## 4 Results
### Identification of Factors Contributing to Human-Caused Fires  
By employing PCA and correlation coefficient matrices, we gained insights into the relationship between each factor and fire incidents. The correlation coefficients of potential fire factors with fire are depicted in Figure 4. As shown, Factor 1 denotes the fire density over the past 10 years and displays positive correlations with other factors. Notably, the highest correlation, reaching 0.77, is observed between Factor 7 (proportion of buildings over 40 years old) and Factor 1 (fire density over the past 10 years). The positive correlations observed between fire density over the past 10 years and other factors, such as the high correlation of 0.77 between Factor 7 (proportion of buildings over 40 years old) and Factor 1 (fire density over the past 10 years), suggest potential relationships between these variables. One hypothesis could be that older buildings are more susceptible to fires due to aging infrastructure, outdated electrical systems, or other factors associated with older constructions. As buildings age, they may become more prone to fire incidents, leading to higher fire densities in areas with a greater proportion of older structures [52; 53]. This hypothesis implies that the age and condition of buildings play a significant role in determining the frequency of fire incidents, which could inform urban planning, building maintenance, and fire prevention strategies [54]. Figure 3: The schematic flowchart diagram illustrating the process of this study. Based on the PCA findings in this study, it is found that a heightened proportion of buildings aged over 40 years per unit area may contribute to an increased risk of fire incidents. This is primarily due to various factors associated with aging structures. Older buildings often showcase outdated electrical systems, deteriorating wiring, and structural materials, making them more vulnerable to faults and potential fire hazards. Moreover, the absence of modern fire-resistant materials and technologies in these structures reduces their ability to withstand or mitigate fire events. The accumulation of these contributing factors within a defined area, indicated by a higher proportion of older buildings, amplifies the overall risk of fire incidents in the specified geographical space. Additionally, noteworthy correlations with an increased frequency of fire incidents were observed for Factor 11 (proportion of tertiary sectors of the economy) and Factor 3 (proportion of elderly population) at 0.73 and 0.70, respectively. The results indicate that the \"proportion of tertiary sector of the economy\" and the \"proportion of elderly population\" may also contribute to an elevated risk of fire incidents for distinct reasons [12; 13; 14]. Moreover, it appears that the positive correlations observed between fire density over the past 10 years and factors such as Factor 2 (population density), Factor 6 (building density), and Factor 10 (proportion of the secondary sector of the economy) can be attributed to several potential factors. Areas with higher population densities often experience increased human activity, which may lead to a higher likelihood of fire incidents due to factors such as cooking, heating, and electrical usage [29]. Higher building densities can result in a higher concentration of potential fire hazards, such as electrical systems, heating appliances, and combustible materials, increasing the risk of fire incidents [55]. The secondary sector, which includes manufacturing and industrial activities, may contribute to fire risk due to the presence of industrial processes, machinery, and chemicals that can pose fire hazards [56]. These factors collectively contribute to the positive correlations observed between fire density and the mentioned variables, indicating that areas with higher population and building densities, as well as a larger proportion of industrial activities, are more susceptible to fire incidents. Figure 5 illustrates the correlation coefficients between each factor.