The system of neotectonic faults in southeastern Altai: orientations and geometry of motion

Abstract

The implications of recent seismological and resistivity data for the geometry and orientations of neotectonic faults are generally consistent with the morphotectonic model of Gorny Altai as an area of crustal failure at the junction of two relatively stable blocks. The model predicts motions under general NW compression mainly on right-lateral strike-slip faults accompanied by systems of pinnate reverse and extensional faults. The locations and mechanisms of aftershocks that followed the 2003 Chuya earthquake (Gorny Altai) indicate long seismic activity generated by a neotectonic NW right-lateral strike-slip fault which separates the North Chuya and South Chuya ranges from the Kurai-Chuya system of intermontane basins. The plane of the northwestern termination of the active fault zone dips in the SE direction, beneath the ranges, at about 70°. MT data show two types of conductors that reach the surface, namely, nearly vertical zones along neotectonic faults between the blocks not involved into vertical motion, according to morphotectonic evidence, and inclined zones between the uplifted (subsided) blocks. We interpret the former as strike-slip faults and the latter as reverse or reverse oblique faults, which always dip beneath the uplifted blocks and record the general compressional setting.

Basin evolution in a folding lithosphere: Altai–Sayan and Tien Shan belts in Central Asia

“…The largest shock (Mw 7.2) generated surface breaks over a total length of about 60 km, aligned along a fault striking 295°E with was activated by right-lateral strike-slip movement with a slight reverse component (Agatova et al, 2004;Nissen et al, 2007;Rogozhin et al, 2003). On the south-western side of the Kurai depression, aftershock distribution shows that the fault plane dips steeply towards the SW under the North Chuya range, confirming the opinion that the southern margin of the Kurai basin is fault-controlled and of ramp-type (Novikov et al, 2008). In contrast, on the south-western side of the Chuya depression, the fault plane dips 55-85°NE under the basin center, causing uplift of the basin floor relative to the adjacent mountain range.…”

Block Structure of the Southern Kurai Basin of Gorny Altai According to Geoelectric Data Compared to the Distribution of Earthquake Epicenters

“…Ештыкельский прогиб ограничен северным и южным разломами, выделенными специалистамигеологами в результате анализа распределения гипоцентров афтершоков Чуйского землетрясения 2003 г. [Novikov et al, 2008[Novikov et al, , 2014Novikov, Pospeeva, 2017]. По данным ЗС 2010-2011 гг., в этом прогибе получены значительные глубины до фундамента, превышающие 1000 м .…”

“…Построенные по новым данным геоэлектрики разрезы подтверждают вывод о том, что Ештыкельский грабен ограничен с севера и юга разломами, которые предполагались специалистамигеологами при анализе распределения гипоцентров афтершоков Чуйского землетрясения 2003 г. [Novikov et al, 2008].…”

Complex Electromagnetic Monitoring of Geodynamic Processes in the Northern Tien Shan (Bishkek Geodynamic Test Area)

“…Наиболее крупными структура-ми региона исследований являются (с севера на юг): Иссык-Атинский, Чон-Курчакский и Шамси-Тюндюкский разломы, положение которых неоднозначно у разных авторов [Thompson et al, 2002;Bullen et al, 2003;Mikolaichuk et al, 2003;Laverov, Makarov, 2005]. При этом Научная станция РАН (НС РАН) имеет значительный опыт изучения разломных структур, в том числе и скрытых, или зон динамического влияния разломов как на территории Бишкекского геодинамического полигона, Алтайского сейсмологического полигона, так и на сопредельных территориях [Bataleva, 2005[Bataleva, , 2016Bataleva et al, 2006aBataleva et al, , 2006bBataleva et al, , 2017Buslov et al, 2007;Novikov et al, 2008;Batalev et al, 2013;Bataleva, Batalev, 2015]. Использование современных подходов Рис.…”