Stratigraphic Evidence for Late Quaternary Temporal Clustering of Large Earthquakes on the Puente Hills Segment of the Elysian Park Thrust, Eastern Los Angeles.....

Puente Hills位于洛杉矶盆地东部，是圣莫尼卡山脉-伊利斯公园背斜的地表表现，该背斜正在形成对盲推力坡道运动的响应。这项研究将解决整个断层同时破裂的可能性，在一次非常大的地震事件中，或在几个较小的北岭地震事件中，或在许多惠特尔-纳尔斯地震事件中。通过对三条蜿蜒河流的第四纪沉积物的分析，这些河流穿过该构造，包含粗砂和富有机质层的交替，将有可能确定和比较普恩特山冲断斜坡上过去变形事件的时间。这项研究将包括在两种不同的尺度上进行分析，使用石油和水的测井资料以及河流和海洋阶地沉积物，并对专门为该项目挖掘的钻孔进行高精度放射性碳定年和测井。该结果将提供与圣莫尼卡山脉-伊利斯公园背斜有关的过去地震的时间和震级的限制。

9416321 Wells The Puente Hills, in the eastern Los Angeles Basin, are the surface expression of the Santa Monica Mountains - Elysian Park anticlinorium which is forming the response to movement on blind thrust ramps. This study will address the likelihood of the entire fault rupturing simultaneously, in one very large earthquake event, or in several smaller events of Northridge- type, or in numerous small events of Whittier-Narrows-type. By analysis of Quaternary sediments in three meandering rivers that cross the structure and that contain alternating coarse sand and organic-rich beds, it will be possible to determine and compare the timing of past deformation events on the Puente Hills thrust ramp. The research will involve analyses at two distinct scales using oil and water well logs and fluvial and marine terrace deposits, and high- precision radiocarbon dating and logging of boreholes excavated specifically for this project. The results will provide constraints on the timing and magnitude of past earthquakes connected with the Santa Monica Mountains - Elysian Park anticlinorium.