Tsunami

what is tsunami ?

Tsunamis are ocean waves caused by large earthquakes and landslides that occur near or under the ocean. Scientists do not use the term “tidal wave” because these waves are not caused by tides. Tsunami waves are unlike typical ocean waves generated by wind and storms. When tsunamis approach shore, the behave like a very fast moving tide that extends far inland. A rule of thumb is that if you see the tsunami, it is too late to out run it. Most tsunamis do not “break” like the curling, wind-generated waves popular with surfers. Even “small” tsunamis (for example, 6 feet in height) are associated with extremely strong currents, capable of knocking someone off their feet.

Because of complex interactions with the coast, tsunami waves can persist for many hours. As with many natural phenomena, tsunamis can range in size from micro-tsunamis detectable only by sensitive instruments on the ocean floor to mega-tsunamis that can affect the coastlines of entire oceans, as with the Indian Ocean tsunami of 2004. If you hear a tsunami warning or if you feel strong shaking at the coast or very unusual wave activity (e.g., the sea withdrawing far from shore), it is important to move to high ground and stay away from the coast until wave activity has subsided (usually several hours to days).

History of tsunami in America

The west coasts of North and South America, particularly the Pacific coasts, are more prone to experiencing tsunamis due to their proximity to tectonic plate boundaries. Here are some historical instances of tsunamis in the Americas:

1. Alaska (1964): The Great Alaska Earthquake, which occurred on March 27, 1964, is the most powerful earthquake recorded in North American history. The earthquake, with a magnitude of 9.2, triggered a series of tsunamis that affected coastal areas in Alaska, British Columbia, and the U.S. West Coast. The tsunamis caused significant damage and loss of life.
2. Hawaii (1946 and 1960):
   • In 1946, a tsunami generated by an earthquake in the Aleutian Islands struck the Hawaiian Islands, causing damage and fatalities.
   • In 1960, the Chilean earthquake, one of the strongest earthquakes ever recorded, generated a tsunami that affected the entire Pacific Ocean, including Hawaii. This event resulted in damage and loss of life in Hawaii.
3. Oregon and California (1964): The 1964 Alaska earthquake and subsequent tsunamis also affected the coasts of Oregon and California. While the impact was less severe compared to Alaska, it highlighted the potential for long-distance tsunami propagation.
4. Chile (2010): The magnitude 8.8 earthquake that struck off the coast of central Chile on February 27, 2010, generated a tsunami that affected coastal areas in Chile and prompted tsunami warnings across the Pacific, including the U.S. West Coast and Hawaii.
5. Cascadia Subduction Zone: The Cascadia Subduction Zone off the Pacific Northwest coast poses a significant tsunami risk. Historical evidence, including geological studies and Native American oral traditions, suggests that large earthquakes and tsunamis have occurred in this region in the past.

While these are some examples, it’s important to note that the risk of tsunamis varies along different coastlines, and preparedness measures, including early warning systems, evacuation plans, and public education, are crucial for minimizing the impact of these events.

what should I do ,if tsunami comes

If you find yourself in an area that is at risk of a tsunami, it’s crucial to have a plan in place to ensure your safety. Here are some general guidelines on what to do if a tsunami is approaching:

Before a Tsunami:

1. Stay Informed:
   • Be aware of your surroundings and know if you are in a tsunami-prone area.
   • Stay informed about local emergency plans, evacuation routes, and the location of higher ground.
2. Have an Emergency Kit:
   • Prepare an emergency kit with essentials such as water, non-perishable food, medications, first aid supplies, important documents, and a flashlight.
3. Create a Family Emergency Plan:
   • Establish a family emergency plan that includes meeting points and communication methods.
   • Practice evacuation routes with your family.

During a Tsunami Warning:

1. Evacuate to Higher Ground:
   • If you receive a tsunami warning, do not wait for official instructions to evacuate. Head to higher ground immediately.
   • Move inland and to elevated areas, as tsunamis can inundate coastal areas.
2. Follow Official Instructions:
   • Listen to local authorities, emergency alerts, and weather updates for the latest information and instructions.
   • Follow evacuation routes designated by local authorities.
3. Avoid the Coastline:
   • Stay away from beaches, coastal areas, and low-lying regions.
   • Do not return to the coast until authorities declare it safe to do so.

After the Tsunami:

1. Wait for Official Clearance:
   • Do not return to the affected areas until authorities provide clearance.
   • Be cautious of potential aftershocks, which can trigger additional tsunamis.
2. Check for Injuries:
   • Check yourself and others for injuries and administer first aid as needed.
   • Seek medical attention for serious injuries.
3. Be Wary of Damaged Infrastructure:
   • Be cautious of damaged infrastructure, debris, and potential hazards in the aftermath of a tsunami.
4. Stay Informed:
   • Continue to listen to official updates and instructions for ongoing safety information.

Remember that tsunamis can be extremely dangerous, and it’s crucial to take immediate action if a warning is issued. Being prepared and having a plan in place can significantly improve your chances of staying safe during a tsunami event.

Tsunami history in the world

Tsunamis have occurred throughout history, triggered by various geological events such as underwater earthquakes, volcanic eruptions, and landslides. Here are some notable historical tsunamis:

1. Hōei Earthquake, Japan (1707): The Hōei earthquake struck Japan in 1707 and is associated with a tsunami. The earthquake and resulting tsunami caused widespread damage and impacted the coastline of the Nankaido region.
2. Krakatoa, Indonesia (1883): The eruption of the Krakatoa volcano in 1883 triggered a series of tsunamis. The explosion itself generated enormous waves that reached as far as the coasts of Java and Sumatra, causing significant loss of life.
3. Sanriku, Japan (1896): The Meiji-Sanriku earthquake and tsunami occurred off the coast of Japan in 1896. The tsunami waves reached heights of up to 38 meters (125 feet) and resulted in the deaths of thousands of people along the Sanriku coast.
4. Chile (1960): The Great Chilean Earthquake, the most powerful earthquake ever recorded, occurred on May 22, 1960. The earthquake triggered a tsunami that affected coastal areas across the Pacific Ocean, causing destruction and loss of life.
5. Indian Ocean (2004): The Indian Ocean tsunami on December 26, 2004, was one of the deadliest natural disasters in recorded history. Triggered by a massive undersea earthquake off the coast of Sumatra, Indonesia, the tsunami affected multiple countries bordering the Indian Ocean, causing widespread devastation and resulting in over 230,000 deaths.
6. Tohoku, Japan (2011): The Tōhoku earthquake and tsunami occurred on March 11, 2011. The earthquake triggered a powerful tsunami with waves exceeding 130 feet (40 meters), causing significant damage and leading to the Fukushima Daiichi nuclear disaster.

These historical events highlight the destructive potential of tsunamis and the importance of understanding and preparing for such natural disasters. Today, many coastal regions have early warning systems and evacuation plans in place to mitigate the impact of tsunamis.