When people are asked to imagine a dream escape, they often envisage a scenic, remote island. At times, I've thought of Tahiti myself, in a rustic bungalow built on stilts over water. I have no modern gadgets, and focus on finishing a book, meditating or snorkeling before a meal. Images of dream destinations are often enhanced by satellite images of maps and detailed close ups. 

As we take a break from the life we know, and imagine where we're not, we seek to disconnect from our typical reality. Tourists caught in tsunamis are often focused on anything but a pending disaster. Even local people are caught off guard in Japan, Pacific Islands, Thailand, Sri Lanka and other places that have been hit. Just because you have a phone, tv, radio or Internet doesn't guarantee warning. The existence of tsunamis in modern days is largely unknown before it hits.

Back in 2000, during some of my research on the impact of El Nino in the south pacific coastal region of South America, I'd seen and heard proposals for warning systems on buoys, sensors and satellites. This wasn't immediately dismissed as impossible, but cost was viewed as prohibitive by government and industry. There existed a lack of collective will, lack of desire to spend or to be proactive. Key actors prefer to respond to a crisis and then, disband to focus on other matters.

Since the 2004 tsunami which caused the deaths of 300,000 people in the southeastern pacific, governments of coastline nations have agreed on the urgency for a global tsunami warning system. They do not agree, however, on who will pay for manufacturing, installing and monitoring it. I think more now about people on islands without communication equipment. Although money has been spent by leaders on new sensors and radios, I decided to review satellite buoy warning systems and how they had been mplemented since my initial view of the technology.

In case you're unaware, tsunamis mainly evolve from huge quakes. A global network of sensors already exists to detect and measure seismic activity. Yet, not all ocean quakes lead to massive waves. Available seismic data doesn't tell you much on the direction or speed of incoming waves. Where some regional tsunami warning systems draw only from seismic data, such systems aren’t trusted. The only way to confirm if a tsunami is brewing is to observe moving waves close-up. Tsunamis initially appear small at the surface, even near a quake’s epicenter. The height may be as low as a few centimeters. Only as waves approach land do they swell to frightening sizes. This trait makes detection hard, requiring high-tech equipment.

The first method used to supplement seismic data was taking readings from tide gauges. Although some tide gauges are very sophisticated, many are basic mechanical devices that measure height of a float protected from waves by an enclosure called a stilling well. Because tide measurements require a fixed point of reference, tide gauges are normally installed on or near a coast. They're easily accesible for maintenance and sensors there are only really useful for a short distance. The question of how many buoys would be necessary for a comprehensive global system, where they would be placed, how they would be maintained and by whom, remain unanswered questions. Sounds like a situation for a United Nations of space affairs, yet such an entity doesn't yet exist.

A more direct way of detecting tsunamis out at sea is to measure pressure changes on the ocean floor. The Deep-ocen assessment and Reporting of Tsunamis (DART) program, is now used in the Pacific ocean. Bottom-mounted sensors detect changes in pressure known for a typical tsunami. The sensors relay the information via sonar to a buoy floating on the ocean surface. Buoys, in turn, transmit the data to a satellite, which relays data to ground-based stations for processing. DART does improve speed and accuracy of tsunami warnings. The downside is existing sensors and buoys are prone to failure and must be serviced or replaced lots. Experts agree there aren't enough specialized buoys or satellites to monitor all oceans.

Nice to know there's always hope. Tsunamis at sea are invisible to an eye, but radar satellites will detect them, if pointed in the right place at the right time. The issue with these satellites, other than they may not detect the problem, is that the data they produce must be relayed and processed on Earth.The hours required can't provide early warnings. Future generations of satellites, however, may overcome such limitations. There's always the chance we will grow to better understand the root cause of why tsunamis occur and circumvent rather than influence the cause. Otherwise, using satellites or any other technology strategy would simply be like putting a bandaid on a wound, or only dealing with the symptoms of real issues.