Preventing disaster
An earthquake expert who saw the warning signs
DEEP OCEAN SENSORS/BUOYS
Deep ocean sensors are the most effective detection device, picking up subtle pressure changes as tsunami waves pass by. Buoys transmit the data to warning centers via satellite.
TIDE GAUGES
These sea-level detectors measure the rise and fall of tides. They can also give the first indication of whether tsunami waves are spreading outward from underwater quakes.
A COMMUNICATIONS SYSTEM
REAL-TIME ACCESS
No matter what detectors are in place, seismologists in regional warning centers need data fast to initiate emergency response plans--or avert false alarms. Some options: VHF radio, satellite, microwave transmissions, and dedicated land lines.
GETTING OUT THE INFORMATION
Tsunami monitors halfway around the world picked up signs of the December 26 earthquake within 15 minutes but had no contacts in the region. Warning systems, from cellphone alerts to sirens and loudspeakers, are essential, as is a network of local warning centers.
PREPARING THE PUBLIC
Tsunamis travel fast, and for nearby areas "early warning" can mean minutes, or less. Public education can help citizens recognize impending danger and warning sirens, learn how to escape, and locate food, water, and shelter after the event.
[Map Labels]
9.0 earthquake December 26 epicenter
Proposed tsunami detector sites
AFRICA
Subduction zone
Earthquake zone: One plate moves under another
Arabian Sea
Maldives
India
Sri Lanka
SUNDA ARC
Indian Ocean
Bay of Bengal
Burma
Thailand
Malaysia
Indonesia
Japan
Philippines
AUSTRALIA
Pacific Ocean
Sources: DM Solutions, Dr Simon Day (University College London and University of California-Santa Cruz), NOAA, UNESCO
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