HR: 15:10h
AN: T53D-07 [Abstracts]
TI: A Geodynamic Study of Active Crustal Deformation and Earthquakes in North China
AU: Yang, Y
EM: yangyo@missouri.edu
AF: University of Missouri, 101 Geology Building, Columbia, MO 65211
United States
AU: * Liu, M
EM: lium@missouri.edu
AF: University of Missouri, 101 Geology Building, Columbia, MO 65211
United States
AB:
North China is part of the Archaean Sino-Korean craton, yet today it is a region of intense crustal deformation and
earthquakes, including 21 M >=7.0 events since 512 AD. More than half of the large events occurred within the Fen-Wei rift
system surrounding the stable Ordos plateau; the largest events (M >=7.3) show a sequential southward migration along the
rift. However, since 1695 the Fen-Wei rift has became seismically dormant, while seismicity seems having shifted eastward to
the North China plain, marked by the 1996 Tangshan earthquake (M=7.8). We have developed a 3D viscoelastic geodynamic model
to study the cause of seismicity and its spatial-temporal pattern in North China. Constrained by crustal kinematics from GPS
and neotectonic data, the model shows high deviatoric stress in the North China crust, resulting mainly from compression of
the expanding Tibetan Plateau and resistance from the stable Siberian block. Within North China seismicity is largely
controlled by lateral heterogeneity of lithospheric structures, which explains the concentration of seismicity in the Fen-Wei
rift. Our results show that stress triggering may have contributed to the sequential migration of large events along the
rift, and the release and migration of stress and strain energy from these large events may partially explain the intense
seismicity in the North China plain in the past 300 years. Comparing the predicted long-term spatial pattern of strain energy
with seismic energy release provides some insights of potential earthquake risks in North China.
UR: http://www.missouri.edu/~yangyo/
DE: 2753 Numerical modeling
DE: 8107 Continental neotectonics (8002)
DE: 8118 Dynamics and mechanics of faulting (8004)
DE: 8123 Dynamics: seismotectonics
DE: 8164 Stresses: crust and lithosphere
SC: Tectonophysics [T]
MN: Fall Meeting 2005