Geomorphic Research For The Catchment Within Yishu Active Tectonic Zone Based On DEM

In recent years, quantitative analysis of the regional tectonic activity using the geomorphic parameters extracted by DEM has received considerable attention in the field of neotectonics. The survey region is confined to longitude 117°7?¹19°42?E and latitude 34°20?³7°8?N located in the central of shandong province. And it belongs to denudation landform of hilly and mountainous area in the central south of Shandong. The terrain is high in west and low in east and the highest altitude is 1126 meters. Yishu Fault Zone consists of four major faults which are Changyi-Dadian fault?F₁?, Anqiu-Juxian fault?Baifenzi-Rulaishan fault??F₂?, Yishui-Tangtou fault?F₃? and Tangwu-Gegou fault?F₄?. These faults belong to shandong section of Tanlu Fault Zone from east to west. In this work, four unicity geomorphic parameters including hypsometric integral?Hi?, stream-gradient index?SL?, drainage basin asymmetry?AF?,drainage basin shape?Bs? and one comprehensive index of relative active tectonics?Iat?for four river drainage basins of Bailang River, Weihe River, Yihe River and Shuhe River across the Yishu Fault Zone, have been extracted by the GIS technique based on SRTM DEM date as data source. These basins contain 98 sub-basins which are composed of 10, 27, 26 and 35 sub-basins for Bailang River, Weihe River, Yihe River and Shuhe River, respectively. The calculated results for Hi value illustrat that the values range from 0.09?B3-1? to 0.35?S1-15?. The hypsometric curves appear as a concave shape. Hi values are divided into 3 parts?Hi?0.26,0.15?Hi<0.26 and Hi<0.15? according to the feature of hypsometric curves by 0.1 Value Gap. SL, AF, Bs,and Iat values range from 18.12?B2-2? to 4511.96?Y1-7?, 12.11?W2-1? to 91.39?S2-3?,0.06?W1-13? to 12.11?Y4-2?, and 1.5 to 3.0, respectively. Results show that all Hi values of the sub-basins are less than 0.35, indicating that the evolutionary phase of the drainage basin is in the old age. In addition, the geomorphic parameters of four main fault zones of the Yishu fault zone exhibit significant differences in space. Compared to other faults, the north of F₁ fault and the south of F₄ fault have higher Bs values. The SL and AF values of the South of F₂ fault are higher than those of other faults, while the midsection of F₃ fault and the north of F₄ fault have higher Hi, SL and AF values.Based on the Iat classification criterion established by Hamdouni, F₁ fault between Dadian and Zuoshan, the south of F₂ fault between Huaqiao and Yaoshang, the north ofF₃ fault between Tangwu and Mazhan and the midsection of the F₄ fault are classified into high intensities.