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 Tian 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 Tian 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 Tian Shan.
Abstract and theme of excursions
The modern mountain system of the Tian 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 Tian 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.
Day 1. Arrival in Bishkek.
Hotel accommodation. Briefing. Presentation of the expedition program.
Day 2. Bishkek – Chon-Aryk – Baitik.
The beginning of the first field excursion on the topic – Neotectonics, modern structures and seismic deformations between the Kyrgyz ridge and the Chui basin. After breakfast, the first part of the excursion begins with the study of the tectonic contact and structure between the Chui basin and the Kyrgyz mountain range. Stop 1 (Place of observation 1). Foothills of the Kyrgyz ridge, Issyk-Ata fault of the Adyr zone. Chon-Aryk, south of the outskirts of Bishkek. Stop 2. Bajtik’s Quaternary depression (Chon-Tash, southern outskirts of Bishkek). During the tour, lunch with hot tea and coffee. In the evening return to the hotel. The first seminar in the conference hall of the hotel. Dinner at the national restaurant. Theme of the seminar.
Day 3. Bishkek – Ala-Archa – Chon-Kurchak.
In the morning after breakfast, excursion to the granite formations of the Kyrgyz ridge. Stop 3. Seismic station Ala-Archa (the valley of the Ala-Archa River, 25 km south of Bishkek). Place of observation 4. Formation of mudflows (the upper part of the Ala-Archa River valley, 35 km south of Bishkek). Stop 5. Paleoseismic dislocations in Chon-Kurchak canyon (place Tatyr, 25 km south of Bishkek. Stop 6. The impact plane of the Chonkurchak seismic shock (in the Chon-Kurchak area, 28 km south of Bishkek). In the evening return to the hotel. Dinner at the national restaurant. Preparation for the field part of the expedition.
Day 4. Bishkek – Sosnovka – Tuya-Ashuu Pass – Suusamyr Valley.
Field camp in the valley of the river Kokemeren. After breakfast we will start the field expedition. The whole route is about 160 km. The way from Bishkek to the Suusamyr valley lies through the Kyrgyz ridge. The road passes through a tunnel under the Tuya-Ashu pass (3300 m). The field base camp will be installed in the picturesque valley of the Kokemeren River. The expedition goes along the southern end of the Chui basin, where a system of active faults is formed. Stop 7. We will be able to observe signs of a system of active faults in the western part of the Chui basin (South of the village of Sosnovka, 60 km southeast of Bishkek). Arrival to the base camp. Overnight in tents.
Day 5. Study of characteristic seismotectonic structures in the Suusamyr Basin.
The beginning of the second field excursion on the theme – Seismotectonics of the Suusamyr depression and earthquake (Ms-7.3 1992). After breakfast in the field camp, we will tour the Suusamyr valley. Stop 8. Active faults of the Suusamyr depression (Tuya-Ashu pass, 50 km from Bishkek). Stop 9. Change in the pattern of the hydroset due to the impact of neotectonics (Tokoilu river valley, 20 km WNW Suusamyr). In the evening, the second seminar on the theme. Overnight in a field tent camp in Kokemeren Valley.
Day 6. Excursions and practical classes. Study of structural-tectonic features of the Suusamyr valley.
Stop 10. The eastern tectonic ledge that arose as a result of the Suusamyr earthquake (162 km of the Bishkek-Osh road). Stop 11. Morphostructure changes in the relief after the Suusamyr earthquake. (166 km of the Bishkek-Osh road). Stop 12. Changed drawing of the hydrological network in the valley of the Chon-Corumda river due to modern active tectonics. In the evening, return to the camp. Overnight in a field tent camp.
Day 7. Transfer from Suusamyr valley – along the valley of the Western Karakol river to the Kochkor village.
In the morning after breakfast continue the tour. On the way to Kochkor, the study of the Mesozoic-Cenozoic complex (MZ-KZ) sediments. Stop 13. Study of modern river terraces in the valley of the Western Karakol river. On the way, lunch with hot tea and coffee. Further arrival is Kochkor. In Kochkor visit the original felt production and the museum of felt products. Overnight at the guest house.
Day 8. Transfer to the Issyk-Kul Basin.
