BETTER LIVING

By David Khorram
Special to the Saipan Tribune

How do we know if a tsunami is on the way to the CNMI? This is a question that has been on the minds of many since the devastation that came to many countries around the Indian Ocean, with no warning. The loss of life has been staggering, and the worldwide response has been a sign of the oneness of mankind. Yet many of us may wonder how things might be different here if a tsunami were to come.

Pacific Tsunami Warning Center Monitors Earthquakes: The Pacific Ocean, unlike the Indian Ocean, does have a tsunami warning system in place. The Pacific Tsunami Warning Center was established in 1949 in Hawaii to provide warning to countries and jurisdictions around the Pacific ocean. Tsunamis are classified as either local, regional or Pacific-wide. They can be caused by a variety of disruptions to the ocean, such as landslides, volcanic eruptions, meteors, and of course earthquakes. The destructive regional and Pacific-wide tsunamis are caused by earthquakes, and for that reason, the PTWC monitors earthquakes.

Tsunami Bulletin: There are some 150 sensors throughout the Pacific that scan for underwater earthquakes. If there is an earthquake of magnitude 6.5 or greater anywhere in the Pacific, a signal is sent to PTWC. An earthquake must be of magnitude 7.5 or greater to generate a tsunami, so the 6.5 threshold is a safe threshold. If the earthquake is between 6.5 and 7.5, PTWC sends out a “Tsunami Bulletin,” which will basically say that an earthquake has occurred, but there is no risk of a tsunami.

Tide Sensors and Tsunami Watch/Warning: If the earthquake is greater than magnitude 7.5, which is large enough to generate a tsunami, then PTWC takes the next step. It checks automatic tide sensors in the area of the earthquake to see if a tsunami might have been generated. This is not an easy task. If PTWC thinks that a tsunami has been generated, they issue a “Tsunami Watch/Warning.” A tsunami in the open ocean is not visible from the air or by satellite. In fact, the height of a tsunami wave in the open ocean may only be a few feet. The passing wave of energy actually extends from the surface all the way to the ocean floor, and so in deep water, the passing tsunami may only be a gentle swell, unnoticeable by a boat or a ship out at sea. When the wave approaches the coastline, the water “piles up” and becomes a catastrophic wall of water that can be stories high. If you get onto the PTWC website during the next Tsunami Watch/Warning, you may see that the height of the wave is two feet at a particular sensor. If this sensor is in the deep ocean, this two feet high wave could become a 40 feet wave at a coastline. Just because it’s a small wave out at sea doesn’t mean that it’s a “safe” wave. So, interpretation of the data from tide monitors can be quite difficult.

75 percent false alarms: In general, there is no method to determine if a tsunami has been generated except by actually detecting the arrival of characteristic waves at the network of tide sensors. It’s kind of a “watch and see” process. But because tsunami waves can travel so fast—up to 600 miles per hour—there is an urgency to get the warnings out quickly. This is why about 75 percent of the Tsunami Watch/Warnings that are issued are cancelled. Although in many ways it’s better to be quick to issue warnings, the effect is that when 75 percent of the warnings don’t result in a tsunami, people get tired of “false alarms” and are reluctant to evacuate every time there is a warning.

Warning arrives at EMO: So, here we are in the CNMI, and the PTWC sends out a “Tsunami Watch/Warning.” How do we get the warning, and what happens once the warning arrives? I spoke to Mr. Rudy Pua, the director at the Emergency Management Office, who kindly explained the process. EMO is part of the Aeronautical Fixed Telecommunication Network, which is an international message system that is used primarily by air traffic control, aeronautical information services and meteorological services. This message system is monitored 24 hours a day by EMO staff. When a Tsunami Watch/Warning comes in through AFTN, EMO contacts the National Weather Service in Tiyan, Guam, to confirm the occurrence of the earthquake, and to see if any further information is available regarding the generation of a tsunami wave.

Public Alert System: At this point, the “Early Warning System” is activated, which means the CNMI public is alerted. The public alert takes place through a call to 1080 AM radio station, which announces the warning. The alert is then picked up by the other radio stations. The Department of Public Safety is also notified, and DPS personnel fan out to low-lying costal areas with bullhorns to inform the population to move to higher ground. “Higher ground” means the areas of As Matuis, Capitol Hill, Navy Hill, the NMC area, and the main road along Papago. You don’t have to go to the top of Mt. Tapachau. Over the past 12 years that I’ve been here, I remember about three tsunami alerts. During the first one, I lived in an apartment building right on Beach Road. The tsunami alert came during the middle of the night. My neighbors and I found out about it the next day. The two other tsunami alerts came during the day, and many of us recall the general confusion and chaos, and the traffic jam going up Capitol Hill. With the current system, if a tsunami of serious proportions were to hit the CNMI, many of us would die. If you sleep through the bullhorn, or if you’re at a secluded beach, or if no one around you is listening to the radio, you’ll never have a chance to evacuate.

A Siren System? Where I grew up, in a rural valley in the Appalachian mountains of Kentucky, there was a risk of tornadoes. The town had a siren system. Every Saturday at noon, the siren would sound for one minute, just as a test. We all knew that if we heard the siren at any other time, it meant “Tornado warning! Go to your basement!” I asked Mr. Pua if such a system had been considered for the CNMI—a network of sirens around the island that would mean “Tsunami warning! Move to higher ground!” In fact, such a system had been considered, and may have even existed here in the past. But such systems are expensive to maintain, and for this reason, it has not been revived.

The Challenge: In fact, it is widely recognized that even with improved predictability of tsunami formation, the challenge is to get the word out. This is especially the case in places like Southeast Asia, where many coastal communities do not have access to modern communication systems or transportation routes to higher ground. There is very little time, and people have to be prepared to evacuate at a moments notice. It is a formidable challenge.

Afterthought: When I was a medical student, one of my professors asked me why I study so hard. My response was that I was afraid that if I didn’t know enough, someday someone might die. “David,” he said, “Even if you do know enough, someday someone will die.” Even with the best of tsunami warning systems, the finest local alert system, and the ideal evacuation plans, inevitably people will die. Perhaps this is the most sobering aspect of such cataclysmic events: that we are forced to pause and see our own mortality before the indiscriminate and awesome forces of nature. And perhaps the biggest individual challenge now is to not just come up with a good plan to escape death, but rather to come up with a great plan to live a meaningful life.

(David Khorram, MD is a board certified physician and a columnist for the Saipan Tribune. Questions and comments are welcome. Email davidkhorram@hotmail.com. Copyright © 2004 David Khorram.)