## 2 Data and Data Preprocessing
### Data  
The raw data used in this study are the earthquake catalog data, which include earthquake time, date, latitude, longitude, magnitude, and focal depth. The data can be downloaded from the China Earthquake Networks Center ([[https://news.ceic.ac.cn](https://news.ceic.ac.cn)]([https://news.ceic.ac.cn](https://news.ceic.ac.cn))). Considering the completeness of the earthquake records, using the G-R formula, the minimum completeness magnitude Mc = 3.0. Therefore, only earthquakes with a magnitude of _M_s 3.0 and above were selected for this study. The primary information used includes earthquake time, latitude, longitude, and magnitude. Based on this information, several seismological parameters were calculated, which are introduced in detail below:  
1. \(T\) Value  
This parameter represents the time elapsed for n events with magnitudes greater than or equal to the minimum completeness magnitude in the earthquake catalog before each month arrives. (The parameter is calculated based on the 100 earthquake events that occurred before February 2000. These 100 events are counted starting from the last earthquake in January 2000 and going backward. \(T\) represents the number of days between these 100 earthquake events.) The formula is as follows:  
\[T=t_{n}-t_{1} \tag{1}\]  
where \(t_{1}\) represents the time of the first earthquake and \(t_{n}\) represents the time of the \(n\)th earthquake, with \(n=100\) used in this paper to calculate the time elapsed before 100 earthquake events occur each month. A smaller \(T\) indicates a higher frequency of earthquakes, meaning events are more frequent; conversely, a larger \(T\) indicates a lower frequency of earthquakes, meaning events are less frequent. 2. Average Magnitude  
This parameter represents the average magnitude of \(n\) earthquake events, as given by the following formula:  
\[M_{mean}=\sum M_{i}/n \tag{2}\]  
where \(M_{i}\) represents the magnitude of the \(i\)th earthquake event. It is generally observed that the average magnitude before a major earthquake tends to gradually increase as the major earthquake approaches. 3. The square root rate of the earthquake energy released (\(dE^{1/2}\)) This parameter represents the intensity and frequency of seismic activity, and is given by the following formula: \[dE^{1/2}=\frac{\sum E^{1/2}}{T}\] (3) where \(E^{1/2}\) represents the square root of the earthquake energy (\(E\)), and \(M\) represents the magnitude. The earthquake energy can be calculated using the following formula: \[E=10^{(11.8+1.5M)}erggs\] (4)
4. Slope of the log of the earthquake frequency versus the magnitude curve (\(b\) value) The parameter is based on the G-R inverse power law of earthquake magnitude and frequency, which is expressed by the following formula: \[log_{10}N=a-bM\] (5) where \(N\) is the number of earthquakes with magnitudes greater than or equal to \(M\), \(a\) and \(b\) are constants, and \(b\) is the slope of the approximately linear relationship between the logarithm of earthquake frequency and magnitude. Their calculation formulas are as follows: \[a=\frac{n\sum_{i}^{n}(log_{10}N_{i}+bM_{i})}{n}\] (6) \[b=\frac{n\sum_{1}^{n}M_{i}log_{10}N_{i}-\sum_{1}^{n}M_{i}\sum_{1}^{n}log_{10} N_{i}}{\left(\sum_{1}^{n}M_{i}\right)^{2}-n\sum_{1}^{n}M_{i}^{2}}\] (7)
5. The mean square deviation (\(\eta\)) The calculation formula for this parameter is as follows [36]: \[\eta=\frac{\sum_{1}^{n}(log_{10}M_{i}-(a-bM_{i}))^{2}}{n-1}\] (8) where the lower the \(\eta\) value, the more likely the distribution is to be estimated using an inverse power law; conversely, a higher \(\eta\) value indicates a greater degree of randomness. 6. Magnitude deficit (\(\Delta M\) value) This parameter represents the residual between the observed maximum magnitude in n seismic events and the maximum magnitude based on the G-R law.