This expedition is very useful for seismologists or geologists of theorists who have already acquired in the university the theoretical knowledge about the processes taking place inside the earth’s crust. This expedition will allow to observe and study the results of seismic and tectonic processes and phenomena directly in natural field conditions. During the expedition we will conduct several excursions in various regions of the Tien Shan.
The purpose of the expedition is: familiarization of the course participants with manifestations of seismic deformations in the relief, which were formed by historical and more ancient catastrophic earthquakes. Specialists of different levels will be able to see modern morphostructures that were formed as a result of modern slow tectonic processes and abrupt seismic phenomena.
It is assumed that most of the expedition members have never seen what active faults and deformations look like in nature. They know how to decode seismograms or digital records, but they have never seen the manifestation of strong earthquakes in the relief or on architectural structures.
We decided to give you the opportunity to go on a professional expedition to demonstrate that monitoring seismological observations should necessarily be supplemented by field studies. We decided to show you that the main tasks of seismology should also be solved during field seismogeological research. During this expedition the seismologist must answer four main questions:
- Are the structures observed in the relief structure caused by seismic processes?
- Where was the epicenter of the earthquake;
- To determine the strength of the earthquake, to assess its energy and importance;
- Set the estimated time of the earthquake.
These data are necessary for determining the periods of repeatability of strong earthquakes, active fault segmentation, seismic zoning, etc. In fact, these data will lead us to the solution of long-term earthquake prediction issues: where, when and how strong an earthquake can occur.
Therefore, the Tien Shan in this respect is an excellent educational and scientific-applied seismic and tectonic polygon. Most of the expedition will pass along the advanced ranges of the Tien Shan.
Abstract and theme of excursions
The modern mountain system of the Tien Shan is an active intra-continental mountain belt in Central Asia [Delvaux et al., 2001] which is formed between the Tarim and Kazakhstan platforms from the Miocene period [Schulz, 1948; Chediya, 1986; Abdrakhmatov et al., 1996]. Currently, it is also characterized by a high degree of seismic and tectonic activity.
The Tien Shan activity increased substantially in the Tertiary period due to the collision of the Indian and Euroasian tectonic plates. Compression deformation and destruction of individual segments of the system began in the Late Oligocene or Middle Miocene and their activity increased especially in the Tertiary Quaternary period (Tapponnier and Molnar, 1979; Cobbold and Davy, 1988], [Chediya, 1986; Sadybakasov, 1991; Hendrix et al., 1994; Cobbold et al., 1993, 1996], [Bullen, 1999], [Hendrix et al., 1994; Allen et al, 1991; Avouac at al., 1993].
Preliminary studies of paleostructures showed that Paleogene-Neogene deformations were the result of compressive field pressures with the main horizontal compression axis, N-S directions. The current stress field is still characterized by contraction of the N-S direction. The average speed of N-S compression of the Tien Shan is today 20 mm / year, based on GPS measurements in Kazakhstan, Kyrgyzstan. [Zubovich et al, 2010].
The figure shows the map of active faults of the Kyrgyz Tien Shan, which was compiled by Abdrakhmatov et al. [Chediya, 1986; Cobbold et al., 1996] , [Gushchenko, 1979]. [Abdrakhmatov et al., 1996] and China [Michel et al., 1997].
Program and route of the expedition:
The research expedition consists of three regional parts and covers the central part of the northern Tien Shan. The route of the expedition (shown in the figure) is constructed in such a way that during consecutive excursions, to demonstrate examples of neotectonic and modern structures, as well as modern tectonic deformations of ancient archaeological structures and structures, as well as paleoseismic formations.
In the course of excursions we will stop at typical and representative places, where we will conduct a detailed description of the geological object.
This expedition program includes four workshops.
During the first excursion, we will conduct a study of deformations between the Chui basin and the Kyrgyz ridge.
During the second excursion, we will conduct a study of the Suusamyr intermontane depression, its main structural deformations and artifacts after the 1992 earthquake.
During the third excursion, we will conduct a study of the relationship between the neotectonic structure of the Issyk-Kul basin, the regional fault system, and historical and morphostructural artifacts that arose after earthquakes.