RESPONSES OF THE S-A DOUBLE-LOG GRAPH,CONCAVITY INDEX AND STEEPNESS INDEX OF CHANNELS TO THE TECTO-NIC MOVEMENT OF THE HUOSHAN PIEDMONT FAULT |
| |
| Authors: | BI Li-si HE Hong-lin XU Yue-ren WEI Zhan-yu SHI Feng SUN Hao-yue |
| |
| Affiliation: | 1.Key Laboratory of Active Tectonics and Volcano, Institute of Geology, China Earthquake Administration, Beijing 100029;2.Key Laboratory of Earthquake Monitoring and Disaster Mitigation Technology, Guangdong Earthquake Administration, Guangzhou 510070;3.Institute of Earthquake Science, China Earthquake Administration, Beijing 100036 |
| |
| Abstract: | The Huoshan piedmont fault is a small watershed region in Shanxi Province. We utilized the high-resolution DEM data and the stream-power incision model which describes the relationship between the tectonic uplift and fluvial incision to analyze the S-A double-log graph, concavity index (θ)and steepness index (logks) of the 64 channels across this fault and discuss their responses to the tectonic movement of the fault. The results show that (1)the S-A double-log graphs all exhibit an obvious convex form, which is the direct expression of the response to the situation that the bedrock uplift rate is higher than the fluvial incision rate. (2)All of the concavity index (θ)values of 64 channels are lower than 0.35 with an average value of 0.223, much lower than the empirical value (0.49)of the rivers in steady state. These low values are the quantitative reflections of the channels' slightly concave profiles. Meanwhile they imply that these channels across the fault are very young. There is no enough time for them to adjust the profiles through the fluvial incision to the steady state because of the fault's frequent and strong tectonic movements. (3)The steepness index values of the channels located in the Laoyeding Mt. are highest, while they are lower in the northern and southern mountains. Moreover, the steepness index values of the channels in the northern mountains, on average, are higher than those of the channels in the southern mountains. To a certain extent, this distribution of the steepness index corresponds to the difference in the uplift rates of the Huoshan piedmont fault. It means that the uplift rate of the middle fault segment in the Laoyeding Mt. is highest, and the uplift rate of the northern segment is higher than that of the southern segment. |
| |
| Keywords: | Huoshan piedmont fault stream-power incision model channels DEM S-A double-log graph concavity index steepness index response to tectonic movement |
|
|
