太平洋海嘯警報中心
维基百科，自由的百科全书
太平洋海嘯警報中心（Pacific Tsunami Warning Center，簡稱PTWC），由美國國家海洋和大氣管理局管理，於1949年成立。中心因1946年造成165人死亡，發生於夏威夷與阿拉斯加的阿留申群島地震而成立，總部並設於太平洋的美國夏威夷州。太平洋海嘯警報系統亦由這個組織所運作。
太平洋海嘯警報系統的成員由太平洋沿岸各國組成，平日工作會不斷留意各地水位變化。在地震發生時，在太平洋海嘯警報系統架構下的各地天文台或地震預防中心會將地震儀所收集到的的數據，如：地震波抵達時間，一一發送到夏威夷州的太平洋海嘯警報中心。中心在接收到各地區之資料後，便會迅速計算出地震震央、深度和強度，從而評估出發生海嘯之機會，然後向參與的國家及地區發出詳盡的海嘯預測數據及報告，當中也預測了海嘯抵達太平洋沿岸各地區的大約時間和海嘯高度等。傳媒亦經常根據該中心之數據向市民傳遞最新的海嘯消息。
The Center uses seismic data as its starting point, but then takes into account oceanographic data when calculating possible threats. Tide gauges in the area of the earthquake are checked to establish if a tsunami wave has formed. The centre then forecasts the future of the tsunami, issuing warnings to at-risk areas all around the Pacific basin if needed. There are never false alarms — if the PTWC issues a tsunami warning for a particular area, the wave is already on its way and will hit. As it takes more time for tsunamis to travel trans-oceanic distances, the PTWC can afford to take the time to make sure of its forecasts.
[编辑] 深海海嘯探測
1995年，美國 National Oceanic and Atmospheric Administration (NOAA) began developing the Deep-ocean Assessment and Reporting of Tsunamis (DART) system. By 2001年 an array of six stations had been deployed in the 太平洋. [1]
始於2005年，as a result of heightened awareness due to the tsunamis caused by the 2004年印度洋大地震, plans were announced to add 32 more DART 浮標 to be operational 至2007年中. [2]
These stations give detailed information about tsunamis while they are still far off shore. Each station consists of a sea-bed bottom pressure recorder (at a depth of about 6000 m) which detects the passage of a tsunami and transmits the data to a surface 浮標 via acoustic modem. The surface buoy then radios the information to the PTWC via the GOES 衛星系統. The bottom pressure recorder lasts for two years while the surface buoy is replaced every year. The system has considerably improved the forecasting and warning of tsunamis in the Pacific.
