In the present study, we assess seismic hazard potential and surface deformation pattern along and across the strike of major active faults in the intra-plate Kachchh Rift Basin (KRB). Towards this, we adopted river Gradient Length Anomaly (GLA) technique, which detects recent tectonic deformation along a river profile on local and regional scales. The major deviations along the river profile can be correlated with exogenic (erosion/sedimentation/anthropogenic) and endogenic (active tectonic movement) processes. We analysed 130 river profiles for GL anomalies, over an area of ~26,700 km² in the KRB to identify possible locations that have undergone active tectonic deformation associated with the fault movement. The acquired results show that the higher magnitude negative GL anomalies (uplift) are observed proximal to the fault zones. Our estimates reveal that, around 13% of the study area falls under high tectonically active zone, around 27% of the area falls under moderately active zone, while 60% of the area shows very low or negligible tectonic activity. The estimated results of the GL anomalies are compared with the existing double-difference tomograms, to understand the role of subsurface fault dynamics on the GL anomalies. Furthermore, the results of GLA are correlated with the existing results of the peak ground acceleration (PGA) values of the basin, in order to obtain the precise information regarding surface deformation and site-specific ground acceleration for accurate assessment of seismic hazard.

中文翻译：

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使用河流坡度长度异常技术评估印度西部卡奇地区的地震灾害

在本研究中，我们评估了沿板块内卡赫奇裂谷盆地（KRB）内主要活动断层走向的地震危险势和地表变形模式。为此，我们采用了河流梯度长度异常（GLA）技术，该技术可检测沿局部和区域尺度的河流剖面的最新构造变形。沿河剖面的主要偏差可能与外生（侵蚀/沉积/人为）和内生（活跃的构造运动）过程有关。我们分析了〜26,700 km ²区域中130个河流剖面的GL异常。在KRB中识别出与断层运动有关的活动构造变形的可能位置。所获得的结果表明，在断层带附近发现了更大的负GL异常（隆升）。我们的估计表明，大约13％的研究区域属于高构造活动带，大约27％的区域属于中等活动带，而60％的区域显示出非常低的或可忽略的构造活动。将GL异常的估计结果与现有的双差断层图进行比较，以了解地下断层动力学对GL异常的作用。此外，GLA的结果与流域地面加速度（PGA）峰值的现有结果相关，