臺菲VOTE計畫：馬尼拉隱沒帶的海洋及鄰近陸上地球物理調查(1/3)

Most of the recent destructive earthquakes occurred as megathrust events insubduction zones. Examples of these events are the 2004 Indian Oceanearthquake and tsunami as well as the 2011 Tohoku, Japan earthquake andtsunami. In the Philippines, the Moro Gulf earthquake and tsunami of 1976devastated the southern coast of Mindanao which resulted to casualtiesestimated at 5000-8000. Impacts of earthquakes to local populations are veryevident during the more recent events like the 1990 Luzon and 2015 Boholearthquakes. The recent discovery of a thick tsunami deposit in Dongdao Islandin the middle of the South China (Sun et al., 2013) signify the capacity of theManila Trench mega-thrust fault to generate very strong and destructiveearthquakes. These earthquakes can induce massive submarine landslides andtsunamis that impact the areas surrounding the South China Sea (SCS). Yangand others (2019) investigated Song dynasty ceramic shards in the Nan’ao Islandin the southeast coast of the Chinese Mainland (Guangdong Province) and foundevidence of a major tsunami event in AD1024, roughly 1000 years ago. Thisdevastating tsunami is also attributed to a large submarine earthquake with anapproximate maximum magnitude of Mw 8 along the Manila Trench. Theserecent discoveries are evidences of past large earthquakes and tsunamis in theSCS. Considering this information, there is a renewed interest in the seismogenicand tsunamigenic potentials of the Manila Trench mega-thrust fault. The jointresearch will investigate the Manila subduction zone utilizing marine and onshoregeophysical methods (i.e. gravity, magnetic, seismic reflection, and ocean bottomseismometer surveys). The offshore and onshore data will be integrated toproduce a more complete understanding of the subduction zone structure andprocesses from the marine trench region to the active volcanic arc and faultsonshore. Results of the proposed joint research are important for countriesbordering the South China Sea (i.e. Philippines. Taiwan, Vietnam, China,Malaysia, Thailand, and Indonesia) in terms of geohazards and disaster riskreduction. Considering the direct impact of an impending large magnitudeearthquake and tsunami to Metropolitan Manila, there is an urgent need toconduct this important research work.