of the transition from interplate to intraplate seismicity at intermediate depths, and the connection between intraplate seismicity in the outer-rise region, beneath the plate interface, and beyond the interface in the downdip direction. The ultimate goal of the synthesis is to identify constraints that can be placed upon the state of stress both on the plate interfaceand the subducted lithosphere by the source parameters of earthquakes. We believe that the proposed study would provide enough data to at least qualitatively address several important questions. For instance, if the occurrence and mechanism of events below the plate interface can be correlated with plate tectonic parameters that are believed to control the seismic coupling of the interplate zone, then these events might provide information about the zone both occur, the transition of the strain field within the slab from lithospheric bending seaward of trenches to unbending at intermediate depths will be investigated.

该提案寻求对一个两年期项目的支持， 研究地震的复杂而系统的变化 在Wadati-Benioff带的板块界面附近活动。 在 特别是，我们计划描述一个显着的性质， 主要是正常的断层事件的数量， 是由板间逆冲带的滑动造成的 深度 近100次中等规模地震 在主要俯冲带中， 通过反转长周期P精确确定， SH波在近距离和识别 短周期地震记录的地表反射。 我们 预期描绘板界面的位置， 附近的地震活动 然后将结果与源代码的汇编相结合， 外隆区和板内事件参数 地震活动从界面向下倾斜。 我们试图澄清 逆冲断层和正断层活动的可能联系 板块界面，从板块过渡的性质 中间深度的板间至板内地震活动，以及 外隆板内地震活动与 区域，板界面下方，以及 在下倾方向的界面。 综合的最终目标是确定制约因素 可以放在板上的应力状态下 界面和俯冲岩石圈的震源参数 地震。 我们认为，拟议的研究将 提供足够的数据，至少定性地解决几个 重要的问题 例如，如果事件和 板块界面以下的事件机制可以相互关联 板块构造参数控制着 板间带的地震耦合，那么这些事件 可能会提供有关区域的信息， 应变场在板内从 岩石圈从海沟向海弯曲到不弯曲. 将研究中间深度。