IOWave Tsunami Exercise

Regular exercises are important for maintaining staff readiness for the real event. This is especially true for tsunamis, which are infrequent but require rapid response when they occur.

Indian Ocean-wide tsunami exercises (IOWave) are effective tools for evaluating the readiness of the end-to-end Indian Ocean Tsunami Warning and Mitigations System (IOTWMS) and for identifying changes that can improve its effectiveness.

The pre-exercise planning and post-exercise evaluation process is as important as the actual exercise, because it brings together all stakeholders to closely coordinate their actions. Every Indian Ocean country is encouraged to participate.


The Next IOWave Tsunami Exercise

Exercise IOWave23 will include four tsunami scenarios held over a three-week period during 4-25 October 2023. The exercise will simulate Indian Ocean countries being put in a tsunami warning situation and require the National Tsunami Warning Centre (NTWC) and the National and/or Local Disaster Management Offices (NDMOs/LDMOs) in each country to implement their standard operating procedures. The exercise will test preparedness for responding to tsunamis generated by seismic and non-seismic (volcanic) events.

In addition to testing standard operating procedures and communication links at all levels of the warning chain, a primary objective of Exercise IOWave23 is to enhance tsunami preparedness at community level. To this end, the exercise will provide an opportunity for Member States to test the UNESCO-IOC Tsunami Ready programme indicators in communities. All IOTWMS Member States are strongly encouraged to conduct the IOWave23 exercise to community level and to test the twelve Tsunami Ready indicators in the areas of tsunami assessment, preparedness, and response.

The occurrence of non-seismic and complex source tsunamis (i.e., 2018 Sulawesi, Indonesia; 2018 Anak Krakatau, Indonesia; 2022 Hunga Tonga–Hunga Haʻapai, Tonga), have served as a reminder that not all tsunamis are generated by undersea earthquakes. For the first time, the IOWave exercise will test the response to a tsunami generated by a non-seismic tsunami source. Specifically, scenario 3 will simulate a volcanic eruption in the Southern Ocean resulting in a regional tsunami event.

Exercise IOWave23 will comprise four scenarios with simulated tsunami waves travelling across the Indian Ocean basin. Member States are invited to participate in one or more events, which will run in real time.

  • Scenario 1 starting at 04:00 UTC on Wednesday 4th October 2023: Magnitude ~9 earthquake in the Andaman trench off the west coast of Nicobar Islands, India.
  • Scenario 2 starting at 06:00 UTC on Wednesday 11th October 2023: Magnitude ~9 earthquake in the Makran trench of the North-West Indian Ocean.
  • Scenario 3 starting at 06:00 UTC (eruption at 05:00 UTC) on Wednesday 18th October 2023: Volcanic eruption of Heard Island in the Kerguelen Islands Region.
  • Scenario 4 starting at 02:00 UTC on Wednesday 25th October 2023: Magnitude ~9 earthquake in the Java trench to the south of Java, Indonesia.

Following the exercise, countries will complete an online evaluation on their national response, which will inform the exercise report. Lessons learnt will be discussed in the post-Exercise IOWave23 workshop to be held online during November 2023 (to be confirmed).

Please follow the iowave23 X (previously twitter):  @iowave23

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