by Elisa Hawkes
Coastal Journal staff
BATH — The Sagadahoc County Emergency Management Agency (EMA) implemented the CodeRED Emergency Warning Notification System on July 1. CodeRED is a telephone communication service providing notification to area residents, businesses and visitors in case of an emergency or severe weather event. The question facing the county is whether one of those emergency situations could involve a tsunami.
Put simply, it is possible for a mega-tsunami to result in unimaginable destruction along the entire East Coast of the United States. However, the probability of this happening is low – much lower than a catastrophic tsunami hitting the West Coast.
This is based upon scientific studies performed by such agencies as the National Oceanic and Atmospheric Administration (NOAA) and the National Weather Service.
In 2009, the Maine Emergency Management Agency (MEMA) received a grant from the National Tsunami Hazard Mitigation Program (NTHMP) to investigate the risk and threat from a tsunami to the Maine coast. Maine Geological Survey performed this task with the assistance of the West Coast/Alaska Tsunami Warning Center (WCATWC), a division of NOAA. The outcome of this project revealed that although Maine has a low tsunami risk, should a major event occur, it would impact the entire coast. The weakest area in existing county emergency plans was in warning coordination and public outreach.
MEMA created a culture of tsunami preparedness and response a plan including, “establishment of more tsunami resilient communities, effective and reliable warning dissemination to people at risk, improve local warning dissemination capabilities to people at risk, and improve community warning point capabilities.”
Sagadahoc EMA is responsible for dispatching police, fire and emergency medical services (EMS) to all towns within Sagadahoc County, including Arrowsic, Bath, Bowdoin, Bowdoinham, Georgetown, Phippsburg, Richmond, Topsham, West Bath and Woolwich. Sagadahoc County covers 370 square miles, including 254 square miles of land and 116 square miles of water. The estimated population for the county was nearly 36,500 in 2008. The CodeRED system will provide an effective method of informing many people of impending danger in a short amount of time.
Although the probability of a tsunami affecting the Maine coast is not great, it still exists. It is also impossible to predict when one may occur. Most mega-tsunamis are caused by the sudden vertical uplift of huge amounts of water after an earthquake, particularly when one tectonic plate slides beneath another (subduction). This type of activity caused the recent disastrous tsunami in Japan and the 2004 event in Indonesia.
The Atlantic Ocean lacks subduction areas, common in tsunami-related earthquakes. As a result, there is much less seismic activity in the Atlantic Ocean than in the Pacific. The potential for a mega tsunami on the East Coast comes from the Cumbre Vieja Volcano in the Canary Islands and the Puerto Rican Trench. The Canary Islands is a Spanish archipelago located just off the northwest coast of mainland Africa, between Morocco and the Western Sahara, and is part of Spain. The Lesser Antilles subduction zone near Puerto Rico has earthquakes much more capable of generating tsunamis in the North Atlantic than the Cumbre Vieja Volcano.
Should the Cumbre Vieja Volcano erupt in the Canary Islands, it would likely cause an earthquake. It is probable, if the earthquake were large enough, a massive landslide would occur, causing a 10-mile section of the island of La Palma to collapse into the Atlantic Ocean. Scientists believe this sudden addition of huge amounts of rock to the ocean would generate a mega tsunami with a wave 300 feet high heading westward at approximately 500 miles per hour. Within just over nine hours, the East Coast would be hit by this wall of water, which could extend up to 20 miles inland in flat or low lying areas.
The greater threat for Maine lies in the Puerto Rican Trench, an active fault area. An earthquake with a magnitude of 7 or greater on the Richter scale occurring in the Trench could produce a tsunami three- to six-feet high hitting the Maine coast five to eight hours later.
According to a scientific model constructed by the Charles Mader Consulting firm in 2001, if a three-meter (about 10 feet) tsunami arrived in the Gulf of Maine, the following would probably occur:
• “[Will] likely result in a series of smaller tsunami waves that approach the Maine coast from different directions and with different arrival times.
• “Tidal range would play a role in the severity of impacts of a tsunami wave. The tide ranges anywhere from about 9 feet in Kittery to near 20 feet in Eastport.
• “Because of the natural complexity of Maine’s coast, effects would be different from place to place. Along the outer rocky coast the effect would be similar to that of northeast storm waves at high tide that erode the soil horizon along the shore and damage piers and wharves ... with coastal flooding and structural damage to low-lying properties. Along some inner bays and estuaries that narrow in width inland, flooding would be amplified as the wave is confined to a more narrow space. In 1976 a storm surge traveled up the Penobscot River and rapidly flooded downtown Bangor with 10 feet of water [and] is the closest analog of a tsunami the Maine coast has experienced in the last century.”
The Maine coast has been the victim of tsunamis in the recent past. One example is the Boothbay Harbor tsunami of 2008. Eyewitness accounts reported that the harbor floor suddenly filled with rushing water about an hour before low tide. In 15 minutes the water rose 12 feet, then receded. This occurred three times, ripping apart docks and splitting wooden pilings. Witnesses said the water disappeared from the Harbor and then came rushing back in. This is common in tsunami events.
The CodeRED System delivers customized messages via cell phone, email, text, or voice mail. Entering your information into the system is easy and takes about five minutes. For more information, and to register, visit http://sagcounty.com/sag_emergency_management.html.