PRESENT-DAY GEODYNAMICS AND SEISMICITY OF ASIA MINORD. V. Rundkvist and I. M. Rotwain
We study systems of tectonic displacement (faults, zones of plastic flow and deformation) involved in the preparation of large earthquakes on the time scales of one to three years that are relevant to intermediate-term earthquake prediction. We examine the central part of the Alpine-Himalayan Tethys belt including the Dead and Red Sea rifts, Gulf of Aden, the Zagros, the Lut block, the Kopet Dag, the Caucasus, and the trans-Caucasian region. We selected those systems where the CN algorithm had identified the appropriate set of earthquake precursors. In contrast to regions that are commonly considered in tectonic regionalization which usually identifies historically related features of arcuate and linear fold structures and fault systems, more complex systems of failure are involved in the preparation of large earthquakes. These include triple rift junctions together with splaying transform faults (Red Sea, Jordan-Dead Sea Rift); arcuate systems of folded nappe structures combined with radial fault zones (Kopet Dag, North Caucasus) or incipient subduction-type features (Zagros, Taurides, Cyprus); spiral strike slip systems that bound rigid blocks (Lut). Screening fault systems are identified which to some extent separate stress fields in adjacent blocks. The Arabian plate is considered to be the leading structural feature that controls block interaction during the present-day movements of this part of Tethys.