Coastal Processes, Hazards, and Society

Detecting Tsunamis: The US Tsunami Warning Center


Detecting Tsunamis: The US Tsunami Warning Center

Video: NOAA Tsunami Forecasting (2:33)

Click for a transcript of the NOAA Tsunami Forecasting video.
EDDIE BERNARD: Well, on December 26, 2004, there was a catastrophic earthquake, magnitude 9, that generated the world's most devastating tsunami in recorded history. And it occurred about 7:00 in the morning local time. And by noon, about 237,000 people were killed. It was a phenomenal event that will go down in history and not ever be forgotten. Well, there were several reasons that so many people died. First of all, there was not an awareness of the tsunami threat. The Indian Ocean had no tsunami warning system because the last destructive tsunami they'd had was 1945. So that was the context in which this whole thing was unfolding. And it was at that point in time we realized we had a golden opportunity to educate the public about tsunami awareness. And it didn't take much because the visuals that were coming in from that, all you had to do is just remind people that this can happen to anyone on the beach. And then there's three safety rules to follow. If the earth shakes, if the water recedes, or if you hear a loud roar, bingo. We try to get that simple message out as quickly as we could. We at the Pacific Marine Environmental Laboratory have been working the last 30 years to try to forecast a tsunami. That's been our whole objective. How could we forecast a tsunami, tell you how big it's going to be in advance, and tell you what to expect when it arrives? And to that extent, the first thing we have to do is build an instrument that could detect a tsunami in the open ocean. Then you have to relay that information back to a warning center, so we can adjust it in a numerical model to do the forecast. And that's the birth of the DART buoy. And I'm happy to report that following the 2004 event, there was a large investment made in these two technologies that we've been working on for years. And now, we're forecasting tsunamis in advance. I think nature's too complicated for us to say we've got you covered. But I think at this stage of the game, our warning centers will be able to do very accurately the small tsunamis, up to the large tsunamis.

Today, in partnership with the USGS and NOAA, the US Tsunami Warning Center operates from Hawaii. The warning center was first created after WWII as a result of the 1946 Aleutian Island tsunami that originated between Alaska and Siberia. The tsunami produced incredibly destructive waves that traveled hundreds of miles to the south and resulted in the severe inundation of Hilo Bay, Hawaii and led to numerous deaths. Formerly initiated in 1949, the center expanded in the aftermath of the 1960 Chilean earthquake that not only destroyed many communities along the coast of Chile but also led to more destruction in Hawaii and even in Japan on the opposite side of the Pacific Ocean. With such severe long-distance impacts, it was clear that individual nations needed to collaborate in order to effectively save lives. As a result, efforts were initiated to coordinate monitoring around the Pacific, but even in 2004, the effectiveness of the center was limited as demonstrated by the 2004 Sumatran Tsunami that impacted much of the Indian Ocean. Although the earthquake and tsunami were detected from the Pacific, little could be done to monitor its progression in the Indian Ocean, and efforts were more or less futile in terms of issuing effective warnings to residents living around the Indian Ocean basin. As a result of that event, the center now coordinates with other tsunami warning centers in the U.S.and with the United Nations and similar agencies in several other countries including Japan, Australia, and others. These centers not only detect earthquake activity but also track the development and movement of tsunami waves as they travel across the world’s oceans. The main missions of these centers are to monitor and issue warnings, advisories, and watches to help reduce the loss of life associated with these events around the world.

Onlookers observe inundation of town below.
USGS Photo from 1960 Onagawa Japan when tsunami waves from the Chilean earthquake inundated coastal areas on the entirely opposite side of the Pacific Ocean. Waves came ashore some 20 hours after the actual earthquake.

The US Tsunami Warning Center is a great resource that provides details about specific events around the globe that are being monitored for tsunami generation. Australia and a few other countries maintain similar websites. It is worth spending a little bit of time exploring the types of tools and data that these agencies are collecting and monitoring to help keep the public as safe as possible from these types of catastrophes. It is, however, up to individuals and communities to be educated about tsunami risks and hazards and to act on the information provided in order to save lives. Individual communities are ultimately responsible for developing evacuation plans and limiting shoreline development, in especially susceptible areas. These topics will be explored in greater detail in later modules.

It’s clear that tsunamis pose an incredible threat to coastlines and societies around the world; but exactly what are tsunamis, how are they formed, and how do they interact with coastlines around the world? In order to answer these questions, we will explore two case studies. The first is the Sumatran Tsunami that occurred in December 2004, and the second is the 2011 Japanese Tsunami that devastated the island of Honshu, one of Japan’s main islands.