Tree-Ring Dating of Alpine Fault Earthquakes, New Zealand

小行星9316428 新西兰最近地震的树轮测年是对地震引起的区域落石事件进行地衣测年的一个重要而可靠的检验。 地衣研究表明，自最近一次阿尔卑斯断层地震以来已经过去了大约240年，8.1 + 0.2级地震可能很快会使阿尔卑斯断层断裂约400公里。 地衣测量地震日期的验证将证实建立地震监测和减少地震灾害计划的需要。 同样年龄的小块树木是新西兰西南地区阿尔卑斯断层和海岸之间雨林的典型代表。 由于风暴或地震等干扰事件对森林树冠的部分破坏，新一代的白蜡树（Dacrydium cupressinum）得以发芽并填补空隙。 再生补丁似乎是排水不良（地震敏感）的Okarito森林附近的海岸，我们将使我们的研究土壤较大。 博伊德·科内尔（Boyd Cornere）在一个更内陆的地点对两个地块中的同龄rimu斑块的发芽时间进行了增量核心估计。 他的硕士论文表明，这两块地在大约250年前都发生过树冠开放干扰. 这些初步结果鼓励我们通过研究树木年轮宽度突然增加或减少的时间来准确地确定森林干扰事件的日期。 拟议的树木年代学数据集是Okarito持续生产林选择性采伐的副产品。 我们的工作的初始阶段将是开发一个模型的树木种群年龄的空间格局。 这项重要的任务将使我们能够预测地震震动影响树木年轮宽度的方式。 1993年和1994年将收获大约1 000棵成熟的rimu树。 根据标准的瑞木年表，可以通过树轮宽度和密度的异常模式来识别。 我们将选择，准备，并分析200-300个来自基部rimu树干的切片，以确定树冠开放事件，树木受损事件和发芽日期。 第1年-Okarito森林的林分动态研究;样本收集，运输和准备;测量和交叉定年的树木年轮。 第二年-研究和测定树木年轮异常的年代、分析数据和编写报告。 该项目具有多学科意义。 树木年轮和地衣测年的比较应该验证一种比放射性碳测年更准确的新的表面暴露测年方法。 我们期望确定阿尔卑斯断层相邻的库克和布伦纳段的地震复发间隔，以及最近地震发生的时间。 这将检验大地震即将发生的假设。 生态学的最终产品将是增进对森林动态和微环境以及森林-地貌关系的了解。

9316428 Bull Tree-ring dating of recent New Zealand earthquakes is an important and robust test of lichenometric dating of regional rockfall events caused by earthquakes. Lichen studies indicate that about 240 years have elapsed since the most recent Alpine fault earthquake, and a magnitude 8.1 +0.2 earthquake may soon rupture about 400 km of the Alpine fault. Verification of lichenometry earthquake dates would substantiate needs for establishing seismic monitoring and earthquake hazard reduction programs. Small patches of trees of the same age are typical of the rain forest between the Alpine fault and the seacoast in the South Westland district of New Zealand. Partial destruction of the forest canopy by disturbance events, such as windstorms or earthquakes, allows a new generation of rimu (Dacrydium cupressinum) to germinate and fill the gaps. Regeneration patches appear to be larger on poorly drained (seismically sensitive) soils of the Okarito Forest near the coast where we will make our study. Increment-core estimates of germination times for even-age patches of rimu in two plots at a more inland site were made by Boyd Cornere. His M.Sc. thesis suggests that both plots had a canopy- opening disturbance approximately 250 years ago. These preliminary results encourage us to accurately date forest-disturbance events through study of times of abrupt increase or decrease of tree-ring widths. The proposed dendrochronology data set is a by-product of selective logging in the Okarito sustained-yield forest. An initial phase of our work will be to develop a model for spatial patterns of tree populations ages. This important task will allow us to make predictions about the way seismic shaking will affect tree-ring width. About 1000 mature rimu trees will be harvested in 1993 and 1994. Departures from a standard chronology for rimu will be identified by anomalous patterns of tree-ring widths and densities. We will select, prepare, and analyz e 200-300 sections from basal rimu trunks for dates of canopy-opening events, tree- damage events, and germination dates. Year 1--Stand dynamics study of the Okarito Forest; sample collection, shipping, and preparation; measuring and cross-dating of tree rings. Year 2-- studies and dating of tree-ring anomalies, analysis of data, and report preparation. Our project has multidisciplinary significance. Comparison of tree-ring and lichenometric dates should validate a new surface- exposure dating method that is more accurate than radiocarbon dating. We expect to determine the earthquake recurrence intervals for the adjacent Cook and Brunner segments of the Alpine fault, and the times since the most recent earthquakes. This will test the hypothesis that a major earthquake is imminent. An ecological end product will be improved understanding of forest dynamics and microenvironments, and forest-landforms relations.