The new GPS data can map crustal strain rates over large areas with a useful degree of precision. Stable strain measurement results open the door for improved estimates of earthquake occurrence. The Kostrov’s formula...The new GPS data can map crustal strain rates over large areas with a useful degree of precision. Stable strain measurement results open the door for improved estimates of earthquake occurrence. The Kostrov’s formula (1974) translates the smoothed strain rates in North China into geodetic moment rates. In North China, the ratio of seismic moment released to moment accumulated from GPS measurement is 60.6% in NS direction, 68.9% in EW direction, and 104.1% in NE shear direction. The near unit ratio points to the reliability of GPS measurements there. The combination of historical seismicity and GPS measurement offers a powerful attack on earthquake hazard.展开更多
The authors analyze co_seismic displacement field derived from the Global Position System (GPS) observations collected before and after the 2001 Kokoxili earthquake, western China. Using the co_seismic displacement da...The authors analyze co_seismic displacement field derived from the Global Position System (GPS) observations collected before and after the 2001 Kokoxili earthquake, western China. Using the co_seismic displacement data, and constrained with surface rupture data, they invert co_seismic slip distribution along the seismic fault. Their result shows that the earthquake ruptured the upper crust down to a depth of 13.1～22km (at 70% certainty), with its optimal estimate at 16.5km. A 2～3m left_lateral strike slip is resolved between the Sun Lake segment and the west end of the main rupture zone, although surface rupture has not been observed there. The surface rupture of this earthquake is ended at the Sun Lake to the west, but left_lateral slip of 1.5～2.0m seems to exist beyond the east end of surface rupture observed from field geology. Seismic moment release estimated using GPS and surface rupture measurement is 6.0×10 20 N·m, which is in good agreement with the result obtained from seismic wave inversion.展开更多
文摘The new GPS data can map crustal strain rates over large areas with a useful degree of precision. Stable strain measurement results open the door for improved estimates of earthquake occurrence. The Kostrov’s formula (1974) translates the smoothed strain rates in North China into geodetic moment rates. In North China, the ratio of seismic moment released to moment accumulated from GPS measurement is 60.6% in NS direction, 68.9% in EW direction, and 104.1% in NE shear direction. The near unit ratio points to the reliability of GPS measurements there. The combination of historical seismicity and GPS measurement offers a powerful attack on earthquake hazard.
文摘The authors analyze co_seismic displacement field derived from the Global Position System (GPS) observations collected before and after the 2001 Kokoxili earthquake, western China. Using the co_seismic displacement data, and constrained with surface rupture data, they invert co_seismic slip distribution along the seismic fault. Their result shows that the earthquake ruptured the upper crust down to a depth of 13.1～22km (at 70% certainty), with its optimal estimate at 16.5km. A 2～3m left_lateral strike slip is resolved between the Sun Lake segment and the west end of the main rupture zone, although surface rupture has not been observed there. The surface rupture of this earthquake is ended at the Sun Lake to the west, but left_lateral slip of 1.5～2.0m seems to exist beyond the east end of surface rupture observed from field geology. Seismic moment release estimated using GPS and surface rupture measurement is 6.0×10 20 N·m, which is in good agreement with the result obtained from seismic wave inversion.
