Research of Marine Geophysics Processing and Official Regulation for Underwater Culture Heritage in Taiwan

In recent years, the Government of Taiwan has put considerable effort into the environment impact assessment for offshore wind potential area in Taiwan Strait, especially the research and regulation related to Underwater Cultural Heritage (UCH). From prehistorical evidence and historical record, it can be seen that Taiwan Strait is rich in archaeological character, which involves the traces of people living in 10,000 years ago (The Paleolithic Age), and the remains of human activities on the water before 100 years. Since the cultural and historical value of the material preserved under the sea, the Underwater Cultural Heritage Preservation Act, which follows the Convention on the Protection of the Underwater Cultural Heritage announced by UNESCO in 2001, was published by the Ministry of Culture to set an official standard for development and management in 2015. The guideline for UCH survey was soon be announced in the next year. All these acts lead Taiwan into the forefront of UCH survey in the world.
The techniques or methods used in UCH survey, as the rule in the UCH Preservation Act, must be non-destructive to reduce harm as much as possible. Marine geophysical techniques therefore become the major tools used in the UCH surveys in Taiwan. These tools include side-scan sonar for wide range seafloor mapping, multi-beam sonar for getting accurate position and 3-D image, magnetometer for finding ferromagnetic material, and sub-bottom profiler for searching buried objects. The requirements of using these techniques within UCH surveys are written in the official guideline.
After data analysis, the records from different instruments will be compared with others to identify the targets. However, the results of recognition involve objects unwanted, such as acoustic noise, rocks, or other nature features. Errors produced during the survey may also increase the difficulty of recognition. With the experience from previous research, this study will introduce some cases which were done before, and take a review of the official guideline to provide the suggestion that can help to improve the results of UCH survey in Taiwan.

Keywords: Underwater Cultural Heritage, marine geophysics, side-scan sonar