Strong Mediaeval Earthquake in the Chuy Basin, Kyrgyzstan A
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ISSN 00168521, Geotectonics, 2012, Vol. 46, No. 4, pp. 303–314. © Pleiades Publishing, Inc., 2012. Original Russian Text © A.M. Korjenkov, V.A. Kol’chenko, Ph.G. Rott, S.V. Abdieva, 2012, published in Geotektonika, 2012, Vol. 46, No. 4, pp. 62–74. Strong Mediaeval Earthquake in the Chuy Basin, Kyrgyzstan A. M. Korjenkova, b, V. A. Kol’chenkoc, Ph. G. Rottd, and S. V. Abdievaa a Institute of Seismology, National Academy of Sciences of Kyrgyz Republic, Asanbay microraion 52/1, Bishkek, 720060 Kyrgyzstan email: [email protected] b Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, ul. Bol’shaya Gruzinskaya 10, Moscow, 123995 Russia c Institute of History and Cultural Herritage, National Academy of Sciences of Kyrgyz Republic, pr. Chuy 265a, Bishkek, 720071 Kyrgyzstan d Philosophische Facultaet, Universitaet Bonn, Am Hof 1, Bonn, D53113 Germany Received December 16, 2010 Abstract—The data presented in this paper show that in historical time the Chuy Basin in Kyrgyzstan was repeatedly subjected to strong earthquakes, which affected the inhabitants and the economic and political sit uation at that time. The deformed buildings in the Novopokrovka site of ancient settlements situated in the central part of the basin unequivocally indicate seismic damage and subsequent abandonment of the settle ment. The earthquake happened at the end of the Karakhanid epoch (the end of the 12th century A.D.). The intensity of seismic oscillations (I = VIII–IX) at the site was reinforced by unfavorable engineering geology conditions. The source of the earthquake was probably related to displacements along the piedmont YsykAta Fault located to the south of the site. DOI: 10.1134/S0016852112040036 INTRODUCTION long walls (Novopokrovka I) and peripheral settle ments (Novopokrovka II–V) (Fig. 2). The onset of Tien Shan mountain building was related to the late Oligocene [23]. The mountain belt Recent archeological investigations were carried arose and continued to develop as a result of ongoing out in 2004 by the Novopokrovka detachment of the collision of the Indian and Eurasian lithospheric Institute of History and Cultural Inheritance, plates [38]. Mountain building can be slow and grad National Academy of Sciences of the Kyrgyz Republic ual (millimeters per year and slower) and be described with assistance of the Society of Exploration of Eur as creep; however, in the Tien Shan, instantaneous asia, Basel, Switzerland under the guidance of seismic events make the main contribution to moun V.A. Kol’chenko and Ph.G. Rott [7]. The ancient set tain building [9]. Such movements are recorded by a tlements arose in the 7th to 8th centuries. The archeo network of seismic stations. Unfortunately, instru logical site is multilayered, consisting of at least three mental seismic records have been available only during practically unrelated construction levels. As is indi the last 100 years, beginning from the Kemin earth cated by numismatic finds, the upper level (see below) quake in 1911 (M > 8), the seismogram of which was is not older than the thirties of the 11th century A.D. recorded by the seismograph installed at Potsdam. The performed special archeoseismological study To predict the date of the next strong earthquake, revealed the unusual character of the destruction of even approximately, the reoccurrence of strong seis walls in the trench located in the southeastern corner mic events, which took place along a certain active of the site. This paper is concerned with the seismic seismic fault over the last millennia, must be esti hazard of the nearest seismic active adyr (piedmont) mated. Such information can be obtained by historical YsykAta Fault and archeoseismological study of the seismology, archeoseismology, and paleoseismology. deformed buildings. The Novopokrovka site of ancient settlements is situated in the central part of the Chuy Basin at the SEISMOGEOLOGY eastern outskirts of the Bishkek urban area (Fig. 1). Its OF THE CHUY VALLEY ° ′ ′′ ° ′ ′′ coordinates are 42 52 17.7 N, 74 43 21.5 E; its The northern boundary of the region of recent height is 783 masl. mountain building in the Tien Shan extends, in partic The archeological study of this site was performed ular, along the Chuy Valley, which is tectonic in origin. by P.N. Kozhemyako in 1952–1955. Among monu Numerous earthquakes have been recorded here ments of urban culture, he described and mapped five (Fig. 3). Although most of the earthquakes are weak mediaeval settlements [6]: the core settlement with and can be recorded only using sensitive seismic 303 304 KORJENKOV et al. 75° E Korday Ch 43° 2 u 3 ty N Yrgay 9 GCC Mramornoe 