USGS Scientist in American Samoa Helps Calm Fresh Tsunami Fears

By Helen Gibbons November 2009

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Residents of American Samoa were still dealing with the aftermath of the September 29, 2009, tsunami that caused severe damage and 191 deaths in the region when the Pacific Tsunami Warning Center (National Weather Service) issued another tsunami warning on October 7. This warning was prompted by two submarine earthquakes, of magnitude 7.6 and 7.8, that struck within minutes of one another near Vanuatu, about 2,500 km (1,600 mi) west of American Samoa.

U.S. Geological Survey (USGS) scientist Bruce Jaffe was in American Samoa to study the impacts of the September 29 tsunami and was able to help with the response to the new tsunami warning. In a report to managers and scientists at the USGS, Jaffe wrote: "…people were in a state of panic, and many of the roads were nearly gridlocked as people tried to get to their homes. I went to the command center, told them that the event did not likely generate a tsunami that would be large in American Samoa, and led them through the data I used to come to that conclusion." Jaffe also called a radio station to let people know that the consensus of the group of tsunami scientists in American Samoa to study the September 29 event was that it was unlikely that the islands would be hit by a large tsunami from the new earthquakes. He also urged people to remain calm and to listen for emergency announcements as more information became available. The warning was called off about 1 hour before the arrival of the tsunami, just a few centimeters high, in Pago Pago.

Above: Tsunami waves generated by two earthquakes near Vanuatu in the southwestern Pacific Ocean on October 7, 2009, spread across the entire Pacific basin, but initial information indicates amplitudes of less than 1 m on most of the shores they struck. Excerpt from tsunami-propagation animation at NOAA Pacific Marine Environmental Laboratory’s Web page for the October 7 event. [larger version]

The first of a USGS rapid-response team to arrive in American Samoa, Jaffe was working with an International Tsunami Survey Team on the island of Tutuila to collect data on various physical characteristics of the September 29 tsunami waves—such as water height, flow directions, and distance traveled inland. It is hoped that their observations, and those made by other teams in the region, will help decrease losses in future tsunamis in American Samoa and elsewhere.

USGS Scientists Respond to Deadly Samoa Tsunami November 2009

Tsunami Event Series - October 7, 2009 Vanuatu and Santa Cruz Islands NOAA Center for Tsunami Research

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November 2009

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in this issue:

cover story:
Impacts of Ocean Acidification on Coral Growth

Scientists Respond to Samoa Tsunami

Scientist in American Samoa Helps Calm Tsunami Fears

Groundwater Studies on U.S. West Coast and Hawai'i

Summer Student Fellows Assist in Scientific Investigations

Frank Shipley is New Western Regional Chief Scientist

November 2009 Publications List