Stream Responses to Uplift, Northern Canterbury, New Zealand

希望断层附近的新西兰河流对晚第四纪隆升和气候变化反应迅速，因此是发展新概念的理想选择。这些强大的溪流在大约3万年前和现在的基岩上切割出宽阔的河道。确认3万年的年龄估计，并测量自那时以来的河道下降量，将(1)识别活动断层和褶皱，(2)为晚第四纪隆升速率的区域图提供数据。这张地图将用于区分局部隆起和区域隆起，并描述由于太平洋板块和澳大利亚板块的斜辐合而形成的具有不同构造风格的子区域。溪流梯度指数描述了河道坡度的变化，并将用于进一步检查近期断层的数量，并研究由不同功率的溪流断层引起的急流和瀑布的上游迁移率。阶地踏面和沟槽表面也将作为时间线通过快速变形的景观进行评估。溪流阶地在美国西部的山谷中很常见，但不像更丰富和广泛的新西兰阶地那样适合于有效和完整的构造模式测试。本研究的概念和方法将适用于许多其他具有不同气候、岩石可蚀性、阶地年龄和水流动力的构造活跃地区。在新西兰进行了彻底的测试后，建议的模型应该作为一种新的方法来更好地定义美国西部的高地震风险区域。

New Zealand streams near the Hope fault have responded rapidly to late Quaternary uplift and climatic changes, and thus are ideal for the development of new concepts. These powerful streams cut broad straths in bedrock at about 30,000 years ago, and at the present. Confirmation of the 30,000 years age estimate, and measuring amounts of stream-channel downcutting since then, will (1) identify active faults and folds and (2) provide the data for a regional map of late Quaternary uplift rates. This map will be used to separate local from regional uplift and to describe subareas with different tectonic styles that have results from the oblique convergence of the Pacific and Australian plates. Stream-gradient indices describe variations in channel slope and will be used to further examine amounts of recent faulting and to study rates of upstream migration of rapids and waterfalls caused by faulting in streams in with different amounts of power. Terrace tread and strath surfaces will also be evaluated as time lines passing through rapidly deforming landscapes. Stream terraces are common in the valleys of the western United States, but are not as suitable for efficient and complete testing of the tectonic model as the more abundant and extensive New Zealand terraces. Concepts and methods resulting from this study will be applicable to many other tectonically active regions, with different climates, rock erodibility, terrace ages, and streams power. After thorough testing in New Zealand, the proposed model should be used as a new approach to better define areas of high seismic risk in the western United States.