Comparison between the NEIC broadband radiated energy catalogue and the Harvard CMT catalogue provides information about apparent stress. In spite of its significant uncertainties and limited reliability, the clues ob...Comparison between the NEIC broadband radiated energy catalogue and the Harvard CMT catalogue provides information about apparent stress. In spite of its significant uncertainties and limited reliability, the clues obtained from this comparison seem interesting in the physics of earthquakes. Scaling of apparent stress provides information about the dynamic friction along an earthquake fault. Relation between reduced energy and seismic moment implies that for strike-slip earthquakes, velocity-dependent friction plays a predominant role, while for non-strike-slip earthquakes, slip-dependent friction is predominant. It is also found that strike-slip events with extremely low apparent stress tend to occur “in single”, which is applied to the prediction of the seismic tendency following the 2001 Qinghai-Xizang (Tibet) border M W7.8 earthquake.展开更多
The May 12, 2008, Ms8.0 Wenchuan earthquake was the outcome of a recent movement of an active intra-continental thrust fault zone. The seismogenic fault of this earthquake underwent oblique-slip faulting along the cen...The May 12, 2008, Ms8.0 Wenchuan earthquake was the outcome of a recent movement of an active intra-continental thrust fault zone. The seismogenic fault of this earthquake underwent oblique-slip faulting along the central fault and pure thrust faulting along the range-front fault of the Longmenshan fault zone. The former had a steep dip and large vertical displacement, and the latter had a gentle dip and little vertical displacement. The fault zone consisted of compressive double fault ramps rup turing with right-lateral strike-slip components resulting from strain partitioning of a deep oblique slip fault in the brittle zone of the upper crust. The kinematic pattern and rupture mechanisms are complex for the seismogenic fault, as indicated by the geometric pattern of its surface ruptures, the coseismic displacement distribution and focal mechanisms of the main shock and aftershocks. As a tear fault, the NW-trending, left-lateral, strike-slip Xiaoyudong fault zone has accommodated NE-trending displacements with different shortening amounts. However, because of intense compression on the southwestern segment of the seismogenic fault, the left-lateral, strike-slip Xiaoyudong fault also carries a clear compression component. Normal faulting with a strike-slip component controls the formation of a fault-trough along the central fault, which is characterized by thrusting with a strike-slip component and strike-slip with thrusting. The fault-troughs are the product of the interaction of slip and grav ity on the seismogenic fault under specific geological and geomorphic conditions. Gravitational force exaggerated the vertical component of fault displacement, which by no means represents the actual maximum vertical displacement of the seismogenic fault.展开更多
文摘Comparison between the NEIC broadband radiated energy catalogue and the Harvard CMT catalogue provides information about apparent stress. In spite of its significant uncertainties and limited reliability, the clues obtained from this comparison seem interesting in the physics of earthquakes. Scaling of apparent stress provides information about the dynamic friction along an earthquake fault. Relation between reduced energy and seismic moment implies that for strike-slip earthquakes, velocity-dependent friction plays a predominant role, while for non-strike-slip earthquakes, slip-dependent friction is predominant. It is also found that strike-slip events with extremely low apparent stress tend to occur “in single”, which is applied to the prediction of the seismic tendency following the 2001 Qinghai-Xizang (Tibet) border M W7.8 earthquake.
基金supported by Wenchuan Fault Scientific Drilling Program
文摘The May 12, 2008, Ms8.0 Wenchuan earthquake was the outcome of a recent movement of an active intra-continental thrust fault zone. The seismogenic fault of this earthquake underwent oblique-slip faulting along the central fault and pure thrust faulting along the range-front fault of the Longmenshan fault zone. The former had a steep dip and large vertical displacement, and the latter had a gentle dip and little vertical displacement. The fault zone consisted of compressive double fault ramps rup turing with right-lateral strike-slip components resulting from strain partitioning of a deep oblique slip fault in the brittle zone of the upper crust. The kinematic pattern and rupture mechanisms are complex for the seismogenic fault, as indicated by the geometric pattern of its surface ruptures, the coseismic displacement distribution and focal mechanisms of the main shock and aftershocks. As a tear fault, the NW-trending, left-lateral, strike-slip Xiaoyudong fault zone has accommodated NE-trending displacements with different shortening amounts. However, because of intense compression on the southwestern segment of the seismogenic fault, the left-lateral, strike-slip Xiaoyudong fault also carries a clear compression component. Normal faulting with a strike-slip component controls the formation of a fault-trough along the central fault, which is characterized by thrusting with a strike-slip component and strike-slip with thrusting. The fault-troughs are the product of the interaction of slip and grav ity on the seismogenic fault under specific geological and geomorphic conditions. Gravitational force exaggerated the vertical component of fault displacement, which by no means represents the actual maximum vertical displacement of the seismogenic fault.
