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Tsunamis: development of coastal limits

Tsunamis: development of coastal limits

By Marcos Sommer

Since December 2004, the 26th of each month has been marked in the collective calendar that humans have reserved for tragedies that are impossible to forget. In Southeast Asia, that calendar has now been one year since an unprecedented tsunami hit.

Tsunamis: Development ignored the Coastal Ecological limits.

  • Over the last few years of free-market-led globalization, respect for the vulnerability of coastal and marine ecosystems has been sacrificed for the construction of hotels, industrial-scale shrimp farms, and refineries. Mangroves and coral reefs have been relentlessly destroyed, removing natural protective barriers against storms, cyclones, hurricanes and tsunamis. It is not without attention that George W. Bush and Tony Blair seemed lethargic the first week of the tragedy in December 2004, as if the devastating work of nature did not concern them or as if they were surprised that something so far from their will had caused a catastrophe that had no relation to their decisions: as if habit had accustomed them to think that only they can be the engine of so many deaths and suffering.


The coastal areas of India, Sri Lanka, Thailand, Malaysia, Somalia, Maldives and Bangladesh were affected by the earthquake whose epicenter was located on the west coast of Sumatra, 1,605 kilometers from Jakarta and 4 kilometers deep.

Since December 2004, the 26th of each month has been marked in the collective calendar that humans have reserved for tragedies that are impossible to forget. In Southeast Asia, this calendar has already added a year since an unprecedented tsunami crashed, in a journey of thousands of kilometers, against the coasts of seven countries and became a planetary tragedy because it affected not only Asians but also large number of western tourists. When the giant waves receded to the shore, they had left a trail of almost 300,000 corpses, a million injured or permanently disabled, millions of displaced people who have been left homeless, landless and jobless and material devastation of devastating dimensions.

The life of man on the planet develops in a context of permanent interaction with the natural system. A natural disaster is caused by an inappropriate relationship between people and that system. Natural hazards are extreme natural events perceived by man, threatening his life and property. The natural disaster is the materialization of the perceived risk. It is man who, by occupying risk areas, establishes the potential damage of a natural event. Consequently, an extreme natural event acquires the connotation of a disaster only when man and / or his activities and his assets are involved.

Almost two-thirds of the world's population, approximately 3.7 billion, live in coastal areas. It is estimated that this figure will increase by the year 2,025, reaching 75 percent of the planet's population, that is to say that in that year, 6.4 billion people will inhabit the coastal belt. These regions are home to a large part of the most productive and biodiverse ecosystems.

Of all the destructive natural risks that man must face, tsunamis are one of the cruelest and the most implacable due to their speed and unpredictable violence. They are concentrated in risk areas, these are very numerous and sometimes they seem asleep for a long time. Science can be a means of "taming" them to better limit them, but not to eradicate them.

The December 2004 Indian Ocean earthquake was an underwater earthquake with a magnitude of 9.0 on the Richter scale that shook the eastern Indian Ocean. This earthquake, which originated in the sea near the northern coast of the Indonesian island of Sumatra, triggered several massive tsunamis that affected coastal areas of eight Asian countries and killed more than 300,000 people. This was the fifth strongest earthquake in modern history (since recorded with seismographs).

A tsunami, (from the Japanese, literally great wave in the harbor) is a wave or a group of waves that occur in the water when they are pushed by a great force that makes them move vertically, so that the ocean is propelled out of its normal balance, when that immense body of water tries to regain its balance, waves are generated.

The size of the tsunami will be determined by the magnitude of the vertical deformation of the seabed. Not all earthquakes generate tsunamis, but only those of considerable magnitude, which occur under the seabed that are capable of deforming it.

Tsunamis can be triggered by volcanic eruptions, earthquakes, meteorites, landslides, or explosions. The energy of a tsunami is constant and depends on its height and its speed. Due to this, when the wave approaches the ground, its height increases while its speed decreases (50 km / h). The waves travel at high speeds (700 km / h, similar to an airline jet), being almost imperceptible when crossing deep water, but their height can grow half a meter or more than 30 meters when they reach the shoreline, hence they are not perceptible on the high seas. This phenomenon is formed


Tsunamis are waves in the water or marine seismic waves, caused by a sudden large-scale movement of the seabed, generally due to earthquakes and, on very rare occasions, to landslides, volcanic eruptions or man-made explosions.

by several waves that arrive separated from each other by about 15 or 20 minutes, and what makes it very dangerous is that the first one that arrives is very similar to the normal ones. Normally the first manifestation of the tsunami is a retreat of a few tens or hundreds of meters from the sea and after about 5 to 15 minutes, the resounding advance of the sea takes place, which can penetrate kilometers of the coastline.

Tsunamis cause great destruction on the affected islands and coasts. This “tsunami” phenomenon is often confused with the term “tsunami”, but the latter are related to an oceanic imbalance produced by the gravitational attraction exerted by the planets and especially the moon on the earth. Of all natural disasters, tsunamis are among the most terrifying and complex phenomena, responsible for the great loss of life and extensive destruction of property. Massive destruction of coastal communities has occurred throughout the world by such great waves since the beginning of recorded history written to 1,480 BC, when the Minoan civilization in the Eastern Mediterranean was wiped out by the great tsunami waves generated by the volcanic explosion of the island of Santoriu.

