| Yunnan is an area with high seismic frequency, strong magnitude, wide earthquake distribution, and heavy earthquake disaster. Because of its long historical records of earthquake death toll and abundant, accurate earthquake cases, Yunnan becomes one of the most important regions for the research of the earthquake-caused death. Strengthening the research of the earthquake-caused death, studying the features of the earthquake- caused death and probing the regularity of the earthquake-caused death in Yunnan are theoretically and realistically significant for prediction of the degree of the earthquake-caused death, estimation of the risk of earthquake-caused death, and mitigation of the disaster of earthquake -caused death.Aiming at the feature, the model, and the evaluation of the earthquake-caused death, the author systematically investigated, collected, and sorted out the data of earthquake-caused death, then studied the characteristics of the time, space, strength of earthquake-caused death as well as the sociological feature and the effective feature of the factor of the earthquake-caused death by the method of statistics of earthquake cases. According to the earthquake-caused death factors in different periods in history in Yunnan, and using the multiple regression method, the author built the regression model for the following 7 factors of earthquake-caused death such as different parts, different magnitudes, different intensities, different original times, different population densities, different area of intensities and all types of economic indexes, to reveal the relation between the total earthquake death toll and the earthquake -caused death factor. For a single earthquake event, through empirical ascription method, area cutting method, and population inversion method, the author built the town level and theⅥllage level model of intensity-earthquake-caused death ratio and realized the spatial express for the administrative town unit for the earthquake-caused death. According to the national requirement for the earthquake emergency, genesis and evolvement of the strong earthquakes, and pre-estimation of social economic development trend, on the basis of the population and social economy in the year of 2015, the author made a prediction of the earthquake-caused death. Further, on the condition of would-be-encountered intensity, the author pre-estimated the earthquake -caused death risk in Yunnan through GIS techniques and got 9 results. Finally, the author preliminarily discussed 3 questions which still need further study.The recordings in history in Yunnan can be classified into the following 4 periods according to the earthquake event, earthquake-caused death, and the influence factors. The first period is from 886 A.D. to 1899 A.D. In this period, there are many omissions of the recordings of the earthquake events and earthquake-caused death. So the data in this period can only be used to macroscopically comprehend time, space, and strength of the historical earthquake-caused death. The second period is from 1900 to 2000. In this period, there are still some omissions of the earthquake events and the earthquake-caused death, but the recordings are generally reliable. The earthquake-caused death factors are few. The third period is from 1950 to 2000. In this period, the recordings of the earthquake-caused death are more accurate. There are complete earthquake-caused death factors such as the earthquake death toll, original time, magnitude, degree of area, and the intensity region, number of the population in the disaster area, density of the population in the disaster area, the earthquake death toll in the administrative units on different levels. The fourth period is from 1993 to 2008. In this period, all kinds of the recorded data are accurate. And the earthquake-caused death factors are complete, including sociological factors and economic indexes in the disaster area. But the pity is that the number of the sample of strong earthquakes causing high intensity is few.There is a very high level of earthquake-caused death in Yunnan. In the period from the 16th century to the 19th century, the recorded data of earthquake-caused death in each century is between 5000 and 10000. The average level was still very high. Although many earthquakes are not recorded, the average earthquake-caused death level is high. In the 20th century, the number of the earthquake-caused death was 30079, which is obⅥously higher than those of other centuries. This is perhaps because of the relatively complete recordings of the earthquake events and the earthquake-caused death and constantly-rising population in the 20th century.In Yunnan, the distribution of earthquake-caused death in the east part is very different from that in the west part. The most serious cases of earthquake-caused death occurred in east Yunnan. The secondary one occurred in west Yunnan, the lightest one in southwest Yunnan. From 886 A.D. to 1899 A.D., there were 8 earthquakes which caused over 1000 people’s death in Yunnan. Among these earthquakes, 6 occurred in east Yunnan, causing 23748 people’s death, amounting to 73% of the total. 