Abstract The Saurashtra peninsula, a Deccan Trap terrain, in western India lacks the studies that document on-land information of tectonically active faults. In the present paper, the tectonogeomorphology of the Shetrunji River basin is investigated to identify the neotectonic signatures of the buried structural element by detailed analyses of the landforms and drainage pattern using quantitative geomorphic analysis, morphostructural studies and Gradient length analysis (GLA) along with field investigation. The basin has been divided into three segments based on channel orientation, (a) Segment-1 (upper reach): oriented in NE-SW direction (b) Segment-2 (middle reach): oriented in an E-W direction and (c) Segment-3 (lower reach): oriented in NW-SE direction. The tectono-geomorphic analysis suggests the neotectonic deformation is mainly demonstrated by the NE-SW oriented Girnar Fault (GF) in Segment-1 and E-W oriented Shetrunji Fault (SF) in Segment-2. The Segment-3 interestingly shows least or no tectonic deformation signatures. For the first time, we report the geomorphic evidence of the two main faults 1) the Girnar Fault (GF) ~ a left-lateral strike slip fault and 2) the Shetrunji Fault zone (SFz) ~ a right-lateral strike slip fault. The interplay between drainage pattern and buried structures are observed in the form of offset channel/offset ridges, deflection in stream and linear valleys. The SFz is characterized by an anastomosing drainage pattern, offsetting/deflection of streams and development of linear valleys in zone which is 52 km in length and 2 km wide. The SL index and Ksn show high values along the fault zone, which is also, supported by the presence of incised river channel, entrenched mender and incised ravine surfaces. The study reveals the prevalent neotectonic activity in the Shetrunji River basin along with the GF and the SFz. The findings are consistent with the geomorphic - structural setup of the region, and coincide with the historical as well as current seismicity distribution.

中文翻译：

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印度西部谢特鲁吉河德干火山省新构造不稳定性的地貌响应：定量地貌学的见解

摘要 印度西部的德干圈闭地形索拉什特拉半岛缺乏记录构造活动断层陆上信息的研究。在本文中，通过使用定量地貌分析、地貌结构研究和梯度长度分析 (GLA) 以及实地分析对地貌和排水模式进行详细分析，研究了谢特伦吉河流域的构造地貌，以确定埋藏结构元素的新构造特征。调查。盆地已根据河道方向分为三个部分，（a）Segment-1（上游）：面向 NE-SW 方向（b）Segment-2（中游）：面向 EW 方向和 (c) Segment-3（下游）：面向 NW-SE 方向。构造地貌分析表明，新构造变形主要表现为第 1 段的 NE-SW 向的 Girnar 断层（GF）和第 2 段的 EW 向的 Shetrunji 断层（SF）。有趣的是，Segment-3 显示出最少或没有构造变形特征。我们首次报告了两个主要断层的地貌证据：1）Girnar 断层（GF）~左侧走滑断层和 2）Shetrunji 断裂带（SFz）~右侧走滑断层。排水模式和掩埋结构之间的相互作用以偏移通道/偏移脊、河流和线性山谷的偏转的形式观察到。SFz的特点是具有吻合的排水模式，河流的偏移/偏转和长52公里，宽2公里的区域内线性山谷的发展。SL 指数和 Ksn 沿着断层带显示出高值，这也得到了存在下切河道、根深蒂固的修补物和下切沟壑表面的支持。该研究揭示了 Shetrunji 河流域以及 GF 和 SFz 普遍存在的新构造活动。研究结果与该地区的地貌-结构设置一致，并与历史和当前的地震活动分布一致。