1 8 5 Kordoy 4 AlaArcha 7 Res. Leninskoe Bishkek Alamudun Kant 6 Novopavlovka Lebedinovka Ivanovka GCC huy Ch. Greater C Novopokrovka Shopokov ChongAryk Bishkek KyzylToo Arashan Yur’evka TashDobo Fig. 1. Location of Novopokrovka Settlement in the cen tral part of the Chuy region, Kyrgyzstan, after [11]. n u s d u r u a o h m N c devices, rather strong shocks, perceptible to inhabit a r l A A ants of the area, are known. Rare earthquakes gave rise ta a A to significant destruction and even casualties. Histori l A k y s cal records show that such earthquakes have recurred Y many times. Information on strong earthquakes in the more Fig. 2. Archeological sites of mediaeval settlements in the remote past has been obtained from historical chroni Chuy Valley, after Kozhemyako [6]: 1, Klyuchevsky; cles and from the results of paleoseismological studies. 2, Grozd; 3, Chumysh I; 4, Krasnaya Rechka; 5, Novopokrovka I; 6, Novopokrovka II; 7, Novopokrovka III; The socalled VIII–IX M 1475 Balasagun earthquake 8, Novopokrovka IV; 9, Novopokrovka V. GCC, Great (1475, I = VIII–IX) destroyed the capital of the Kar Chuy Channel. akhanid state—the Balasaguncity and its vicinity (the Burana archeological site eight kilometers south from the presentday town of Tokmok in the eastern part of the basin and on the northern slope of the Kyr Chuy Valley). According to [27], its epicenter was gyz Range. The seismic dislocations in the southern located on the northern slope of the Kyrgyz Range in framework of the Chuy Basin are subdivided into the basin of the Shamshy River. zones [1, 2, 20–22, 27], which in turn consist of sev Fragmentary information on the 1770 earthquake eral deformations clusters related to faults or tectonic near the presentday Belovodskoe Settlement (a large blocks bounded by faults. lake has been filled here) shows that its epicenter The longstanding investigations of the neotecton approximately coincided with the 1885 earthquake. A catastrophic earthquake took place at Merke Settle ics of Central Asia, and the Tien Shan in particular, ment (1865), at Tokmok (1867), and in the Chuy Val and the correlation of their results with instrumental ley (1873). Information on the catastrophic earth data on seismicity has lain the basis for the concept of quake at the Belovodskoe Settlement was received on local and regional seismogenic boundary fault zones August 3, 1885. The scientific study of strong earth and lineaments crosscutting the main structural ele quakes in the Chuy Basin and its mountain framework ments. As a rule, the main outburst of seismic activity began at this time. is accounted for by splitting and en echelon arranged Besides historical earthquakes, the trails of ancient faults. The Shamshy segment of the South Chuy seis seismic catastrophes are recorded in seismic deforma mogenerating zone in the Northern Tien Shan is an tions. Such trails are mostly localized in the southern example. GEOTECTONICS Vol. 46 No. 4 2012 STRONG MEDIAEVAL EARTHQUAKE IN THE CHUY BASIN, KYRGYZSTAN 305 73° 74° 75° 76° E 43°30′ 43°30′ N KAZAKHSTAN 5.3, 25.12.1910 5.4, 08.11.1886 43°00′ 5.4, 18.01.1926 43°00′ 6.0, 01.01. 1770 5.0, 14.12.1948 5.8, 18.07.1889 6.4, 22.03.1865 6.4, 29.08.1868 6.0, 04.11.1893 4.8, 31.01.1888 Bishkek 6.9, 20.06.1938 6.9, 02.08.1885 5.4, 16.09.1888 5.2, 11.12.1935 42°30′ 5.2, 22.03.1993 6.4 01.01.1475 42°30′ KYRGYZSTAN 4.9, 27.09.1934 4.8, 19.08.1992 4.9, 02.07.1974 5.2, 19.08.1992 6.7, 19.08.1992 6.2, 19.08.1992 5.4, 19.08.1992 4.7, 15.12.1928 6.5, 19.08.1992 7.5, 19.08.1992 5.2, 24.06.1946 42°00′ 42°00′ 73° 74° 75° 76° Fig. 3. Strong earthquakes in the Chuy Basin, after the data of Institute of Seismology, National Academy of Sciences, Kyrgyz Republic. Earthquakes differing in intensity are noted by circles differing in size. The larger the circle size, the greater the amount of seismic energy released. Numerals in circles: the first value is the magnitude; numerals following the commas represent the day, month, and year of the seismic event. The figure was kindly placed at our disposal by A.V. Berezina. The South Chuy seismogenic zone is recognized shy–Tyundyuk Fault, and the Kemin Zone along the within the North Tien Shan seismic belt [4, 15] at the Kemin faults [5]. The aforementioned major seis boundary between the Chuy Basin and the Kyrgyz mogenic faults and the secondorder faults are respon Range. This zone combines the three most important sible for strong historical and ancient earthquakes; seismogenic boundary faults (Fig. 4). In the west, this their trails are marked by seismic deformations. is the Chonkurchak Fault, which controlled the epi centers of the Belovodsky catastrophic earthquakes SEISMIC DEFORMATIONS ALONG 1865 and 1885 (ML = 6.4 and 6.9, respectively).