Tsunami warning systems are usually built in the aftermath of epic waves. After a half century of brutal lessons learned, the Pacific tsunami safety net has grown into a robust network of observatories, buoys, and international collaboration.
A powerful magnitude-8.3 earthquake struck just off the coast of Chile on Wednesday evening, generating a dangerous 15-foot tsunami along parts of the Chilean coast and triggering tsunami advisories in Hawaii and southern California.
The tsunami is expected to fan out across much of the Pacific Ocean, according to The Weather Channel. Its power is concentrated westward toward French Polynesia, including Tahiti, with the lead tsunami waves already reaching as far west as the Chatham Islands (part of New Zealand), where a 1.2 foot wave height was measured at Owenga.
Official tsunami warning capability in the US began in 1949, in response to a 1946 tsunami generated in the Aleutian Islands that wreaked havoc on Hilo, Hawaii. The federal government already housed the Honolulu Geomagnetic Observatory in ʻEwa Beach, and the Pacific Tsunami Warning Center moved in.
Following the 1960 Chilean earthquake and tsunami which devastated Chile and killed dozens in Hawaii, and as many as 200 people in Japan, Pacific nations moved to coordinate efforts. Under direction from the United Nations, the Intergovernmental Oceanographic Commission (IOC) established the Intergovernmental Coordination Group for the Pacific Tsunami Warning System (ICG/PTWS) in 1968. The US offered the ʻEwa Beach center as the operational headquarters.
Similarly, in Alaska, PTWC issued tsunami warnings until 1967 when the West Coast & Alaska Tsunami Warning Center (WCATWC) was established in response to the 1964 Alaskan earthquake and tsunami. In 1982, the WCATWC area of responsibility was enlarged to include California, Oregon, Washington, and British Columbia.
In the aftermath of the 2004 Indian Ocean tsunami that claimed 230,000 lives, including some 170,000 in northern Indonesia alone, PTWC has taken on additional areas of responsibility, including the Indian Ocean, the South China Sea, the Caribbean Sea, Puerto Rico, and the US Virgin Islands, according to NOAA. PTWC's staff nearly doubled as a result of that tsunami – from 8 to 15 – and it now staffs the center around the clock.
A vital part of tsunami detection are deep ocean sensors that measure pressure from the sea floor and ping satellites with real-time data. Prior to the 2004 tsunami, there were 6 such buoys in places across the Pacific Ocean, in places NOAA deemed most at risk for big wave activity. Following the 2004 tsunami, the array was expanded to 39 buoys.
As the Christian Science Monitor previously reported, an magnitude-8.6 earthquake off of northern Indonesia in 2012 tested the systems put in place following the 2004 devastation:
Made up of seismographic stations and deep-ocean sensors, the Indian Ocean Tsunami Warning System was activated in June 2006 after an agreement at a United Nations conference in Japan.
When a quake hits, data is sent to the Pacific Tsunami Warning Centre in Hawaii and the Japan Meteorological Agency, which coordinate with national tsunami centres in the region.
It can take 15 to 20 minutes for quake data to be analysed and a tsunami watch to be issued to governments and the public around the Indian Ocean. Using their own data, nations warn citizens in a variety of ways – from radio, television, and text messages to sirens and mosque loudspeakers.
In Sri Lanka, officials pressed a "tsunami evacuation" button from an emergency control room in Colombo that alerted 75 warning towers across the island. Within 20 minutes, three million people had moved from the seashore to safer places.
At the time, Keith Loveard, chief risk analyst at Jakarta-based security firm Concord Consulting said, "The tsunami alert system worked to a degree.... While awareness has improved, reinforced by 2004, it still needs to get better through public education and government campaigns."