# Integrated Earthquake Catalog of the Ossetian Sector of the Greater Caucasus
## 3 Results
### Merging Catalogs
In this situation, the application of the method used in [4; 5] to determine the threshold value of the metric leads to an increased probability of missing duplicates. Therefore, in the present paper the actual distribution of the metric for the nearest events from the two catalogs being merged is used instead of the multivariate normal distribution model. The effectiveness of this approach is shown in [6]. We believe that the maximum metric value for possible duplicate events is \(Ro=30\); this corresponds to the difference in time and space of the order of 1.5 min and 600 km. For such events, the distribution \(F\)dub is constructed. Red lines in Figures 5b, 7b and 9b show the value \(1-F\)dub, which is considered to be the probability of missing a duplicate (error of the I kind). The probability of a false duplicate (error of the II kind) is estimated in the same way as in [4; 5]. For this reason, the values of the metric (1) \(Ro\) between events inside the additional catalog are calculated: blue lines in Figures 5b, 7b and 9b show the fraction of events with proximity less than a given \(Ro\) value. Black lines show estimates of the total probability of errors of the first and second kinds. The threshold value of the metric minimizes the total amount of errors. Figures 5c, 7c and 9c represent the distribution of normalized times and distances for the nearest events from the merged catalogs. The level lines of the metric correspond to the selected threshold value that provides the optimal separation of duplicates and unique events. Figure 5: Stage 2: Merging of catalogs NC and GEOR04. (**a**) Comparison of the metric distribution NC/GEOR04 pairs (blue histogram) and the same metric for GEOR04/GEOR04 earthquakes (red histogram). (**b**) Threshold optimization: the red line shows the probability of missing a duplicate, the blue line shows the probability of a false duplicate, and the black line shows the total probability of first and second kind errors. The threshold value \(Ro=9\), which minimizes the total number of errors, approximately 1.1%, is shown by a dashed line. (**c**) Distribution of normalized \(DT\) and \(DR\), and contour line of metric (1). Colored dots represent NC/GEOR04 pairs (pink dots are duplicates, blue dots are unique events), and black dots are distances between GEOR04/GEOR04 events in metric (1). The values of the metric for earthquakes in the GEOR04 catalog are significantly larger than for NC/GEOR04 duplicates (pink dots). The contour line of metric (1), \(Ro=9\), provides close-to-optimal separation of duplicates and naturally grouped events. Absolute duplicates are not shown. Figure 6: Stage 4: Determination of numerical parameters of the metric (1) for merging the GSR and ISC_OTHER catalogs. Distributions of variables \(DT\), \(DX\), \(DY\), and the dependence of dispersion and mean values on the time and magnitude of events. Figure 7: _Cont._  
Numerical parameters for merging catalogs are presented in Table 3. The compiled catalog of the Ossetian sector of the Greater Caucasus contains 16,286 events. The ISC_CORE catalog contains 45 events that are not in the GSR catalogs (GSR is the integration of Soviet, Russian, and Georgian catalogs; Figure 2). These are quite strong events for which a magnitude \(mb^{\rm ISC}\geq 3.4\) was determined. These events were missing in the GSR catalogs for the following reasons. Three events occurred in 2022, for which GSR catalogs have not yet been published. Six events are in the GSR catalogs, but are located outside the studied region; these six events are included in the integrated catalog because we give preference to determinations from the ISC_CORE catalog. Another event that occurred on 4 August 1989 at 9:22:57 is in the ZEMSU catalog but has a time of 19:22:54, so it was not identified as a duplicate. Most likely this is a technical error in the ZEMSU catalog; we consider this event a duplicate and do not include the definition from ZEMSU in the final integrated catalog.