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Observation network


Global Positioning System Observation Network

Global Positions System (GPS) was developed and used by the U. S. Department of Defense in1973. It is composed of a total of 24 satellites in 6 orbital planes, each of which has 4 satellites at inclination angle of 55 degree, revolving the earth every 12 hours at the height of 20, 200 Km from the surface of the earth. Each satellite sends out carrier waves of two different frequencies at L1 (1575.42 MHz) and L2 (1227.60 MHz). It provides users of GPS receiver information regarding real time location and time in 24 hours, regardless of position, region and weather. GPS can be applied in geodesy, navigation, positioning, precision timing and general measurement.

Global Positioning System Observation Network

It is recognized in the seismic academic circle as one of the ways that are most likely to succeed among the present earthquake forecast patterns to defer the occurrence of shallow major earthquake by long-term investigation as micro-changes will result from squeezed crust. For the in-depth understanding of the relationship between the crust changes and the seismic activities in Taiwan, the Central Weather Bureau (CWB) started from 1993 to set up permanent GPS observation stations, using GPS technology to continuously monitor the precise coordinates of each station, observe the horizontal displacement of such observations stations and the relative changes in between adjacent stations to understand the displacement of plates and the crush status with a view to discussing the relativity and physics of seismic activities, energy accumulation, and the energy release process. After the 921 earthquake in 2000, CWB has been expanding the GPS observation network on a yearly basis and making observation points denser for observation of higher precision in response to the inter-ministerial integration plan of 'Earthquake and Active Fault' by the National Science Council, expecting to extensively collect data of crustal activities of Taiwan for earthquake and other related researches. By 2006, CWB has set up a total of 150 GPS observation stations across Taiwan.