Spatial distribution of clustered seismicity in Khibiny Montains

<p>Using long-term mining-induced earthquake statistics of the Khibiny Mountains (Kola Peninsula, Russia) we studied the spatial peculiarities of clustered seismicity. To declutter the earthquake catalog, we used the nearest neighbor method by Zaliapin and Ben-Zion, 2016, DOI: 10.1093/gji/ggw300. It was shown that the distribution of distances from triggering event to triggered earthquakes obeys a power law with a parameter independent of the trigger magnitude. This result is consistent with distribution of mainshock-aftershock distances obtained for tectonic seismicity by many researchers (e.g., Huc M., Main, DOI: 10.1029/2001JB001645; Felzer and Brodsky, DOI: 10.1785/0120030069; Richards-Dinger et al., DOI: 10.1038/nature09402). Combining the spatial power distribution and the law of earthquake productivity by Shebalin et al. 2020 (DOI: 10.1093/gji/ggaa252), confirmed for the seismicity of the Khibiny Mountains (Baranov et al., 2020, DOI: 10.1134/S1069351320030015) we derived a distribution of maximal distances from trigger to triggered earthquake.</p><p>Using this distribution, we suggest a probabilistic model of zone where triggered earthquakes are expected. The zone is a cylinder centered on the trigger hypocenter, its size (radius and height) depends on the probability of containing triggered earthquakes. The model validation was performed using Molchan’s error diagram. Applying the method of three strategies (Baranov and Shebalin, 2017, DOI: 10.1134/S1069351317020021) to the error diagram, we identified three limiting points on the error trajectory, corresponding to "soft," "neutral," and "hard" strategies. These strategies reflect the prediction importance.</p><p>The research was supported by Russian Foundation of Basic Research, Project No 19-05-00812.</p>

Performance Analysis of Advanced Decision Forest Algorithms in Hyperspectral Image Classification

In this study, the performances of random forest (<small>RF</small>), rotation forest (<small>RoF</small>), and canonical correlation forest (<small>CCF</small>) algorithms were compared and analyzed for classification of hyperspectral imagery. For this purpose, the Airborne Visible/Infrared Imaging Spectrometer (<small>AVIRIS</small>) Indian Pine (<small>IP</small>), the Reflective Optics System Imaging Spectrometer University of Pavia, and the AVIRIS Kennedy Space Center (<small>KSC</small>) data sets were used as main data sources. In addition to the confusion matrix–derived accuracy measures (overall accuracy, kappa coefficient, F-scores), the performances of the algorithms were analyzed in detail considering three diversity measures (Q statistics, correlations, and interrater agreements) and a kappa-error diagram. Results showed that the highest classification accuracies (87% for IP, 94% for PU, and 93% for KSC data sets) were achieved with the use of CCF algorithm, and improvements in classification accuracy were statistically significant compared to RF and RoF. Based on the diversity measures and the kappa-error diagram, individual learners in the CCF ensemble were found to be more diverse and accurate.

ANALYSIS OF DEFECTS AND FAILU RES OF HYDRAULIC GEAR PUMPS WITH THE USE OF SELECTED QUALITATIVE METHODS

The paper presents an analysis of the defects and failures of a gear pump using the FMEA matrix analysis and error diagram. For each pump component, functions that are performed and potential defects were identified. Failures and defects that are typical for gear wheels were found as the main problem that influences pump malfunction. Therefore, using the error diagram, the main categories of causes were determined. In the next step, the identified causes and subcauses were assigned to defects with the highest possibility of occurrence, which allowed us to specify preventive and corrective actions.

Testing the forecast of aftershocks: a simple method with an example of application

Tests of aftershock forecast have to consider the temporal distribution of aftershocks, which differ from mainshocks. This paper uses as an example the 2008 Wenchuan aftershock sequence and the load-unload response ratio forecast of aftershocks. We discuss a simplified test scheme using the Ogata-transformed time to make the transformed aftershock sequence homogenously random. While an example was taken using the Molchan error diagram, other testing schemes are also valid for the transformed aftershock sequence.

On the Analogy Between the Calorimeter Problem and Some Granulate-Fluid Exchange Processes

The solution to a generalized version of the classical calorimeter problem approximates the behavior of certain continuous exchange processes between particulate solids and a fluid. For modeling purposes, the much simpler energy-balance solution has obvious advantages, although it only holds for negligible intraparticle resistance and thus predicts too short contact times. An error diagram provides a quantitative comparison between those two results as a function of the two pertinent system parameters.