| mount of warning time a tsunami warning system | | | | Five stations are located in the Atlantic, Caribbean, |
| can provide depends on the distance between your | | | | and Gulf of Mexico, and the remaining 34 in the |
| location and the location of the undersea event. A | | | | Pacific. The DART system is made up of a pressure |
| tsunami can travel 500 to 600 mph in deep water, | | | | sensor resting on the ocean bottom that transmits |
| slowing as it approaches shore. If the undersea | | | | continuous data by acoustic telemetry (sound |
| earthquake that starts the tsunami is 500 miles | | | | waves) to a surface buoy anchored near the |
| offshore in deep water, for example, and the | | | | pressure sensor. The buoy is equipped with satellite |
| tsunami is headed your way, local authorities will be | | | | link that relays the real time information to tsunami |
| notified within minutes of the event and will have | | | | warning centers around the world. Certain fluctuations |
| about one hour to issue the warnings to the public | | | | in ocean bottom pressure can indicate the presence |
| and start announcing directions for evacuation to a | | | | of a tsunami. |
| safe area. | | | | Many other kinds of reporting stations and |
| In doing research for my adventure novel TSUNAMI, | | | | observatories are used in the larger international |
| I found that in some cases, a local earthquake or | | | | reporting network. These include pier-based and |
| undersea landslide close to shore can initiate a | | | | satellite-based tidal gauges that track the height and |
| tsunami that strikes almost without warning. In 1998, | | | | length of passing tsunami waves, and seismometers |
| a 7.0 magnitude undersea earthquake near Papua, | | | | buried in ocean bottom caissons that measure the |
| New Guinea, triggered a massive submarine landslide | | | | magnitude of an undersea earthquake and determine |
| that started a 50-ft. tsunami close to shore. The | | | | its location. |
| wave hit the shoreline within minutes and wiped out | | | | One of the most well known undersea seismometer |
| several villages along the New Guinea coast, stripping | | | | projects is the Hawaii2 Observatory (H2O) located in |
| the land almost bare. 2200 people died. | | | | deep water between Hawaii and California. The |
| However, most major tsunamis are started by | | | | observatory was placed next to a retired undersea |
| undersea earthquakes in deep water. In the Pacific | | | | AT&T telephone cable so that the cable could |
| Ocean, a quake will be picked up by seismometers, | | | | be used to power the observatory. The observatory |
| pressure sensors, and tidal gauges at the reporting | | | | package includes a broadband seismometer, |
| stations of the Pacific Tsunami Warning System | | | | geophone, hydrophone, and pressure sensor |
| operated by 26 nations bordering the Pacific Basin. | | | | developed by the Woods Hole Oceanographic |
| The collected data registers on the instruments at | | | | Institution and the University of Hawaii. |
| the Pacific Tsunami Warning Center in Ewa Beach, | | | | The installation was performed by ROVs (remotely |
| Hawaii. The scientists at the Ewa Beach warning | | | | operated submarine vehicles) controlled from a |
| center can then determine the location, earthquake | | | | mother ship. The ROVs drilled a borehole, sunk a |
| magnitude, tidal variations, and changes in ocean | | | | caisson into the hole, then inserted the seismic |
| pressure. If readings indicate the disturbance may | | | | package into the caisson and sealed it. The seismic |
| have started a tsunami, warnings are issued | | | | package is connected to an adjacent junction box |
| immediately to the areas in danger with approximate | | | | operated with 400 watts of power fed from the old |
| arrival time of the first wave. | | | | telephone cable. The sensor information is |
| If an undersea event happens near Alaska or | | | | transmitted by fiber optic cable to a relay station on |
| anywhere along the West Coast of the U.S., the | | | | a surface buoy, which sends the data to the internet |
| instrument signals are picked up by the West Coast | | | | so that it can be used by tsunami warning centers |
| & Alaska Tsunami Warning System | | | | and by universities and scientific laboratories around |
| headquartered in Palmer, Alaska. There the same | | | | the world. The H2O installation has had many |
| procedure is followed. Immediate warnings are issued | | | | problems and has never performed up to |
| to local authorities in the areas at risk. | | | | expectation. However, the overall tsunami warning |
| As part of the international tsunami warning network, | | | | system works well. The entire system has |
| the United States has recently completed its own | | | | undergone successful testing. |
| U.S. Tsunami Warning System that takes in the | | | | If you live on or near the beach and if your local |
| Pacific Tsunami Warning System, the West Coast | | | | authorities issue a tsunami warning, take it seriously |
| & Alaska Tsunami Warning System, and the | | | | and follow evacuation directions. Do not hang around |
| Atlantic Tsunami Warning System. The U.S. system is | | | | the shoreline to watch the tsunami. It could cost you |
| composed of 39 DART (Deep Ocean Assessment | | | | your life, because the wave can be up to 100 feet |
| and Reporting of Tsunami) and DART II stations. | | | | high and moves much faster than a person can run. |