## 5 Microtremor Analysis of the Earth Fissure Sites  
Figures 6-10 show the results of the microtremor spectrum analysis of the five survey lines. Figures 6 and 7 show the results obtained from the S1 and S2 survey lines on the F\({}_{1}\) earth fissure site, respectively. Figure 8 shows the result of the F\({}_{2}\) fissure site, and Figures 9 and 10 show the spectral results of the F\({}_{5}\) earth fissure site. Figure 5: Schematic diagram of microtremor testing. (A represents hanging side, B represents heading side, M represents Measurement point, also in the following figures). Figure 8: Fourier spectrum, response spectrum, and Arias intensity analysis results for line S3. Figure 6: Fourier spectrum, response spectrum, and Arias intensity analysis results for line S1. Figure 7: Fourier spectrum, response spectrum, and Arias intensity analysis results for line S2. The Fourier spectral results show that the same earth fissure site yielded consistent Fourier spectral features, while the spectra patterns from different fissure sites were distinctive. As can be seen from Figures 6 and 7, the Fourier spectrum patterns of the F\({}_{1}\) earth fissure site are dominated by'single-peak' spectra, with small spectral areas, prominent main peaks, and narrow spectral energy distribution intervals. From Figures 8-10, it can be seen the Fourier spectra of the F\({}_{2}\) and F\({}_{3}\) fissure sites are both broad and dominated by'multi-peak' spectra, with more secondary peaks and a relatively wide range of spectral energy distribution. The Fourier spectral pattern is dependent on the fissure site, with the F\({}_{1}\) fissure site having relatively hard soil conditions, dominated by interbedded loess and paleosol. The F\({}_{2}\) and F\({}_{5}\) fissure sites have different site conditions, but the profiles reveal that the two sites have similar soil conditions, dominated by silty clay intercalated with silt, with a relatively weak soil layer. Therefore, the Fourier spectral patterns of the earth fissure sites F\({}_{2}\) and F\({}_{5}\) are similar, and they are significantly different from the Fourier spectral characteristics of the F\({}_{1}\) site. Figure 10: Fourier spectrum, response spectrum, and Arias intensity analysis results for line S5. Figure 9: Fourier spectrum, response spectrum, and Arias intensity analysis results for line S4. Further analysis of the predominant frequencies revealed that the presence of earth fissures had little effect on the predominant frequencies of the site. This means that the predominant frequencies of the same survey line did not change significantly with increasing distance from the earth fissures, and the ranges of the predominant frequencies on the hanging and heading sides were basically the same. From the results of the spectral analysis, it can be concluded that the predominant frequency of the F\({}_{1}\) earth fissure site is 6-7 Hz, that of F\({}_{2}\) is 3-5 Hz, and that of F\({}_{5}\) is 3-5 Hz. However, because of the different soil structures of different earth fissure sites, the predominant frequencies of the different sites are different. The response spectra of the same fissure sites were also generally consistent, with all three types of fissure sites showing a predominantly'single-peak' response spectrum, with prominent main peaks and few or no secondary peaks. Similar to the results of the Fourier spectrum analysis, the response spectrum of the F\({}_{1}\) fissure site was the narrowest among all of the fissure sites, while the F\({}_{2}\) and F\({}_{5}\) fissure sites revealed a similar response spectrum with a slightly larger spectral area than that of F\({}_{1}\). All three fissure sites had a relatively concentrated predominant period, which was distributed in the interval of 0-0.5 s.  
The Arias intensity is the curve of the energy accumulation at the measurement point over time. The difference between the energy of the different measurement points can be seen better from the final accumulated energy.