The Talas-Fergana Fault, the largest strike-slip structure in Central Asia, forms an obliquely orien- ted boundary between the northeastern and southwestern parts of the Tianshan mountain belt. The fault under- went a...The Talas-Fergana Fault, the largest strike-slip structure in Central Asia, forms an obliquely orien- ted boundary between the northeastern and southwestern parts of the Tianshan mountain belt. The fault under- went active right-lateral strike-slip during the Paleozoic, with right-lateral movements being rejuvenated in the Late Cenozoic. Tectonic movements along the intracontinental strike-slip faults contribute to absorb part of the regional crustal shortening linked to the India-Eurasia collision; knowledge of strike-slip motions along the Ta- las-Fergana Fault are necessary for a complete assessment of the active deformation of the Tianshan orogen. To improve our understanding of the intracontinental deformation of the Tianshan mountain belt and the occurrence of strong earthquakes along the whole length of the Talas-Fergana Fault, we identify features of relief arising during strong paleoearthquakes along the Talas-Fergana Fault, fault segmentation, the length of seismogenic ruptures, and the energy and age of ancient catastrophes. We show that during neotectonic time the fault devel- oped as a dextral strike-slip fault, with possible dextral displacements spreading to secondary fault planes north of the main fault trace. We determine rates of Holocene and Late Pleistocene dextral movements, and our radi- ocarbon dating indicates tens of strong earthquakes occurring along the fault zone during and interval of 15800 years. The reoccurrence of strong earthquakes along the Talas-Fergana Fault zone during the second half of the Holocene is about 300 years. The next strong earthquake along the fault will most probably occur along its southeastern chain during the next several decades. Seismotectonic deformation parameters indicate that M〉7 earthquakes with oscillation intensity I〉IX have occurred.展开更多
The emergence of Zhang Heng's seismoscope has a profound historical background. This paper intends to explore the formation and material basis of Zhang Heng's scientific thought. It appears that the simple int...The emergence of Zhang Heng's seismoscope has a profound historical background. This paper intends to explore the formation and material basis of Zhang Heng's scientific thought. It appears that the simple intention of "observing visions and distinguishing good fortune or misfortune"was his motivation to develop the seismoscope. Tracing its historical background,the authors proposed in this paper that the development of this seismoscope started around 128 A. D., and based on perceptual knowledge, two ideas about earthquakes came into being,i. e.,earthquake location could be judged according to the instrument shaking direction, and the earthquake and earth split were essentially different. In the instrument manufacture,Zhang Heng advocated a principle of "making utensils to imitate cosmos". By this principle,the following three problems were readily solved: the seismoscope imitated the response of the suspension system to earthquakes( i. e. natural seismoscope). Technically,the trigger mechanism of the latch was used for reference,and it recorded the physical evidence of earthquake occurrence by an ingenious way of a ball dropping from a dragon's mouth. The solution of these three key problems lead to the emergence of the seismoscope in 132 A. D. and the successful detection of an earthquake in 134 A. D. His invention deepened humanity's knowledge of natural laws, and promoted the development of science and technology in that time and later.展开更多
基金supported by the NATO Science Partnership for Peace and Security Program(SfPSP 983142)the International Science and Technology Center(KR-2011)the Russian Foundation of Basic Research(RFBR-13-05-91168-GFEN_a)
文摘The Talas-Fergana Fault, the largest strike-slip structure in Central Asia, forms an obliquely orien- ted boundary between the northeastern and southwestern parts of the Tianshan mountain belt. The fault under- went active right-lateral strike-slip during the Paleozoic, with right-lateral movements being rejuvenated in the Late Cenozoic. Tectonic movements along the intracontinental strike-slip faults contribute to absorb part of the regional crustal shortening linked to the India-Eurasia collision; knowledge of strike-slip motions along the Ta- las-Fergana Fault are necessary for a complete assessment of the active deformation of the Tianshan orogen. To improve our understanding of the intracontinental deformation of the Tianshan mountain belt and the occurrence of strong earthquakes along the whole length of the Talas-Fergana Fault, we identify features of relief arising during strong paleoearthquakes along the Talas-Fergana Fault, fault segmentation, the length of seismogenic ruptures, and the energy and age of ancient catastrophes. We show that during neotectonic time the fault devel- oped as a dextral strike-slip fault, with possible dextral displacements spreading to secondary fault planes north of the main fault trace. We determine rates of Holocene and Late Pleistocene dextral movements, and our radi- ocarbon dating indicates tens of strong earthquakes occurring along the fault zone during and interval of 15800 years. The reoccurrence of strong earthquakes along the Talas-Fergana Fault zone during the second half of the Holocene is about 300 years. The next strong earthquake along the fault will most probably occur along its southeastern chain during the next several decades. Seismotectonic deformation parameters indicate that M〉7 earthquakes with oscillation intensity I〉IX have occurred.
基金sponsored by the National Natural Science Foundation of China(40644019)the Special Found of Scientific Research Program for "The Optimization and Design for Reconstruction Models of Seismoscope",China Earthquake Administration
文摘The emergence of Zhang Heng's seismoscope has a profound historical background. This paper intends to explore the formation and material basis of Zhang Heng's scientific thought. It appears that the simple intention of "observing visions and distinguishing good fortune or misfortune"was his motivation to develop the seismoscope. Tracing its historical background,the authors proposed in this paper that the development of this seismoscope started around 128 A. D., and based on perceptual knowledge, two ideas about earthquakes came into being,i. e.,earthquake location could be judged according to the instrument shaking direction, and the earthquake and earth split were essentially different. In the instrument manufacture,Zhang Heng advocated a principle of "making utensils to imitate cosmos". By this principle,the following three problems were readily solved: the seismoscope imitated the response of the suspension system to earthquakes( i. e. natural seismoscope). Technically,the trigger mechanism of the latch was used for reference,and it recorded the physical evidence of earthquake occurrence by an ingenious way of a ball dropping from a dragon's mouth. The solution of these three key problems lead to the emergence of the seismoscope in 132 A. D. and the successful detection of an earthquake in 134 A. D. His invention deepened humanity's knowledge of natural laws, and promoted the development of science and technology in that time and later.