The structural evolution of active fault and fold systems in central Otago, New Zealand: evidence revealed by drainage patterns
The structural evolution of active fault and fold systems in central Otago, New Zealand: evidence revealed by drainage patterns
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DOI：
10.1016/s0191-8141(96)80046-0
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发表时间：
1996-02
影响因子：
3.1
通讯作者：
J. Jackson;R. Norris;J. Youngson
中科院分区：
文献类型：
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作者：
J. Jackson;R. Norris;J. Youngson
新西兰的奥塔哥中部是一个大陆缩短活跃的地区，在这个地区，一个被切割成片岩的平原表面被褶皱所变形，这些褶皱是在埋藏的逆断层之上发育的。我们使用该地区的排水模式来展示褶皱（和断层）生长和相互作用的各种过程，这些过程很难通过其他手段来识别。特别是，我们显示：（1）简单的不对称褶皱如何发展成箱状褶皱;（2）表面上连续的山脊是如何由分离的褶皱（和断层）段合并而成的;（3）相邻构造的相对年龄（或相对抬升速率）的证据;（4）褶皱（或断层）生长时的传播方向的证据。我们获得的几个定量估计的故障传播速率表明，在长度约20公里的断层上，每次地震的长度增加10-50米。这些估计是非常不确定的，但在规模上与内华达州对类似大小的正断层的估计相似，也与理论增长模型的预测估计相似。他们提出了一个问题，即断层生长，地震复发率和气候变化是否可以相互作用，在一个活跃的景观中产生半规则的离散特征。
Central Otago in New Zealand is an area of active continental shortening in which a peneplain surface cut into schist has been deformed by folds, which are developed above buried reverse faults. We use the drainage patterns in this region to demonstrate various processes in fold (and fault) growth and interaction that would be difficult to identify by other means. In particular we show: (1) how simple asymmetric folds can develop into box folds; (2) how apparently continuous ridges were formed by the coalescing of quite separate propagating fold (and fault) segments; (3) evidence for the relative ages (or relative uplift rates) of adjacent structures; and (4) evidence for the propagation direction of folds (or faults) as they grow. The few quantitative estimates we obtain for fault propagation rates suggest an increase in length of 10–50 m per earthquake on faults about 20 km long. These estimates are very uncertain, but are similar in magnitude to an estimate made in Nevada for a normal fault of similar size and are also similar to predicted estimates from theoretical growth models. They raise the question of whether fault growth, earthquake recurrence rates and climate change can interact to produce semi-regular discrete features in an active landscape.