On the basis of the newly released International Terrestrial Reference Frame(ITRF2008) by the International Earth Rotation Service(IERS),a new global plate model ITRF2008 plate for the major plates is established.This ITRF2008-derived model is analyzed in comparison with NNR-NUVEL1A model,which is mainly based on geological and geophysical data.The Eurasia and Pacific plates display obvious differences in terms of the velocity fields derived from the two plate motion models.Plate acceleration is also introduced to characterize the differences of the two velocity fields which obtained from ITRF2008-plate and NNR-NUVEL1A models for major individual plates.The results show that the Africa,South America and Eurasia plates are undergoing acceleration,while the North America and Australia plates are in the state of deceleration motion.
Zhu ZeMeng GuojieSu XiaoningWu JicangLi Jean Xiaojing
After M_W 7.8 Nepal earthquake occurred, the rearrangement of stresses in the crust commonly leads to subsequent damaging earthquakes. We present the calculations of the coseismic stress changes that resulted from the 25 th April event using models of regional faults designed according to south Tibet-Nepal structure, and show that some indicative significant stress increases. We calculate static stress changes caused by the displacement of a fault on which dislocations happen and an earthquake occurs. A M_W 7.3 earthquake broke on 12 May at a distance of * 130 km SEE of the M_W 7.8 earthquake, whose focus roughly located on high Coulomb stress change(CSC) site. Aftershocks(first 15 days after the mainshock)are associated with stress increase zone caused by the main rupture. We set receiver faults with specified strikes, dips,and rakes, on which the stresses imparted by the source fault are resolved. Four group normal faults to the north of the Nepal earthquake seismogenic fault were set as receiver faults and variant results followed. We provide a discussion on Coulomb stress transfer for the seismogenic fault, which is useful to identify potential future rupture zones.
