Problems of Engineering Seismology: article

ADYR FAULTS ARE GENERATORS OF THE STRONG EARTHQUAKES IN THE ISSYK-KUL LAKE DEPRESSION(ON EXAMPLE OF KULTOR FAULT ZONE)
A.M. KORZHENKOV1
A.A. STRELNIKOV1
E.V. DEEV2,3
L.A. KORZHENKOVA1
J. LIU4
J.V. MAZEIKA5
E.A. ROGOZHIN1
S.N. RODINA1
I.V. TUROVA2,3
M.T. USMANOVA6
A.B. FORTUNA7
1 Schmidt Institute of Physics of the Earth, Russian Academy of Sciences
2 Trofimuk Institute of Oil and Gas Geology and Geophysics SB RAS
3 Novosibirsk State University
4 Institute of Geology, China Earthquake Administration
5 State Research Institute «Center of Nature Research»
6 Mavlyanov Institute of Seismology, AS of Republic of Uzbekistan
7 Institute of Seismology, NAS of Kyrgyz Republic
Journal: Problems of Engineering Seismology
Tome: 47
Number: 2
Year: 2020
Pages: 19-44
UDK: 550.34.063 + 550.347.29 + 550.347.62
DOI: 10.21455/VIS2020.2-2
Аnnotation file
Bibliographic list
Keywords: adyrs, fault scarps, strong earthquakes, trenching, paleoseismology, archeoseismology, Kultor fault, Issyk-Kul depression, Kungey Ala-Too Range, seismic hazard
Аnnotation: We have studied eastern end of the Kultor adyr (foothill) fault in northern Issyk-Kul Lake region. Morphologically the fault zone is a staircase of seismic fault scarps formed by movements along few adjacent ruptures gently tilted under the adyrs (northward). Numerous saka-wusun, turkic and karakhanid archeological monuments got onto slope parts of the fault scarps and were damaged and destroyed. Logging of paleoseismological trenches excavated across southernmost and youngest fault scarps allows us to determine minimal age, reoccurrence interval and energy of strong historical earthquakes. Strong earthquakes along studied part of the adyr fault occurred during periods: 60-170 AD; 530-620 AD; 1160-1250 AD; 1410-1460 AD. Time intervals among dates (strong earthquakes reoccurrence along the fault) is 200-600 years. Obtained parameters of the fault scarps were used for calculation of magnitudes of the historical seismic events: М = 7.2 and М = 6.9 according to heights of studied fault scarps. These magnitudes can produce seismic oscillations in the earth surface of I0 ≥ IX according to MSK-64 scale. Our earlier supposition on involvement into uplift southern parts of the Issyk-Kul depression has got confirmation. Lateral longitudinal increasing of adyrs square takes place during strong earthquakes. These conclusions are important at consideration of new seismic hazard assessment of the northern Issyk-Kul Lake region, the most populated part of the Issyk-Kul Oblast’ of Kyrgyz Republic, as well as for other regions of the Earth Globe developing in regime of the postplatform orogens.