Awareness and risk reduction

Il The logo of the 2018 World Tsunami Awareness Day

Miyako (Japan) the inhabitants witness from above the arrival of the second wave of the Tsunami caused by the earthquake of Valdivia (Chile) on 22 May 1960.

An illustration of a Smong information brochure

Although they may seem rare, tsunamis are among the most devastating natural disasters, affecting low and densely populated coastal areas, causing heavy human and economic losses. Over the past 100 years, more than 260,000 people have died in 59 different tsunamis. With an average of 4,600 victims per disaster, the toll has surpassed that of any natural disaster. The Mediterranean Sea, contrary to popular belief, is not immune to this kind of phenomena, and it has been calculated that 15-20% of the globally documented events occurred precisely in this basin. To date, around 130 million people live permanently along the 46,000 km of Mediterranean coasts, in addition to 230 million tourists who visit them every year. The continuous growth of coastal populations, together with the increased importance of tourism activities and the maritime economy, make it particularly important to improve tsunami risk reduction strategies.

After the catastrophic Sumatra tsunami of 2004, the UNESCO Intergovernmental Oceanographic Commission (IOC-UNESCO) has worked very hard to establish, coordinate, and improve the early warning services for tsunamis, raising awareness of the world's public opinion on actions, policies, and practices that effectively reduce exposure to the risk of such catastrophes.

Communication, understanding, preparation, and involvement of individuals and communities are recognized and valued as fundamental tools for reducing the impact of tsunamis on people's lives.

In December 2015, the United Nations General Assembly designated November 5 as World Tsunami Awareness Day ( WTAD ), organized by the United Nations Office for Disaster Risk Reduction (UNISDR) following the indications of the Sendai Framework 2015-2030 to promote a global culture of awareness of tsunami risk: being aware of risk means having more tools to understand when and how to react, making the right decisions in the shortest amount of time.

A tsunami is a complex event, which once generated can last for many hours before the situation returns to its initial state of calm. It must be remembered that tsunami waves carry a great deal of energy all along the water column, from the bottom of the sea to the surface. This large mass of moving water interacts very differently with the seabed and the coasts, compared to the waves produced by the wind or other meteorological phenomena.

Most of the citizens living in the coastal areas of the countries most historically exposed to tsunamis, such as Japan, Chile, and Indonesia, know that if they feel a strong earthquake they must immediately seek a safe shelter by moving away from the sea towards higher ground, such as mountains, hills or tall buildings in reinforced concrete. This awareness derives in part from the historical memory of previous events, handed down from generation to generation, and partly from the educational action of the institutions, in particular schools and the civil protection agencies. 

It is very important to know that a tsunami is composed of a series of waves and the first to arrive on the coasts is not always the largest and most destructive. During the recent Sulawesi tsunami of September 2018, in some affected areas the first wave had a relatively small impact, but subsequent waves, arriving almost immediately afterwards, caused enormous destruction and many of the nearly two thousand victims. Unfortunately, this dramatic event has shown that even in some areas of Indonesia awareness is not as high as in other regions.

The first "wave" may actually be the sea retreating. Numerous historical sources document that on the occasion of the Messina earthquake, in many places in Sicily before the flood there was a significant retreat of the water.

The same thing happened in some areas during the tsunami of 26 December 2004: for example, on the Thai coasts, there was an impressive retreat of the sea that uncovered the seabed for several hundred meters.

Many European tourists, who certainly had never heard of tsunamis, were on the beach and went to collect fish and shells, only to be inevitably overwhelmed by the next wave.

There are many photographic and video testimonies of this event in Phuket, Khao Lak, Kho Lanta https://www.14dd5266c70789bdc806364df4586335-gdprlock/watch?v=BAybjHCEvR0 .

Awareness of tsunamis is crucial to making quick decisions that can save lives. A very important episode occurred in this regard: during the 2004 tsunami, a 9-year-old English girl, Tilly Smith, saved the lives of over 100 people.

Shortly before, at school, they had explained to her that a tsunami could be preceded by the retreat of water: she gave the alarm immediately, allowing people to escape and get to safety by going as high as possible. This shows that simple knowledge can really make the difference between life and death.

It is precisely for this reason that after 2004, especially on the initiative of international bodies such as the IOC / UNESCO, there was intense research and planning to improve risk reduction activities. These activities did not only concern the scientific and technological aspects related to the location of earthquakes capable of generating tsunamis and early warning, but also the need for an increase in awareness.

Much work is also underway on evacuation plans and communication initiatives with the media and training in schools, to emphasize the importance of prevention and initiatives to be organized in times of peace to help communities be prepared for, understand, and cope with tsunamis. For example, the Tsunami Ready®  initiative is being implemented in different parts of the world, a program divided into stages that serves to improve the ability of communities to reduce the tsunami risk. Tsunami ready® is based on the creation and dissemination of hazard and evacuation maps at the local level, on training and awareness programs for communities and schools, on annual exercises, on the creation of centres to be activated in case of emergency and on tools for public alert dissemination.

Historical memory is important: we defend ourselves much more effectively from known and familiar events than from those of which we know nothing. Anthropological studies have shown that knowledge about natural hazards tends to be incorporated into various forms in the cultures of populations facing them. In traditional cultures this knowledge is transmitted orally from one generation to another, overcoming the problem of the weakening of historical memory, typical of modern societies.

One of the most relevant cases is that of the inhabitants of the island of Simeulue, located 60 km from the epicentre of the earthquake responsible for the 2004 Sumatra tsunami. The tsunami came fifteen minutes after the quake, but of the 78,000 people who lived on the island, only seven died.

All the others were saved because from an early age they had learned the "song of the Smong" (tsunami or chaos in the Devayan language), a traditional song composed after a catastrophic tsunami occurred in 1907 and handed down from generation to generation, which contains some very clear prescriptions on how to interpret and react to these events.