One of these applications is the use of optical fibers to collect scientific data about the ocean. There are several different ways to do this, but earthquake and tsunami warning systems are among the more common applications. These use submarine fiber optic cables to connect a series of seismic monitoring units placed on the sea floor. The cables deliver the data collected by these units to shore stations at the speed of light.
Warning systems using cables have several advantages over other types of systems, such as buoys. The transmission speed over fiber optics is higher than that of the satellite links typically used for buoys. Also, buoys require considerable maintenance and can be out of service for some time before they can be repaired.
The downside of cabled warning systems is that they are very expensive. The cost of such a system can be US$ 30,000 or more per kilometer. Funding on that scale is rarely available for a purely scientific project.
This is why many of the relative handful of cabled earthquake and tsunami warning systems are located in the Pacific “Ring of Fire.” These nations have had to deal with devastating tsunamis in the past and have invested large sums of money to attempt to mitigate the human and economic suffering that they cause.
Taiwan is one of the leaders in this field. Its Central Weather Bureau (CWB) has been working to improve the early warning capability for earthquakes and tsunamis off the eastern coast of Taiwan since the establishment of the Marine Cable Hosted Observatory (MACHO) project in 2007.
The CWB has continued to invest in tsunami warning technology and at the end of 2020 unveiled a new cabled seismic and tsunami observation system. Delivered by NEC Corporation, the 620-kilometer-long submarine cable network reaches a depth of 5,800 meters and includes optical submarine cables, submarine observation units, and optical submarine repeaters, all manufactured and assembled at NEC factories in Japan.
According to the CWB, when an earthquake occurs in the eastern sea area of Taiwan this new system can provide an emergency warning more than 10 seconds before the actual tremor is felt on land. Moreover, a warning can be issued 20 to 30 minutes before a tsunami reaches the coastal area. As a result, this system will contribute to the enhancement of disaster prevention and mitigation capabilities. For example, public transportation systems, including MRTs (Mass Rapid Transit) and HSRs (High Speed Rail) can quickly decelerate in the event of an earthquake.
CWB is not stopping there. It reported earlier in 2020 that it in talks with the government of the Philippines on extending its tsunami warning system to the Philippine island of Luzon. This system would be one of the longest (approximately 800 kilometers) and one of the few truly international cabled observatories to date.
This story was originally featured in ON&T Magazine’s February 2021 issue. Click here to read more.