2 occurred in west Yunnan, causing 8900 people’s death, amounting to 27% of the total. From 1900 to 2000, there were 11 earthquakes which caused over 100 people’s death in Yunnan. Among these earthquakes, 6 occurred in east Yunnan, 4 occurred in west Yunnan, 1 in southwest Yunnan. Further, earthquakes caused the most serious death were also not well-distributed in each of the 3 parts; in east Yunnan, the earthquakes were mainly distributed in Yuxi city, north part of Honghe prefecture, north part of Kunming city, north part of Zhaotong city. In west Yunnan, the earthquakes were mainly distributed in the west of Pu’er city.The earthquake-caused death was controlled by the active period and the main active area of strong earthquakes, so the earthquake-caused death area mainly occurred in the main active area and in the active period of strong earthquakes. For example, in the active period in east Yunnan, the main active area of strong earthquakes, the number of earthquake-caused death is between 10000 and 20000. But in the active period in west Yunnan, another main active area of strong earthquakes, the number of earthquake-caused death was only 1000 or so. In the 20th century, the number of earthquake-caused death in 4 active periods amounts to 96.7% of the total. In the same one earthquake active episode, the earthquake-caused death is mainly in the active period of the active episode. In the first active period, the number of the earthquake -caused death is 9907, amounting to 98.6% of the whole episode. In the second active period, the number of the earthquake-caused death is 1412, amounting to 70.6% of the whole episode. In the third active period, the number of the earthquake-caused death is 17602, amounting to 97.8% of the whole episode. In the fourth active period, the number of the earthquake-caused death is 1140, amounting to 97.5% of the whole episode. In the first and the third active period in east Yunnan, the number of the earthquake-caused death is the most, amounting to 89.8% of the total in the 20th century and 92.8% of the total of the 4 active periods. Along with the repeated migration of the strong earthquakes in the east and the west part of Yunnan, the spatial distribution of the earthquake-caused death repeated in the east and west part of Yunnan.For a single earthquake event, the number of earthquake-caused death is affected by multiple factors. Among them, magnitude and intensity are the dominant ones. For example, in the 20th century in Yunnan, the number of the M≥7.0 earthquakes amounts to 3.8% of the total, but the number of the earthquake-caused death amounts to 87%. The number of the earthquakes causing intensity ofⅨin the meizoseismal area is 15, amounting to 7.4% of the total, but the number of the earthquake-caused death amounts to 96%. So the author concluded that the average number of the earthquake-caused death and the largest number of the earthquake-caused death are both in an exponential relation with magnitude and intensity in the meizoseismal area. In addition,population density is another important factor influencing the earthquake death toll. For example, the statistics of the 106 earthquakes since 1950 shows that for the same one intensity area, the number of earthquake-caused death of the high density population is 1.09～9.33 times of that of the low density population. And the average is 1.32. The original time is also an important factor affecting the earthquake-caused death. For example, from 1900 to 2008, for 18 pairs of similar earthquakes, the death toll in the nighttime was 1.14～22.5 times of that occurred in daytime. The average is 7.17. The economic factor also has a significant effect on the ratio between the different structural buildings. For example, the standardized estimation of the earthquake disaster was carried out in 1993. So far, the disaster of 29 earthquakes has been estimated. The results showed that if the per capita net income of the farmer, the revenue of the government, and the GDP per capita go up to a higher grade, the ratio of ciⅥl-structure buildings will go down for 3%～10%, and the ratio of bricky-timberwork buildings will rise 1%～10 %, but for the brick- and- concrete Structure , the ratio rises little.In Yunnan, the earthquake-caused death has its unique sociological characteristics. Sociological investigation showed that the ratio of the earthquake-caused death of the farmer, the female, the old, the children, the ethnic people, the illiterate and the poor-educated is 3%～26% higher than the average ratio. This is the feature of the earthquake-caused death in Yunnan, and perhaps the feature of the earthquake-caused death of the disadvantaged groups.The total of the earthquake-caused death can be expressed by different earthquake-caused death factors, different earthquake-caused death area, different classifications of the magnitude, and different models in different periods. In this paper the author built multiple mathematical models of earthquake-caused death to depict the coupling relationship between the number of earthquake-caused death and the factors of earthquake-caused death.Through the analysis of the intensity-earthquake-caused death ratio of the Lijiang M 7.0 earthquake in 1996, Lancang M 7.6 earthquake in 1988, Daguan M 7.1 earthquake in 1974, Tonghai M 7.7 earthquake in 1970, Pu’er M 6.8 earthquake in 1979, and Dongchuan M 6.5 earthquake in 1966, the author established an intensity-earthquake-caused death ratio analytical method which goes well with the realities in Yunnan. Finally the author built the typical intensity-earthquake-caused death ratio model on the basis of the town unit and the administrativeⅥllage unit in Yunnan.Through the earthquake-caused death model and the regularity of the growth of population and economy in Yunnan, the author predicted the total of earthquake-caused death on the condition of scenario earthquake,and the given intensity. According to the potential earthquake areas in Yunnan given by The Zonation Map of Earthquake Ground Motion Parameters in China (GB18306-2001), the author pre-estimated the risk of earthquake-caused death in Yunnan. According to the features of historical active trend of the strong earthquakes in future and the result from the pre-estimated risk of the earthquake-caused death in east Yunnan, the north part of Honghe prefecture, north part of Kunming city, and north part of Zhaotong city will be the high-risk regions of earthquake-caused death and need key earthquake monitoring and prevention in 5～10 years in future. |
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