Index of Active Tectonic Assessment: Quantitative-based Geomorphometric and Morphotectonic Analysis at Way Belu Drainage Basin, Lampung Province, Indonesia

Abstract

The occurrence of subduction zones caused by the collision between the Eurasian-Western Indonesia Plate due to an increase tectonic, volcanic and magmatic activities along Sumatra Island. This study covers the area of Way Belu Drainage Basin, located near Bandar Lampung City, Lampung Province, southern part of Sumatra, Indonesia. The area composes of a complex geological structure as the result of tectonic activities. In this study, geomorphic indices assessment such as morphometric and morphotectonic quantitative analysis are undertaken to identify the Index of Active Tectonics (IAT). The morphometric analysis uses Drainage density (D d) and Ratio of bifurcation (R b). The value of D d respectively from 1.45 to 4.05, R b from 2 to 10. While the morphotectonic analysis uses basin shape index (Bs), valley floor width-valley height ratio (V f), and asymmetry factor (AF). The value of Bs from 1.27 to 6.25, V f from 0.16 to 3.30, and AF from 22.73 to 83.77 in ranges which is derived average IAT value is 2.20. It may considered that at the Way Belu Drainage Basin has moderate to high tectonic activity. From the joint measurement results on the fracture zone express that the main pattern of faults has trend NWW-SSE, NE-SW, NNE-SSW, NW-SE, and WE directions. Furthermore, based on the combination of the quantitative geomorphology indices assessment which is supported by remote sensing and field assessment shows that those features closely related to the Semangko Fault System with the NNW-SSE fault trend parallel to its fault.

Sub Surface Active Fault Identification on Quaternary and Tertiary Rocks using Geoelectric Method in Cilaki Drainage Basin, Southern Part of West Java, Indonesia

“…The calibration of tool and equipment is necessary to minimize of the resistivity value error. The differences of resistivity value between Quaternary volcanic rock and Tertiary sedimentary rock can be used to find quantitatively of the lithological boundaries, fault and deformation areas [11]- [13], [18], [20], [23], [24]. The result of resistivity value measurement on GL 1 to GL 5 is find the resistivity values of rock between 80 and 450 Ω meters with variation of depth between 0 and 110 meters (Fig.…”

“…Where: Lmf is the length along the mountai-piedmont junction; Ls is the overall length of the mountain front [6] [8] [9]. The Smf index is suitable for the tectonic activity [18]. In this study, result of geoelectric method used to emphasize of active fault existance.…”

Seismotectonic analysis of the Viraayots–Karabakh zone (Armenia) and the adjacent areas of Lesser Caucasus

“…С этой целью были применены следующие тектоно-геоморфологические индексы: индекс соотношения ширины и глубины долины (Valley floor width-valley height Ratio, VF), индекс относительной расширенности склонов (Relative Slope Extension Index, RDEt), показатель густоты линеаментной сети (Lineament Density, LD), гипсометрический интеграл (Hypsometry Integral, HI), индекс относительной кривизны подножья склона (Mountain Front Sinuosity, Smf), а также индекс тектонической активности (Index of Active Tectonics, IAT), который суммирует все вышеперечисленные показатели. Подсчет всех показателей был произведен по методике, представленной в работах [Mahmood, Gloaguen, 2012;Etchebehere et al, 2006;Moussi et al, 2018;Singh et al, 2008;Gentana et al, 2018]. Результаты оценки неотектонической активности для некоторых блоков взяты из ранее проведенной работы .…”

General regularities of seismic activity of Northern Armenia in connection with block structure and tectonic activity

“…Для оценки тектонической активности блоков ис следуемой территории были применены следующие тектоногеоморфологические показатели: индекс со отношения ширины и глубины долины (Valley floor width -valley height Ratio, V F ), индекс относительной расширенности склонов (Relative Slope Extension Index, RDEt), показатель густоты линеаментной сети (Linea ment Density, L D ), гипсометрический интеграл (Hypso metry Integral, HI), индекс относительной кривизны подножья склона (Mountain Front Sinuosity, S mf ), а также индекс тектонической активности (Index of Active Tec tonics, IAT), который суммирует все вышеперечислен ные показатели. Подсчет всех показателей был произ веден для каждой блоковой единицы по соответствую щей методике [Mahmood, Gloaguen, 2012;Etchebehere et al, 2006;Moussi et al, 2018;Singh et al, 2008;Gentana et al, 2018]. Несколько слов о каждом из примененных геоморфологических индексов.…”