November 9th, 2015
This month Japan unveiled the most sophisticated tsunami warning system in the world, two years after the country was rocked by a massive tsunami which killed 19,000 people. Through the use of state-of-the-art under water pressure sensors and automatic mobile phone warnings, the goal is to avoid underestimations of how severe the waves would be which is part of what went wrong in 2011.
Japan has actually had some of the world’s first earthquake detection systems going as far back at the 1940’s. It even had an existing tsunami detection system in place when the over 9.0 earthquake hit in 2011. The trouble with that technology was that sensors were so sensitive that they became over saturated when the massive quake hit. To avoid this problem in the future, the new sensors, known as Broadband Strong Motion Meters (BSMM), have a lower sensitivity. 80 BSMM’s have now been installed across the country, while out in the sea 3 strategically placed DART sensors monitor the ocean floor. Sensors communicate seismic activity up to buoys that then transmit that activity to monitoring centers via satellite. Authorities have also invested in long-life batteries for all seismic sensors that used to have a problem of blackouts due to low power.
Despite all the technological improvements, time remains a very difficult obstacle to overcome. No matter how fast data can be transmitted and warnings get communicated, if an earthquake strikes close enough to a coast, there may not be enough time to evacuate. National statistics indicate that 40 percent of near shore tsunamis hit the Japanese coastline in 20 minutes after an earthquake. While others take less than 5 minutes. The time-goal of the new tsunami warning system, from detection to warning- 3 minutes.
Beyond Japan there are several less sophisticated tsunami warning systems in high risk parts of the world. The US government operates warning systems for the west coast of the US and Alaska, both of which have been historically impacted by tsunamis. After the 2004 Indian Ocean Tsunami, which killed 230,000 people, the United Nations established Indian Ocean Tsunami Warning System which includes the use of DART sensors. In the Caribbean, where 10 percent of the world’s tsunami’s occur, there have been initiatives to establish and test a warming system with help from the US and the United Nations. While there are no guarantees that there will be enough time to evacuate, the world has made some strides over the past 10 years when it comes to tsunami preparedness.
Source: The Daily Yomiuri
Photo: Stuart Hayes, NOAA/NWS/NDBC
tsunami warning systems, warning systems for tsunamis, tsunami alert system