Transforming Tsunami Science: Lessons from the 2004 Indian Ocean Earthquake

Sub : Geo

Sec: Geomorphology

Why in News

The year 2024 marks two decades since the catastrophic 2004 Indian Ocean earthquake and tsunami, one of the deadliest natural disasters in recorded history. This anniversary provides an opportunity to reflect on advancements in tsunami science, disaster preparedness, and mitigation efforts inspired by this event.

2004 Indian Ocean Earthquake:

The earthquake originated 30 km below the ocean floor in the Sunda Trench, where the Indo-Australian plate subducts beneath the Burma microplate.
It tore through a 1,300 km stretch from Sumatra to the Coco Islands.
The earthquake was the third largest globally since 1900.
Affected Countries: Indonesia, India, Bangladesh, Malaysia, the Maldives, Myanmar, Sri Lanka, Thailand, and others faced significant damage.
Approximately 227,000 people lost their lives, and 1.7 million were displaced.
Prior tsunamis in the region were smaller in scale, such as those caused by an 1881 earthquake near Car Nicobar and the 1883 Krakatoa explosion.

About Tsunami:

Tsunami (a Japanese word that means “harbour wave”) is a series of giant ocean waves caused by earthquakes or volcanic eruptions under the ocean.
When an earthquake occurs under the ocean, a large chunk of the ocean floor can suddenly move upward or downward, leading to a sudden displacement of a large volume of water, thereby causing tsunami waves.
Similarly, the lava flowing out of the volcano displaces the water around it and that water can become a large wave.
Other factors that can cause tsunamis are- landslides, meteorites and asteroid impacts.

Characteristics:

The formation of a tsunami can depend on a host of factors, including the shape of the ocean floor, and the earthquake’s distance and direction.
Tsunami waves can be hundreds of feet tall and can travel as fast as jet planes over deep waters while slowing down when reaching shallow waters.
Not all earthquakes or volcanic eruptions lead to tsunamis.
Tsunamis generated in the open ocean appear to be only small waves.
Tsunami waves become dangerous only when they get close to the coast.
An increase in wave amplitude results in “shoaling” when waves, including tsunamis, run from deep to shallow water. This is significant in coastal regions. This phenomenon occurs because of the force from the seabed as it becomes shallower. This slows down the wave: the shallower the water, the slower the wave.

Tsunami Warning Systems

Indian Tsunami Early Warning Centre (ITEWC): Established in 2007, it operates under the Ministry of Earth Sciences at INCOIS, Hyderabad.
Monitors through seismological stations, bottom pressure recorders, and tidal stations.
Issues tsunami alerts within 10 minutes of detecting potential earthquakes.
India became the fifth country to develop advanced tsunami warning capabilities, joining the U.S., Japan, Chile, and Australia.

Global Vulnerabilities:

Makran Coast: Potentially threatens India’s west coast, including Mumbai.
Myanmar Coast: Poses risks to Northern Indian Ocean regions.
Kalpakkam Case Study: The 2004 tsunami caused a shutdown at the Kalpakkam nuclear plant, which resumed operations without releasing radioactive material.
Lessons from Fukushima (2011): Reinforced the need for stringent safety protocols, as radiation leaks can have far-reaching consequences.