SEISMIC INTENSITY EVALUATION MODEL IN MEIZOSEISMAL AREA BASED ON FOCAL DEPTH |
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| Authors: | NIE Gao-zhong XU Jing-hai |
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| Affiliation: | 1. Institute of Geology, China Earthquake Administration, Beijing 100029, China;
2. College of Geomatics Engineering, Nanjing University of Technology, Nanjing 210009, China |
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| Abstract: | China is the country with the challenge of severe earthquake disaster. In order to mitigate the disaster and save lives, emergency response and rescue work after an earthquake are deployed and led by the Chinese governments at all level, the effectiveness of which has been proved. In such work, how to quickly evaluate the seismic intensity in meizoseismal area is a crucial issue at the early period after the earthquake. It is the foundation to estimate the disaster losses and decide the scale of rescue teams and materials. However, at the early period only a few physical parameters of the earthquake can be acquired and some of them may even be inaccurate.
An evaluation model of seismic intensity in meizoseismal area is investigated and presented by statistic method in this study. After an earthquake there are four authoritative parameters officially released by China Earthquake Administration generally within ten minutes:earthquake magnitude (MS), focal depth, latitude and longitude position, and the occurrence time. They are good candidate input parameters of the evaluation model. We collect the information of 215 historical earthquake occurring in China from 1966 to 2013, including:The four parameters and the seismic intensity in meizoseismal area. Through statistical analysis we find the seismic intensity in meizoseismal area has high correlation with the earthquake magnitude (MS) and the focal depth and then select them as the formal input parameters. After further investigation a generalized linear model is built to fit the relationship between the seismic intensity in meizoseismal area, earthquake magnitude (MS) and the focal depth.
The effectiveness of the model is validated by the Sig value and F value from theoretic perspective. The validation also includes the application of the model in real earthquakes occurring from 2014 to 2017. After the earthquakes, the seismic intensities in meizoseismal area have been quickly estimated and used in the command of national earthquake disaster emergency relief. The applications in real earthquakes get good results.
Finally, the robustness of the model is analyzed. We respectively verify the influences of the earthquake magnitude (MS) and the focal depth and find the seismic intensity in meizoseismal area is more sensitive to the earthquake magnitude. Under the condition of the same focal depth, when the change of the earthquake magnitude is up to 0.5, the change of the seismic intensity will reach to 1. However, in order to cause same change of the seismic intensity, the difference of the focal depth will be 10 kilometers. Basically, these changes derived from the model meet the situation of historical earthquakes. |
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| Keywords: | earthquake emergency seismic intensity in meizoseismal area seismic intensity evaluation model |
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