Thesis
GPS Study for Resolving The Stability of Borobudur Temple Site
The maintenance of the worlds important cultural monuments is a complex task embracing many disciplines. One important aspect of individual management plans is the stability of the monument. Borobudur, in Central Java, uncovered in a state of dilapidation in the early nineteenth century and finally restored in the second half of the twentieth century was restored using internal beams and injection technology with the view of providing a stable foundation for the foreseeable future.
Of necessity, any measurement of change involves at least two observation epochs. In general the precision is tied to the number of epochs and the span between the epochs. Since this study has had only observation epochs, the results can only be described as preliminary or indicative. Never the less, there are a number of clear trends that are apparent. The first important points is that GPS is able to deliver precisions that are near 1 mm in the horizontal and 2-3 mm in the vertical relative to a regional fiducial control network. This is comparable to terrestrial surveying techniques. Moreover, it is accomplished in 10 to 14 days compared to many weeks fo levelling.
The second is that the level of redundancy and spatial coherence's very high enabling errors and outliers to be readily detected. This was used extensively as part of the quality assurance program adopted in this study.
The third point is that no alarming deformation of the temple has been detected. At this stage of the study, the 95% confidence levels are quite large due mainly to only 2 epoch being observed but also in part to the way the models, escially the GLOBK model, has been implemented due to the limited number of epochs and thelimited time span. It is expected that the model of tectonic motion which connects one epoch to the next will improve dramatically with a third epoch, and thus will significantly improve the precision of the observation stations on the temple at the stupa level and on the buttress level. However, there is already clear evidence that some of the buttress level stations are in an unstable environment compared with stupa level stations and this is primarily due to their location.
In the past, classical surveying separated the vertical and horizontal components. This separation often resulted in different stations having different information. Moreover, one technique was not generally able to add constraints to the other. Today's surveyors and Cultural Heritage managers use the Global Positioning System which is aable to provide precise and reliable information for both the horizontal and vertical components, thereby unifying the networks and maximizing individual streghts, especially the deep marks associated with precise leveling., which are significantly less prone to local erratic movement than surface marks.
Perpustakaan Balai Konservasi Borobudur