E. Topographical and Geological Monitoring Study
| (1) Project for an active fault monitoring system |
Among the means and practices employed in identification and monitoring fault locations and fault
activities geodetic surveying proved to be one effective method that is capable of achieving high
precision within relatively short time span.
The present project will see completion of a near-fault (<1km at near fault area) GPS and precision
surveying and monitoring net. The project for the first year will perform monitoring on activities of
the Hsincheng, Hsinhua, Houchia, Meishan, Changhua and Chelungpu faults
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| (2) Active fault and ground subsidence monitoring |
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Through repeated monitoring data collected by the "Taiwan GPS Survey Net" for the past several years,
the behavior of crustal movement and strain accumulation has been unfolded. An attempt was made using
2-D numerical model in explaining the abnormal turn of vector field of speed and its discontinuity,
and elucidated the effects from a discontinuity (major fault) as well as from the high of the basement.
Up to the end of fiscal year 1001, besides the 99 new surveying control points and the 104 new GPS
reference points installed during execution of the Project "Seismic geological surveying and
establishing a data bank on active faults, Monitoring System for Active Faults Project", a total of
close to 300 GPS monitoring points had been installed in western and north eastern Taiwan, these
points are inclusive of the Class 1 Satellite control points of the Ministry of the Interiors, and
the full-time tracking stations and monitoring points managed by Academia Sinica, the Chengkung
University, and the Chiaotung University.
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| (3) Monitoring Project on Active Faults in Southeast Taiwan and the Hengchun Peninsula |
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The Pingtung Plains with the adjacent hills areas measures 60 km in length from north to south, and 25
km in width from east to west. In this area, 41 GPS points had been installed in the past. In order
that regional deformation data could also be obtained, the points were evenly spread, as much as
feasible, distance between points ranged from 5 to 10 km. Results from the three initial monitoring,
when viewed from the ground subsidence and crustal deformation of the Pingtung Plains point of view,
indicated 3-D spatial deformation. In other words, the entire Pingtung Plain was somewhat deforming.
The Hengchun Peninsula is the narrowest extremity of the Central Mountain Range, and also is the
southern end of the island of Taiwan. The Hengchun Fault is located in this area, it strikes in a
northwest-southeast direction from Chehcheng to the viciniity of Nanwang. Since the No. 3 Nuclear
Power Plant is situated in this area the fault had been under continuous monitoring. To monitor the
vertical deformation two main level-surveying lines, and one subordinate line were planned In addition,
along the two sides of the fault GPS monitoring points were evenly appointed for monitoring on crustal
deformation. These GPS monitoring points were also linked to precise level surveying points for
monitoring on horizontal deformation.
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| (4) Utilizing Satellite Imageries in Analyzing Coastal Changes along Western Taiwan |
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Along the stretch of seaboard surrounding the island of Taiwan development activities are becoming
intense as the years go by.Such intensive development activities caused a very conspicuous change
along theh coast. In rivers and streams of all sizes, sediment is becoming depleted, and along the
coastal areas, ground subsidence is going on at an alarming rate, these combined with the global
sea-level on the rise due to climatic changes, the coastal stretch along Taiwan showed erosion as
well as silting deposition. It is clear that an investigation on this coastal change is an urgent
issue. The use of satellite imageries on surveying the tide-line variation and further obtain a result
on the long term variation of the coast line will afford result that covers a ast area in a
comparatively short time. Employing the GPS in-situ surveying system to check and verification and
transmission error assessment, satellite imageries can be used in large-scale coastal change
monitoring.
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