The third field excursion on the topic – Neotectonic and modern structures, paleoseismic and historical deformations in the Issyk-Kul basin and its environs. In the morning after breakfast at the guest house, the expedition’s route continues to the high-mountain basin of Issyk-Kul Lake. On the way excursion. Stop 14. The Boz-Barmak modern anticline, as the reason for the deviation of the Chu River, from its confluence into the Issyk-Kul Lake. Stop 15. Seismic systems in the tract of Ordekuchar. Lake Kara-Kol (the Kyrgyz “Dead Sea”). Arrival in the small town Kaji-Sai. Accommodation in a hotel on the shore of a lake. In the evening, the third seminar on the topic.
Day 9. Study of geological structures of the southern part of the Issyk-Kul depression.
After breakfast at the hotel, continue the tour. Ascent to the peak in Kyzyl-Choku. Stop 16. Panorama of Issyk-Kul. Overview of neotectonic structures in the southeastern part of the Issyk-Kul basin. Return to the hotel.
Day 10. Transfer to the Djety-Oguz gorge.
After breakfast at the hotel, the route continues in the Djety-Oguz gorge. On the way acquaintance with the tectonic structures of the southern part of the Issyk-Kul depression. Stop 17. Duvana. Tectonic structures of the Kokonadyr-Tegerek ridge and tectonic depression of Alabash-Konurleng. Stop 18. The system of Tosor faults. Geological monument of Shiga. Stop 19. Geological monument Djety-Oguz (“Seven buffaloes”). Study of the full Meso-Cenozoic (MZ-KZ) section on the northern slope of the Terskey Ala-Too Range. Overnight in the yurt camp in the Djety-Oguz gorge.
Day 11. Transfer to the Karakol city.
After breakfast, a short tour of the Djety-Oguz gorge. Further, moving to the Karakol city. On the way, study the tectonic structures of the southern part of the Issyk-Kul depression. Stop 20. Bir-Bash anticline. Karakol seismics. Arrival in Kara-Kol city. Lunch at the restaurant. Visit to the memorial complex of the great Russian traveler, the discoverer N. Przhevalskii. Accommodation in hotel of Karakol. In the evening, the fourth seminar in the conference hall of the hotel. Theme of the seminar.
Day 12. Kara-Kol – Cholpon-Ata
After breakfast at the hotel, transfer to the Cholpon-Ata city. The route runs along the eastern shore of the lake. Stop 21. Study of the geological section in the Tup river valley. Study of geological outcrops of lake, alluvial, proluvial Mesozoic-Cenozoic (MZ-KZ) rock complexes. On the way, study seismotectonic structures and artifacts. Stop 22. Study of seismic destruction of the medieval fortress Kamenka that occurred in the beginning of the XII century. Stop 23. Seismic deformations in the valley of the Chon-Aksuu river, caused by the Kebin earthquake of 1991 (M> 8, I = X-XI). Further along the way, study of magmatic complexes in the area of the “Prishib” site. Arrival in Cholpon-Ata Overnight at hotel in Cholpon-Ata.
Day 13. Geological excursion in the vicinity of Cholpon-Ata.
After breakfast at the hotel, continue the tour. Stop 24. Excursion to the rock paintings near the town of Cholpon-Ata. Stop 25. Signs of the influence of quaternary tectonic activity on the interior of the Issyk-Kul basin. Long-term seismic activity of the South Aktikinsky fault. After lunch, excursion by boat on Issyk-Kul lake. Overnight at the hotel.
Day 14. Transfer to Kok-Moynok canyons – Boom Gorge – Historical and Architectural Complex of Burana – Bishkek.
After breakfast in the hotel, the expedition continues on its way to Bishkek. On the way acquaintance with seismic and geological structures. Stop 26. Canyons of Kok-Moynok. The seismogenic boundary of disturbance in the layers of lake deposits of Toguz-Bulak, Kok-Moinok depression is the paleo-gulf of Issyk-Kul Lake in the Middle Pleistocene. Stop 27. Small tectonic depression in the Cenozoic basalts in the Boom gorge. Stop 28. Gil-Arykskaya depression – epicentral zone of the Chu-Keminsky earthquake of 1938 (M> 6.5, I = VIII). Stop 29. Visit to the historical museum of Buran, a monument of the Karakhanid empire, destroyed by a strong earthquake in 1475. Arrival in Bishkek. Accommodation in a hotel in Bishkek.