Tsunamis are often incorrectly referred to as tidal waves, but a tsunami is actually a series of waves that can travel at speeds averaging 450 (and up to 600) miles per hour in the open ocean. In the open ocean, tsunamis would not be felt by ships because the wavelength would be hundreds of miles long, with amplitude of only a few feet. This would also make them unnoticeable from the air. As the waves approach the coast, their speed decreases and their amplitude increases. Unusual wave heights have been known to be over 100 feet high. However, waves that are 10 to 20 feet high can be very destructive and cause many deaths or injuries.
Tsunamis are most often generated by earthquake-induced movement of the ocean floor. Landslides, volcanic eruptions, and even meteorites can also generate a tsunami. If a major earthquake is felt, a tsunami could reach the beach in a few minutes, even before a warning is issued. Areas at greatest risk are less than 25 feet above sea level and within one mile of the shoreline. Most deaths caused by a tsunami are because of drowning.
Two plate systems in the Atlantic Ocean are of concern to officials along the East Coast: one off the coast of Europe and Africa and the other north of the island of Puerto Rico. Both have the potential to cause Tsunamis that could affect our coastline.
In 1886, an earthquake struck the downtown Charleston area. It is reported that this earthquake caused minor tsunamis along the East Coast of the United States.
Know the height of your street above sea level and the distance of your street from the coast. Evacuation orders may be based on these numbers.
Because tsunamis can be caused by an underwater disturbance or an earthquake, people living along the coast should consider an earthquake or a sizable ground rumbling as a warning signal. A noticeable rapid rise or fall in coastal waters is also a sign that a tsunami is approaching.
Make sure all family members know how to respond to a tsunami, especially if you live on a barrier island or near a coastal water way.
In the open, stay away from buildings, trees, telephone and electrical lines, overpasses, or elevated expressways.
Teach children how and when to call 9-1-1 and which radio station to tune to for emergency information.
In case family members are separated from one another during an earthquake (a real possibility during the day when adults are at work and children are at school), develop a plan for reuniting after the disaster.
Ask an out-of-state relative or friend to serve as the "family contact." After a disaster, it's often easier to call long distance. Make sure everyone in the family knows the name, address and phone number of the contact person.
Mitigation includes any activities that prevent an emergency, reduce the chance of an emergency happening, or lessen the damaging effects of unavoidable emergencies. Investing in preventive mitigation steps now such as repairing deep plaster cracks in ceilings and foundations, anchoring overhead lighting fixtures to the ceiling and following local seismic building standards, will help reduce the impact of earthquakes and tsunamis in the future. For more information on mitigation, contact the Emergency Management Department.
Be ready to evacuate if asked to do so. If you hear an official tsunami warning or detect signs of a tsunami, evacuate at once. Climb to higher ground. A tsunami warning is issued when authorities are certain that a tsunami threat exists.
Never go down to the beach to watch a tsunami come in. If you can see the wave, you are too close to escape it.
A tsunami is a series of waves. Do not assume that one wave means that the danger is over. The next wave may be larger than the first one. Stay out of the area.
Stay tuned to a battery-Ã‚Âoperated radio for the latest emergency information.
Help injured or trapped persons.
Give first aid where appropriate. Do not move seriously injured persons unless they are in immediate danger of further injury. Call for help.
Remember to help your neighÃƒâ€šÃ‚Âbors who may require special assistance - infants, elderly people, and people with disabilities.
Stay out of damaged buildings. Return home only when auÃ‚Âthorities say it is safe.
Enter home with caution.
Use a flashlight when entering damaged buildings. Check for electrical shorts and live wires. Do not use any appliances or lights until an electrician has checked the electrical system.
Open windows and doors to help dry the building.
Shovel mud while it is still moist to give walls and floors an opportunity to dry.
Check food supplies and test drinking water.
Fresh food that has come in contact with flood waters may be contaminated and should be thrown out. Have tap water tested by the local health department.
When disaster strikes, people everywhere want to help those in need. To ensure that this compassion and generosity are put to good use, the media can highlight these facts:
City of Charleston
City of Folly Beach
City of North Charleston
City of Isle of Palms
Town of Awendaw
Town of Hollywood
Town of James Island
Town of Kiawah Island
Town of Lincolnville
Town of McClellanville
Town of Meggett
Town of Mount Pleasant
Town of Ravenel
Town of Rockville
Town of Seabrook Island
Town of Sullivan's Island
E-mail your comments or questions about this site to
Report technical problems with this site to firstname.lastname@example.org
This is the official web site for Charleston County Government.
Copyright © 2000-2019, Charleston County, South Carolina. All rights reserved.