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Research of WenChuan Earthquake Zone’s Structural Feature and Equilibrium Effect

Author: MaGuoQing
Tutor: MengLingShun
School: Jilin University
Course: Solid Earth Physics
Keywords: Wenchuan earthquake walsh filter Three directions Extensions Hartley transform A first derivative Cosine filter factor Fracture morphology Equilibrium effects
CLC: P631.4
Type: Master's thesis
Year: 2010
Downloads: 91
Quote: 1
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Abstract

Wenchuan after the earthquake , on the eastern edge of the Longmen Shan region tectonic deformation performance , deep structure , and other issues of geodynamic processes geologists once again aroused widespread concern . Fault zone in the Himalayas and Yang squeeze splicing block intersections , since a freshman with a strong fold uplift area. The complex topography of the study area for data collection and processing work has brought great difficulties , the use of advanced equipment to ensure the quality of data collection , so the precision of the data processing method development is necessary. For filtering, edge, such as expanding methods to improve data quality improvement , application walsh filter for data filtering and field separation operation, and propose three methods to achieve direction Extensions Extensions data processing , maximize the retention of boundary information . Hartley transform is derived based on the weight of ( magnetic ) abnormal spectrum, and the first derivative of the formula , Hartley transform is more symmetrical than the Fourier transform and calculate the real field , so that the method is faster , more accurate , and the use of theoretical models the test results show that the method derivative calculation accuracy is significantly higher than the Fourier transform , with the theoretical value of the difference is small. Euler deconvolution method and the normalized total gravity gradient method is now more commonly used method of inversion , so this paper, these two methods in the area before and after the earthquake, the earthquake fracture morphology to be divided, and the Hartley transform the derivative calculation method is introduced to deal with these two methods to improve the accuracy of its inversion , the traditional normalized total gravity gradient method SMOOTHING FILTER - sine filter factor decurrent poor stability, to address the problem raised cosine filter factor to enhance the stability under the extension , and in the practical application of manipulation filter factor varies with depth with nature , and achieved good results. From before the earthquake and after the earthquake fracture morphology contrast can be seen in the release of stress due to the earthquake , which after the earthquake rupture thrusting nappe effect decreases, and look out for the earthquake caused by the fracture zone of the location , the measurements at Dujiangyan - Jiangyou fault east discovered a new fracture. Finally, the analysis of the balance of the region after the earthquake anomalies , and using Parker-Oldenburg conducted Moho depth calculations.

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