How to Forecast a Wave

Indian Ocean Tsunami Tests NOAA’s New Forecast System

Pacific Tsunami Warning Center.

Pacific Tsunami Warning Center.

High resolution (Credit: NOAA)

On August 10 at 12:56 p.m. PDT, a 7.7 magnitude earthquake struck the Indian Ocean. It happened near the Andaman Islands, north of the epicenter of the Dec. 26, 2004, earthquake that triggered a tsunami that killed a quarter of a million people. That’s when the scientists at NOAA’s National Weather Service Pacific Tsunami Warning Center (PTWC) sprang into action to create a fast and accurate tsunami forecast.

Less than one hour after the earthquake occurred, a tsunami was measured in real time by a DART (Deep-ocean Assessment and Reporting of Tsunamis) buoy located in the Indian Ocean.

DART buoy.

DART buoy.

High resolution (Credit: NOAA)

Reports from a tide gauge near Yanam, India, confirmed the model forecast when it reported a 3.9 inch (10 cm) high tsunami, which went unnoticed by the public. This tsunami provided the first test of NOAA’s new tsunami warning system and validated the collaborative effort to save lives and property during any tsunami event.

“With the DART data and new forecast system, we were then able to cancel the watch with confidence that no destructive tsunami had been generated,” said PTWC’s Deputy Director Stuart Weinstein. The PTWC watch and cancellation messages went to 26 Indian Ocean warning points.

Advanced Technology Saving Lives

Since 1997, Vasily Titov, Ph.D., and his team at NOAA’s Pacific Marine Environmental Laboratory (PMEL) have been working on a new forecast system to provide faster and more accurate forecasts of approaching tsunamis.

DART animation.

Propagation dynamics of the research forecast model computed with the MOST.

Quicktime animation [MOV] (Credit: NOAA)

NOAA’s research and ability to forecast tsunamis has greatly improved since the 2004 tsunami. This time, PTWC issued a tsunami watch based on initial earthquake information to all countries around the Indian Ocean.

 “Now we have forecast models set up in the area that were not available in 2004 to help us determine what type of impact we would see at various coastline communities,” Titov said.

The new forecast system, which includes DART buoys and forecast models, was installed at the tsunami warning centers in Hawaii and Alaska in June 2009. The Aug. 10, 2009, Indian Ocean earthquake and tsunami provided the first operational test — just months shy of the fifth anniversary of the 2004 tsunami event. 

This successful test shows the progress NOAA has made since 2004, when no information about the Indian Ocean tsunami was available in real time. And there were no warning contacts in the 26 Indian Ocean nations to receive the information and take appropriate action.

Maximum wave amplitude distribution created with the MOST forecast model. Triangles indicate DART buoys. 

Maximum wave amplitude distribution created with the MOST forecast model. Triangles indicate DART buoys. 

High resolution (Credit: NOAA)

The Indian Ocean DART buoy, designed by PMEL and deployed by NOAA’s National Buoy Data Center in December 2006, was a gift to the Kingdom of Thailand from the United States.

Since that time, this DART station has captured two non-destructive tsunamis and relayed the tsunami data in real time to the PTWC and other Indian Ocean nations via the Internet.

“We were very excited by our contribution to this important tsunami forecast system, it truly shows a “one NOAA” in action,” said NOAA’s NDBC Deputy Director Kathleen O’Neil.

The National Data Buoy Center operates 39 DART stations for the United States.

To learn more, visit NOAA’s National Data Buoy Center or Tsunami Web sites. NOAA logo.