The Long Term Slip Rate and Recurrence Interval of the Hukou Fault

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The Long Term Slip Rate and Recurrence Interval of the Hsinchu Fault

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 The long term slip rate and recurrence interval of the Dajianshan Fault

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The Long Term Slip Rate and Recurrence Interval of the Hengchun Fault

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The long term slip rate and recurrence interval of the Meishan Fault

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The Long Term Slip Rate and Recurrence Interval of the Hsinchu Fault

        The exposed fault trace of the Hsinchu Fault is located northeastwards along the terrace scarp of the Dajuanli Coast to the Touchianshi Riverbed. The fault trace is unapparent due to the coverage of the Holocene alluvium. The previous research indicates that the Hsinchu Fault merged into the Shincheng Fault when it stretched eastward. The surface length of Hsinchu Fault is approximately merely 16 kilometers in the onland. In respect of the both sides of the fault, tens of meters of alluvium on the footwall are unconformably accumulated on the Toukoshan Formation (Yangmei Formation) since the late Pleistocene. The hanging wall is also the Toukoshan Formation (Shiangshan sandstone), but the lateritic terrace gravel layer of the late Pleistocene is covered on the Toukoshan Formation in angular unconformity. According to the reverse fault system, the Hsinchu Fault formed an anticline on the fault tip, which is a fault-bend fold. The vertical shift of the two sides of the fault is insignificant; it mainly appears to be folding deformation.

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       This research conducts 8 core-boring in the coastal area of west Hsinchu. The core-boring method is utilized to estimate deformation rate. Analyzed from the 8 boreholes and the 14C date, the elevation difference of the Toukoshan Formation between the Hsinchu Borehole 2 and Hsinchu Borehole 8 is 19 meters. The thickness change of the late Pleistocene fluvial gravel deposits shows that the Hsinchu Fault goes through between the two boreholes. Besides, the calculated vertical deformation rate slightly differs, the footwall shows a subsided rate of -0.10.4 mm/yr; the hanging wall shows an uplift rate approximately 1mm/yr. The relative vertical uplift rate on both sides of the fault is ~1 mm/yr.

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The profile of the Hsiangshan Coast borehole of the Hsinchu Fault, the height to length ratio is 1:10.

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The average vertical deformation rate of the boreholes on the two sides of the Hsinchu Fault.

 

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