Intraplate earthquakes in North China - Intraplate Earthquakes - page 105

Figure 5.4 GPS site velocities in mainland China relative to stable Eurasia. Data from Zhang and
Gan ( 2008 ) . Error ellipses represent the 95% confidence level.

Figure 5.5 (a) GPS velocity (relative to stable Eurasia) and strain rates (background). (b) Predicted
long-term strain energy (background) and stress states represented in sterographic lower-hemisphere
projections. (c) Seismic strain energy released in the past 2,000 years. Modified from Liu and Yang

( 2005 ) . For color version, see Plates section.

Using the velocity boundary conditions extrapolated from the GPS data, Liu and Yang
( 2005 ) developed a 3D finite element model to calculate the long-term distribution of
strain rate and strain energy (the product of scalar strain rate and stress) in North China
( Figure 5.5b ) . The spatial pattern of strain energy is comparable with seismic moment
release in the past 2,000 years, estimated using the Chinese historic catalog ( Figure 5.5c ) .