DDLAFS — QGIS plugin for dominant directions of the local active fault system estimation

Abstract

QGIS is a widely used open-source geographic information system. DDLAFS is a specialized plugin in Python to solve thematic problems. The plugin is designed as a set of functions allowing to calculate the dominant directions of the regional active fault system ψi. The estimation of the dominant directions of the local active fault system is given within a circular area ∆R, where R is a user-defined radius. The centres of regions ∆R should be represented by a set of point objects {g}. These may be epicentres of main shocks, seismogenic nodes, regular grid points, etc. If {g(M)} is represented by data on seismic events, R(g) can be determined depending on the magnitude M of a certain earthquake. The plugin provides an estimate of R(M) using the dependence [11]. For one area, n dominant directions can be determined, each of which corresponds to an empirical value of the probability density distribution of azimuths of active faults, {ψi, pi | i = 1, ... n; ∑pi = 1}. The DDLAFS plugin is designed as part of an anisotropic seismic model in terms of macroseismic intensity [6].