World map of active faults (preliminary results of studies)

Abstract

Abstract The Project ‘World map of major active faults’ was confirmed in 1989 as a part of the International Lithosphere Program. The objectives are to compile the World map in scale 1:10,000,000, the maps of continents in scale 1:5,000,000 and the maps of some seismic regions in scale of 1:1,000,000 or 1:5,000,000 with the Explanatory Notes and the Catalogue of major active faults of continents. The maps will show location, age, sense and rate of motion and reliability of identification of faults not older, than 100,000 years, as well as Middle Pleistocene faults, contemporary folds, flexures, volcanoes and epicentres of strong earthquakes differentiated by magnitude, depth and age. The first results of the Project are discussed. One of them is predominance of the strike-slip component of motion over the vertical one for the majority of continental active faults. It has occurred because the strike-slip motion is more efficient, than the thrust, the reverse and even the normal ones. Strike-slip faults are differentiated into faults of translation, rotation and squeezing. The contribution of seismicity to faulting depends on the inpulse, the creep and the inpulse-creep regimes of recent motion in the fault-zones. Different geological techniques for estimating the motion regime, the magnitudes and the recurrence interval of strong Holocene earthquakes are discussed.