Abstract To elucidate how landscapes respond to either tectonic and climatic changes through time, geomorphologists use the analysis of river and basin morphometry. Many studies have evaluated how rivers, and consequently hillslopes, respond to changes in the rate of rock uplift in compressional settings. The case of extensional settings, however, has received less attention. We examine the case of landscape response to tectonics in west-central Mexico to identify zones where there is notable increase in the tectonic activity. The study of west-central Mexico is challenging for the morphometric analysis since there is an interplay between the development of extensional structures and pulses of volcanism, mainly from Eocene to Oligocene and Pliocene to Pleistocene, that have buried large parts of the landscape. For our purpose we use the normalized channel steepness index (ksn) to evaluate how this index correlates with other morphometric parameters such as the hillslope gradient, hillslope convexity and concavity, terrain rugosity and first order stream gradient (Fosg). We use the landform units map as the spatial unit of analysis and from this, we estimate the morphometric properties of the landscape. The results of the morphometric analysis indicate that the topography of Eocene to Oligocene volcanic landscapes are well explained (~70%) by the ksn and in less degree for Pliocene to Pleistocene landscape where ksn accounts for ~55–66% of landscape morphometry. Our results also indicate that the ksn is the best suited among all morphometric variables used in this study and confirm that the landscape of west-central Mexico is dominated by river incision. Landscape incision is particularly high on the northern part of the Jalisco block, mainly along the Ameca river and its tributaries such as Atenguillo river, and north of the Jalisco block, along the Santiago river and on tributaries incising the Sierra Madre Occidental. Finally, the morphometric analysis indicates that even for the case where the volcanic rocks and sediments are filling up large parts of the landscape, river incision resulting from the tectonic activity is capable to cut into lavas, propagating the change imposed by the tectonic activity.

中文翻译：

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使用地形分析评估哈利斯科地块和邻近地区（墨西哥中西部）的景观对构造的响应

摘要 为了阐明景观如何随着时间的推移对构造和气候变化做出反应，地貌学家使用了河流和盆地形态测量学的分析。许多研究评估了河流以及山坡如何响应压缩环境中岩石隆起速率的变化。然而，外延设置的情况较少受到关注。我们研究了墨西哥中西部构造的景观响应案例，以确定构造活动显着增加的区域。墨西哥中西部的研究对形态测量分析具有挑战性，因为伸展结构的发展与火山活动的脉动之间存在相互作用，主要是从始新世到渐新世和上新世到更新世，它们已经掩埋了大部分景观。出于我们的目的，我们使用归一化的通道陡度指数 (ksn) 来评估该指数如何与其他形态测量参数相关，例如山坡坡度、山坡凸度和凹度、地形起伏度和一阶流坡度 (Fosg)。我们使用地形单位地图作为分析的空间单位，并由此估计景观的形态特征。形态测量分析的结果表明始新世至渐新世火山景观的地形由 ksn 很好地解释（~70%），而上新世至更新世景观的程度较低，其中 ksn 占景观形态测量的~55-66%。我们的结果还表明 ksn 是本研究中使用的所有形态测量变量中最适合的，并证实墨西哥中西部的景观以河流切口为主。哈利斯科地块北部的景观切口特别高，主要沿阿梅卡河及其支流，如阿滕吉略河，哈利斯科地块北部，圣地亚哥河沿线和西马德雷山脉的支流。最后，形态测量分析表明，即使在火山岩和沉积物填满大部分景观的情况下，构造活动造成的河流切口也能够切割成熔岩，传播构造活动带来的变化。