< General Studies Home Page 

Contents

• Introduction
• Causes of Tsunami
• Tsunami Detection
• Steps that we further need to take

---

Introduction

• The term Tsunami has been derived from the Japanese term ‘Tsu’ meaning harbour, and ‘nami’ meaning waves. Thus tsunami means ‘harbour waves’.
• Tsunami consist of a series of waves which rise as high as 10 meters or more. They move inland, several hundred kms causing untold disasters. These waves move at great speed and sometimes they move even 50 km/h on the coastal plains.
• 26th Dec 2004 Tsunami/Great Sumatran Andaman Earthquake / Asian Tsunami / Boxing Day Tsunami
  • An undersea earthquake occurred on Dec 26, 2004, with an epicenter off the west coast of Sumatra, Indonesia. The earthquake triggered a series of devastating Tsunamis along the coasts of most of the countries bordering the Indian Ocean. 225,000 people were killed in 11 countries.

• • The earthquake which triggered the Tsunami was of a magnitude between 9.1 to 9.3 on the Richter scale. It is second largest earthquake ever recorded on a seismograph. This earthquake lasted for about 10 minutes. It caused entire planet to vibrate as much as 1 cm and triggered other earthquakes as far as Alaska.

Causes of Tsunami

1. Earthquake of more than 6.5 on the Richter Scale, with a vertical disruption of water column
due to vertical tectonic displacement of the sea bottom along a zone of fracture in the earth’s
crust is the most important cause of Tsunami.

2. Volcanic Eruption, and submarine landslides are other reasons which may displace water and
cause it to inundate coastal region

3. Nuclear Explosion, fall of large celestial bodies (like asteroid, meteorites, comets etc can also cause Tsunami)

Tsunami Detection

i. Different Ways to detect Tsunamis – Coastal tidal gauges, Satellite technologies; deep ocean assessment and report (using pressure changes)

ii. State Preparedness Measure Before Tsunami

• Hazard Mapping: Identify Tsunami prone areas
• Establishment of Early Warning System
• Educate people in these regions about Tsunamis – inform them about the evacuation routes in case a Tsunami hits the coast.
• Mock Evacuation drills should be conducted periodically so that people are aware of it
• Capacity Building to deal with Tsunami disaster
• Provisions for sufficient provisions during emergency
• Land use planning and engineering solutions
• Increasing plant biodiversity along the coast.

iii. Preparedness by citizens

• Live at safe distance from coastline; in elevated houses; well managed drainage system; easy access to information system like TV radio etc; following SOP during Tsunami.

iv. Tsunami Response

• People on Land: After warning sound move to safer places with cattles (top floor of the multi-storied buildings); stay away from rivers that flow into the oceans; Listen to radio and TV for updates regularly.
• People on Sea: Don’t return to coast; if time is available move to deeper waters;
• Government: Search and rescue; basic services like water, first aid etc.

Nodal Agency for Tsunami Forecast: Indian National Center for Oceanic Information Services (INCOIS)

Steps taken by India Since 2004 Tsunami: The 2004 Tsunami highlighted the clear lack of preparedness about Tsunamis all over the world. None of the affected countries, including India had any system for early warning of such Tsunamis, nor was there any plan for emergency response. Learning a lesson from 2004 Tsunami, GoI have taken a number of steps:

1. Early Warning System: GoI has established the state-of-art India Tsunami Early Warning Centre (ITEWC) (operational since 2007) at the Indian National Centre for Ocean Information Services (INCOIS) as an autonomous body under Ministry of Earth Sciences.

2. INCOIS has extended GIS-based 3D protocol on Tsunami warning to all vulnerable areas in the
country with new methodologies and improved warning procedures.

3. Strengthening Tsunami Research has been a key focus of GoI since 2004.

4. National Disaster Management Guidelines for management of Tsunami, 2010

5. Regular Mock Drills are conducted by NDMA, INCOIS and Ministry of Home Affairs

• These exercises help familiarize participants with their responsibilities, actions required and
  further help them evaluate the Standard Operating Procedure (SOP) for Tsunami warnings.

6. Awareness generation programs in coastal area is also conducted regularly since 2004.

Steps that we further need to take

• Improve EWS: Advanced technology such as Artificial Intelligence and Machine learning should be incorporated to improve the Early Warning System in the country.
• Increased International Collaboration in real time monitoring will help support each other during emergencies.
  • BIMSTEC can play a very important role in promoting this collaboration in Bay of Bengal region.
• Regular training and Capacity building through workshops, drills etc. can help us avoid the 2004 scenario.
• Land use planning is one area which has been mostly ignored.
  • There is a requirement of more vegetation cover in coastal region, but various studies have shown that mangrove cover has gone down over the years.
• Removing the limitations of India’s disaster management institutional framework