Landform is the shape of the earth's surface, which is the combined influence of tectonic movement and surface erosion. Geomorphic indexes are the quantitative methods applied in geomorphology, aiming to extract the tectonic and erosion information from the surface morphology. Since the 1950s, the HI(Hypsometric Integral)had been used to quantitatively characterize the three-dimensional volume residual rate of drainage basins after erosion and to estimate the geomorphic evolution stage, and the relief had been used to evaluate the erosion response of regional tectonic uplift. Since the 1970s, with the construction of the stream power incision model, the k_sn(Steepness)based on the model has been widely used to estimate the distribution of uplift rate, and it has become an important branch of geomorphology to obtain the information contained in the landform by using geomorphic indexes. The quality of terrain data affects the research level of geomorphology. In the early stage of geomorphic research, field survey is the main method to carry out quantitative statistics of geomorphic units within a certain range. With the development of satellite remote sensing technology, DEM data are widely used in large-scale structural geomorphic research, such as the study of geomorphic parameters of orogenic belts. In recent years, with the further development of space exploration technology, a large number of high-quality DEM data have been produced. Based on these data, whether the geomorphic indexes methods which have been widely used in large-scale geomorphology research could be applied to small-scale geomorphology to extract more precise structural and geomorphic information has become an important issue of quantitative geomorphology research. In this paper, Dushanzi anticline in northern Chinese Tianshan foreland is taken as the research object to explore the application of geomorphic indexes methods to the study of small-scale geomorphology. Dushanzi anticline is a propagation fold formed in the foreland of Tian Shan Mountains as a result of the India-Eurasia collision and is still active since the Holocene. The geological outcrop of the Dushanzi anticline is about 90km². There are river channels which are well preserved on the anticline, providing an ideal area for the calculation of geomorphic indexes. Consequently, the area is an ideal place for the study of the application of geomorphic indexes methods in the small-scale geomorphology. Based on the 12.5m spatial resolution DEM from ALOS(Advanced Land Observing Satellite), we calculated the HI, k_sn and relief of the study area to explore their applicability to the study of small-scale geomorphology and then the geomorphic parameters are comprehensively analysed to discuss the structural and geomorphic information of anticline. The results indicate that: 1)In the quantitative study of small-scale geomorphology, the lower level drainage basins should be used to generate the HI on the premise of the accuracy of the data to improve the resolution of the HI results. Invalid data of small drainage basins should be eliminated in the process of calculating k_sn to ensure its accuracy although the density of the data will decrease. The smaller window should be used to calculate the relief on the premise of ensuring statistical error and research demand to improve the resolution of results. The higher resolution of DEM is helpful to improve the resolution and accuracy of the above indexes. 2)The results of geomorphic indexes indicate that the core of the anticline has higher uplift rate, larger erosion amount, smaller volume residual rate, and later stage of geomorphic evolution compared with the inclined end of the anticline and a continuous change of landform from intense down-cutting to topographic relaxation could be observed from the core to the inclined end of the anticline. The calculation results of geomorphic indexes are consistent with the geological facts of Dushanzi anticline, which shows that the geomorphic indexes methods are effective in the study of small-scale geomorphology.

With the development and breakthrough of a series of techniques such as the fault surface morphology measurement, the geochemical element determination and Quaternary dating methods, it becomes possible to study paleo-earthquake using information recorded by the bedrock fault surface. At present, more and more scholars domestic and overseas have carried out a large number of paleo-earthquake studies on bedrock fault surfaces in different professional perspectives and have achieved a series of innovative results. This paper systematically introduces the development history, the current situation and the basic principles and applications of paleo-earthquake study on bedrock fault surface. Moreover, after the thorough discussion of the existing problems in paleo-earthquake research of bedrock fault surface, some suggestions for optimizing the current work are proposed. Finally, on the basis of comparison of the characteristics, advantages and disadvantages of various research methods, the prospects and development trends of the bedrock fault paleo-earthquake study are predicted. Lots of weaknesses and limitations in the current study are pointed out in this paper:Firstly, for the method of faullt surface morphology measurement, different morphological expression parameters exist nowadays, however, their advantages and disadvantages are unknown. Secondly, the TCNs method still has a large uncertainty in the age determination of the paleo-earthquake, and the mature cosmogenic nuclides dating methods is too few to meet the dating requirements of different lithologic fault surfaces. Besides, a reliable relationship between relative dating parameters such as morphologicl and physicochemical characteristics and the absolute dating method such as TCNs are not closely established to build a reliable chronology framework. The last but not the least, the lack of mechanical research on the physical and chemical biological processes that the bedrock fault surface experienced before and after the faulting and exposure, and insufficient multi-method comprehensive comparison are also the obstacles for the paleo-earthquake study on bedrock fault surface. It is suggested that in the future study of paleo-earthquakes on bedrock fault surfaces, more attention should be paid to the following aspects:Firstly, strengthen the evaluation of the reliability, applicability and accuracy of the parameters of each morphological model in time and improve the mathematical model of current dating techniques, optimize the mechanism of cosmogenic nuclide production, and introduce new high-precision dating technology timely; Secondly, strive to establish a reliable age framework between relative dating index(X)and absolute dating age(T)regionally; In addition, the morphological structure and mineral compositions of bedrock fault surface are analyzed proactively on the microscopic scale, and the mechanical study is conducted on a series of physical, chemical and biological processes that the fault surface experienced before and after the exposure. At last, comprehensive and comparative research need to be conducted by the multi-disciplinary and multi-method approaches. In conclusion, the paleo-earthquake study on the bedrock fault surface is going through the processes from the qualitative description to the quantitative expression, from the single-disciplinary method to the multi-disciplinary integration, from the exploration of a certain technical index to the comprehensive application of multi-source data technology. The combination of relative dating indicators(X)and absolute dating(T), and putting more emphasis on the mechanical study on the microscopic scale are the development trends of paleo-earthquake study on the bedrock fault surface. The close combination of the paleo-earthquake study of the bedrock fault surface with the traditional method of trenching conducted in the Quaternary sediment region is considered to help more effectively reconstruct a more complete paleo-earthquake sequence and the faulting history on the active fault zone, thus a more reasonable evaluation of the regional seismic hazard can be obtained.