EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Setting up of the Indian Tsunami Early Warning System (ITEWS): National and International Interactions for the Success of ITEWS

Harsh Gupta
Harsh Gupta
  • CSIR-National Geophysical Research Institute, Seismology, Hyderabad-50007, India (

The 26 December 2004 Sumatra earthquake of Mw 9.2 and the resultant tsunami that claimed over 2,50,000 human lives is probably the most destructive natural disaster of the 21st Century so far. Although the science of tsunami warning had advanced sufficiently by that time, with several tsunami warning centers operating in various oceans, no such system existed for the Indian Ocean. Here we present the discussions and interactions held in India and globally to convince setting up of ITEWS. False tsunami alarms subsequent to 26 December 2004 earthquake had developed a sense of scientific disbelief in the public and to a certain extent in Government of India. We demonstrated to the national and international community that there are only two stretches of faults that could host tsunamigenic earthquakes as far as the India Ocean is concerned. These are: 1) a stretch of some 4000 km of a fault segment extending from Sumatra to Andaman Islands and 2) an area of about 500 km radius off the Makaran Coast in the Arabian Sea. And if we cover these two areas with ocean bottom pressure recorders, the problem of false alarms would be reduced to a large- extant. This plan was finally agreed to and necessary financial, logistic and technical support was made available. The setting up of the ITEWS started in middle 2005 and was completed in August 2007. It has performed very efficiently since then. Over the past ~ 8 years, it monitored ~ 500 M ≥ 6.5 and provided advisories. As against the requirement placed by IOC of issuing an advisory in 10 to 15 minutes time, ITEWS has been doing it in ~ 8 minutes. Since its inception in 2007, no false alarm has been issued and it is rated among the best in the world.

IOC has designated ITEWS as the Regional Tsunami advisory Provider (TSP) Indian Ocean Regional Tsunami Center.

How to cite: Gupta, H.: Setting up of the Indian Tsunami Early Warning System (ITEWS): National and International Interactions for the Success of ITEWS, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-4479,, 2020

Comments on the presentation

AC: Author Comment | CC: Community Comment | Report abuse

Presentation version 1 – uploaded on 30 Apr 2020
  • CC1: Comment on EGU2020-4479, Alik Ismail-Zadeh, 04 May 2020

    Dear Harsh, Thank you for the excellent presentation of your paper and congratulations on the success of ITEWS. My question is about the system of alerting the population: how it is developed in India and how well is ITEWS alerts are communiced to neighbouring countries? Thanks.

    • AC1: Reply to CC1, Harsh Gupta, 04 May 2020

      Dear Alik, Thanks for your very important question. Within India, we have a system for fishermen, advising them in real-time, where the catch would be good. This is done through SMS on their cell phones on the hour every hour basis. Since the travel time from the two established tsunami sources in the Indian Ocean to mainland India is more than 2 hours, this works quite well. Besides, on the east and west coasts of India, there are electronic boards placed at intervals of ~ 2 km. These boards have fishing ground information continuously displayed all the time. After setting up of ITEWS in 2007, additional info about a tsunami is provided on these electronic boards, soon after (say within 10 minutes) the occurrence of the tsunamigenic earthquake. Moreover, the radio broadcast is made which is very popular in the coastal areas.

      India issues alert to all the Indian Ocean rim countries, providing the approximate time of arrival of the tsunami on the corresponding coast and its height, under an agreement, within 10 minutes of the occurrence of the tsunamigenic earthquake.