Macau | Sea level rise of 0.5 metres might double tsunami risk -expert

A research article published in Science Advances journal claims that a modest rise in sea levels of 0.5 metres could double the risk of a tsunami hitting Macau

Macau (MNA) – A research article published in Science Advances journal claims that a modest rise in sea levels of 0.5 metres could double the risk of a tsunami hitting Macau.

One of the researchers working on the study, principal investigator Adam Switzer of Earth Observatory of Singapore, told Macau News Agency (MNA) that an initial study had been conducted in 2014 and 2016 suggesting Macau was free of tsunami risk.

After studies conducted in the wake of Typhoon Hato, however, his organisation had decided to revisit the old study using predictions for rising sea levels.

“Using a Monte Carlo probabilistic tsunami hazard assessment (PTHA), we calculated the height of potential tsunamis generated by the Manila Trench by subdividing the fault zone into discrete regions to account for the effects of complex slip along the rupture. That work revealed that if the Manila Trench generated a large tsunami-producing earthquake places on the northern shores of the South China Sea like Macau would face a significant tsunami threat,” said Mr Switzer.

Switzer clarified that he meant that a magnitude of earthquake 8.8 would pose a tsunami risk in current conditions.

Assuming sea levels rose by 0.5 metres, the risk would apply for earthquakes of magnitude 8.3.

“As sea levels rise, smaller earthquakes would be able to create a bigger effect.”

A level of 0.5 metres [increase] is projected to occur by 2060.

When asked about the risk to certain areas of Macau, Mr Switzer picked out the Inner Harbour area as the area at highest risk. “Our work showed that for most part the potential tsunami flooding would be confined to the older parts of Macau. The area of most vulnerability is the densely populated Macau Peninsula, especially the Inner Harbour area in the west.”

Switzer added that the Inner Harbour area is the most susceptible to tsunami hazard due to its relatively low elevation of less than two metres above mean sea level and lack of coastal defences.

With regard to development, he notes that limited portions of coastlines in Taipa and Cotai are hazardous with sea level rises and large magnitude earthquakes.