Modern World Security Systems
Scientists are constantly trying to learn new ways to predict the behavior of tsunamis. Given current technology however, most tsunami data come to us after the damage has already occurred.
In a post-tsunami survey, geologists measure a number of factors. Scientists are particularly interested in the inundation and run-up features after the waves strike land. Inundation is the maximum horizontal distance penetrated inland. Run-up refers to the maximum vertical distance above sea level that the waves reached. Inundation and run-up are often determined by measuring the distance of killed vegetation, scattered debris along the land and eyewitness accounts of the incident.
Scientists have made great strides in monitoring and predicting the ongoing threat of tsunamis. One center continuously monitoring seismic events and changes in the tide level is the Pacific Tsunami Warning Center (PTWC). The center is located in Ewa Beach, Hawaii, and services the Hawaiian Islands and surrounding U.S. territories by working in conjunction with other regional centers. The West Coast & Alaska Tsunami Warning Center (ATWC) in Palmer, Alaska, serves the Aleutian Islands area along with British Columbia, Washington state, Oregon and California. This center is of particular importance because submarine earthquakes in this region have created waves that moved throughout the Pacific Ocean before striking elsewhere.
Tsunamis are detected by open-ocean buoys and coastal tide gauges, which report information to stations within the region. Tide stations measure minute changes in sea level, and seismograph stations record earthquake activity. A tsunami watch goes into effect if a center detects an earthquake of magnitude 7.5 or higher. Civil defense agencies are then notified, and data from tidal gauge stations are closely monitored. If a threatening tsunami passes through and sets off the gauge stations, a tsunami warning issues to all potentially affected areas. Evacuation procedures in these areas are then implemented.
The Deep-Ocean Assessment and Reporting of Tsunamis (DART) uses unique pressure recorders that sit on the ocean bottom. These recorders are used to detect slight changes in the overlying water pressure. The DART system can detect a tsunami as small as a centimeter high above the sea level.
NASA is also heavily involved in the quest to predict deadly tsunamis before the occur. In 2010, researchers at NASA's Jet Propulsion Laboratory successfully demonstrated elements of a prototype tsunami prediction system. Using real-time data from the agency's Global Differential GPS (GDGPS) network, the system successfully predicted the size of the tsunami following the Feb. 27, 2010, Chilean earthquake. In the future, such a system may enable more effective advance warning of incoming waves. In the instance of the 2011 Japan tsunami, the warning systems worked fine. Rather it was the unanticipated size of the event that proved so deadly. That leads us to the biggest problem with tsunamis: Once in motion, they can't be stopped. Scientists and civil agencies can only devote resources to predicting tsunamis and creating effective plans for protecting coastal areas from their ravages.
In 2005, Chile started to implement the Integrated Plate boundary Observatory Chile (IPOC) which in the following years become a network of 14 multiparameter stations for monitoring the 600-km seismic distance between Antofagasta and Arica. Each station was provided with broadband seismometer, accelerometer, GPS antenna. In four cases, it was installed a short-base tiltmeter (pendulum). Some stations were ubicated underground at a depth of 3-4 meters. The network completed the tidal gauge of the Hydrographic and Oceanographic Service of the Chilean Navy.
The long-base tiltmeters (LBTs) and the STS2 seismometer of the IPOC recorded a series of long-period signals some days after the 2010 Maule earthquake. The same effect was registered by broadband seismometers of India and Japan some days after the 2004 Indian Ocean earthquake and tsunami. Simulations held in 2013 on historical data highlighted "tiltmeters and broadband seismometers are thus valuable instruments for monitoring tsunamis in complement with tide gauge arrays." In the case of the 2010 Maule earthquake, tilt-sensors observed a discriminating signal "starting 20 min before the arrival time of the tsunami at the nearest point on the coastline."
Indian Ocean (ICG/IOTWMS)
Tsunami Early Warning Tower board in Hikkaduwa, Sri Lanka
After the 2004 Indian Ocean Tsunami which killed almost 250,000 people, a United Nations conference was held in January 2005 in Kobe, Japan, and decided that as an initial step towards an International Early Warning Programme, the UN should establish an Indian Ocean Tsunami Warning System. This resulted in a warning system for Indonesia and other affected areas. Indonesia's system fell out of service in 2012 because the detection buoys were no longer operational. Tsunami prediction is therefore currently limited to detection of seismic activity; there is no system to predict tsunamis based on volcanic eruptions.
North Eastern Atlantic, the Mediterranean and Connected Seas (ICG/NEAMTWS)
The First United Session of the Inter-governmental Coordination Group for the Tsunami Early Warning and Mitigation System in the North Eastern Atlantic, the Mediterranean and connected Seas (ICG/NEAMTWS), established by the Intergovernmental Oceanographic Commission of UNESCO Assembly during its 23rd Session in June 2005, through Resolution XXIII.14, took place in Rome on 21 and 22 November 2005.
The meeting, hosted by the Government of Italy (the Italian Ministry of Foreign Affairs and the Italian Ministry for the Environment and Protection of Land and Sea), was attended by more than 150 participants from 24 countries, 13 organizations and numerous observers.
A Caribbean-wide tsunami warning system was planned to be instituted by the year 2010, by representatives of Caribbean nations who met in Panama City in March 2008. Panama's last major tsunami killed 4,500 people in 1882. Barbados has said it will review or test its tsunami protocol in February 2010 as a regional pilot.
Tsunami warning system in East Timor
Regional (or local) warning system centers use seismic data about nearby recent earthquakes to determine if there is a possible local threat of a tsunami. Such systems are capable of issuing warnings to the general public (via public address systems and sirens) in less than 15 minutes. Although the epicenter and moment magnitude of an underwater quake and the probable tsunami arrival times can be quickly calculated, it is almost always impossible to know whether underwater ground shifts have occurred which will result in tsunami waves. As a result, false alarms can occur with these systems, but the disruption is small, which makes sense due to the highly localized nature of these extremely quick warnings, in combination with how difficult it would be for a false alarm to affect more than a small area of the system. Real tsunamis would affect more than just a small portion.
Japan has a nationwide tsunami warning system. The system usually issues the warning minutes after an Earthquake Early Warning (EEW) is issued, should there be expected waves. The tsunami warning was issued within 3 minutes with the most serious rating on its warning scale during the 2011 Tōhoku earthquake and tsunami; it was rated as a "major tsunami", being at least 3 m (9.8 ft) high. An improved system was unveiled on March 7, 2013 following the 2011 disaster to better access the waves.