# Integrated Earthquake Catalog of the Eastern Sector of the Russian Arctic
## 3 Results
### Magnitudes in the Integrated Catalog of the Eastern Sector of the Russian Arctic
\begin{tabular}{c} Very unreliable correlation. Only three events with two marginals were found, \(\text{h}^{\text{YAFS}}\) = \(m\)JSC \\ \end{tabular}  \\ \hline ANF & ML & 4 & 2 & \(M=M\)JSC \(-1\) & & 42-4.3 &
\begin{tabular}{c} Very unreliable correlation. Found only two events with two magnitudes, \(\text{h}^{\text{YAFS}}\)\(>\)\(>\)\(>\)\(>\)\(>\)\(>\)\(>\)\(>\)\(>\)\(>\)\(<\)\(>\)\(<\)\(>\)\(<\)\(At present, the only physical magnitude scale is the seismic moment-based magnitude \(M_{\rm W}\), which is preferable when analyzing estimates of different magnitude scales [37; 38]. However, when moving from large to small magnitudes (from global estimates to regional ones), discrepancies in \(M_{\rm W}\) estimates are observed everywhere at \(M<5.0\)[39; 40]. It should be noted that the Eastern Arctic region was not considered in [39]. In the present work, we use only global estimates of the \(M_{\rm W}\)\({}^{\rm GCMT}\) magnitude. If the global estimate of moment magnitude is unknown, we prefer the magnitude \(mb^{\rm ISC}\), which is used by ISC in its practice to obtain \"quasi-\(M_{\rm W}\)\" estimates in the range \(M<5.0\)[41]. A feature of the catalogs used is the presence of estimates of energy classes, and not magnitudes. Theoretically, the energy class estimate proposed by [PERSON] [42] was assumed to be the same physical parameter as the radiated seismic energy, or moment magnitude, which was presented later [43]. However, it was shown in [40] that, in practice, the Rautian energy classes are rather a magnitude characteristic (with its saturation) than a physical one. It should also be noted that there are two approaches for index in the energy class abbreviation. It can be \"\(K_{\rm F}\)\", \"\(K_{\rm F}\)\", or \"\(K_{\rm S}\)\" for Rautian, Fedotov, or Solov'ev, respectively, or \"\(K_{\rm F}\)\", \"\(K_{\rm S}\)\", or \"\(K_{\rm S}\)\" for the wave type, which were used for calculation. In this paper, we stand for the second approach to emphasize the difference in energy class scales. Therefore, the estimates expressed in energy classes were converted to \(M_{\rm W}\) using regression relations. In the studied territory, the number of earthquakes with the known magnitude \(M_{\rm W}\)\({}^{\rm GCMT}\) is small, so regressions with the magnitude \(mb^{\rm ISC}\) are built, which is well aligned with \(M_{\rm W}\)\({}^{\rm GCMT}\)[41]. It is necessary to notice that about 7% of the events in the integrated catalog have other types of magnitudes. If an event has several magnitudes, then preference was given to those for which it is possible to construct a correlation with magnitude \(mb^{\rm ISC}\). In few cases, when there were no pairs to determine direct correlations to \(mb^{\rm ISC}\), we used indirect correlations with other magnitudes, and we consider these correlations unreliable (indicated in the \"Note\" column of Table 4). The 95% confidence intervals are constructed by the Grapher Golden Software built-in tool ([[https://www.goldensoftware.com/products/](https://www.goldensoftware.com/products/)]([https://www.goldensoftware.com/products/](https://www.goldensoftware.com/products/)) grapher, (accessed on 20 March 2022)). Thus, we adhere to the following priority when choosing the optimal magnitude estimate:  
1. \(M_{\rm W}\)\({}^{\rm GCMT}\) or \(M_{\rm S}\)\({}^{\rm ISC}\) for strong earthquakes before 1976;
2. \(mb^{\rm ISC}\);
3. Magnitude by energy class; and
4. Other magnitudes. Statistics on magnitudes in the integrated catalog are given in Table 4.  
Figure 13a shows the correlation between the \(M_{\rm W}\)\({}^{\rm GCMT}\) and \(mb^{\rm ISC}\) magnitudes in the studied territory (\(mb=0.99M_{\rm W}+0.03\)). Earthquakes with an \(M_{\rm W}\) of \(<\)6.0 were used to construct the best linear approximation. For stronger earthquakes, the magnitude \(mb\) saturates and becomes smaller than \(M_{\rm W}\). The magnitude \(M_{\rm S}\approx M_{\rm W}\) is used for earthquakes with an \(M_{\rm W}\) of \(\geq\)6.0.