Japan, which has one of the most populated coastal regions in the world, has a long history of seismic activities and tsunamis. Tsunamis with their destructive force have also been recorded in Alaska, the Hawaiian Islands, and South America.

While any ocean can experience a tsunami, it is most common in the Pacific Ocean, the margins of which are most commonly the site of earthquakes of considerable magnitude. The area located along the coast of the Pacific Ocean is part of the so-called “Pacific Circle of Fire” (especially the coasts of Chile, Peru and Japan) which is made up of a series of volcanoes linked to tectonic faults on the coast and on the seabed, mostly active, which causes permanent seismic and volcanic activity throughout the Andean area, determining a great vulnerability of the coastal areas and the population that lives there, in the face of these events. In addition, the type of fault that occurs between the Nazca and South American plates, called subduction, that is, one plate moves under the other, makes the deformity of the seabed more conducive and ultimately tsunamis.


“Pacific Circle of Fire” (made up of a series of volcanoes linked to tectonic faults on the coast and on the seabed.

A natural disaster such as a tsunami is a dangerous event that causes environmental effects or alterations (physical, biological, social, economic) of such magnitude that ecosystems and / or society are not able to withstand without seeing their basic functional elements destroyed. and its dynamic balances.

Despite its importance, both as a source of food, for leisure and as a climatic factor, surprisingly little is still known about the structure and functioning of the marine ecosystem. Our understanding and predictability of the effect of human activity on ecosystems is also very poor despite its great impact on the marine environment and its biodiversity, especially due to pollution from industrial and domestic sources in rivers, coastal waters and the sea. Other aggressions are the spills of ships that clean their fuel tanks at sea, shipwrecks and overexploitation of coastal areas. The introduction of non-native species into new marine environments can also lead to environmental problems. All of this is increasingly causing the disturbance and pollution of our seas with negative effects on marine habitats and the fauna and flora that they shelter.

The environmental vulnerability of the Indian Ocean implies evaluating the susceptibility or resistance of that area to disasters caused by Tsunami. The resilience or buffering capacity of a region is largely related to the provision of environmental services from the natural resources it possesses, such as well-preserved ecosystems, particularly beaches, forests, watersheds, etc.

Human intervention can increase the frequency and severity of natural disasters, and can also create natural hazards where they did not exist before. This can happen by introducing modifications in the coastal environment through the construction of works, the inappropriate management and use of it or by the destruction of the ecosystem, without considering the processes and geophysical dynamics and the existing ecological relationships (which can naturally mitigate the impacts of an extreme natural event). In this sense, the prevailing development model in the Indian Ocean region has not given sufficient importance to the application of policies and instruments of land use planning, under environmental sustainability criteria that prevent this type of risk.

Since the 1980s, the coastal regions of Asia have been encroached upon by large shrimp farming companies that have implemented environmentally destructive aquaculture on their shores. Shrimp farming, which has exceeded 8 billion tonnes in 2000, has wreaked havoc on delicate ecosystems. The 'start and go' industries, as the FAO (Food and Agriculture Organization of the United Nations) have already denounced, are being financed largely by the World Bank, and about 72% of shrimp farms they are found in Asia. The expansion of these shrimp farms has been at the expense of tropical mangroves - which are among the most important ecosystems in the world. Each acre of destroyed mangrove causes an approximate loss of 676 pounds of fish catch. The mangrove marshes have been a natural protection of the coastal regions against high tides, against the impact of cyclones and constitute the nursery for three-quarters of the commercial fish species that develop part of their life cycle in wetlands of the mangrove. Mangroves, in any case, are being one of the most threatened habitats in the world, but instead of regenerating those wetlands, bad economic policies have only accelerated their disappearance.

In the last 15 years, shrimp farming has increased tenfold and is now a $ 9 billion industry. Shrimp consumption in North America, Japan and Western Europe is estimated to have increased by 300 percent in the last ten years. The massive destruction, in only 11 Asian countries, caused by the December 26 tsunami, exceeds by several times the economic benefits that the shrimp industry claims to have achieved.

Since the 1960s, for example, aquaculture and other industrial activities in Thailand have caused the disappearance of more than 65,000 hectares of mangroves. In Indonesia, Java has lost 70 percent of its own, Sulawesi 49 percent and Sumatra 36%. So when the tsunami hit in all its fury, logging companies in Aceh province were fully engaged in cutting mangroves for export to Malaysia and Singapore.

In India, the mangrove area has shrunk to less than a third of its original size in the last three decades. Between 1963 and 1977 India has destroyed about 50 percent of its marshes. Local communities have been forced to abandon them to allow shrimp farms to be established.

The maximum life cycle of a hatchery is two to five years. Once elapsed, the deposits are abandoned, leaving toxic waste, the destroyed ecosystem and displaced human communities, with the annihilation of their livelihoods. Hatcheries are started at the expense of natural ecosystems including mangroves. Then, the complete cycle is repeated in another virgin area of ​​the coast. It is estimated that the economic losses produced by shrimp farms are equal to five times their potential profits.

The importance of environmental vulnerability to extreme Tsunamis in the region, as a vital dimension to be considered in its future development, makes it necessary to have mechanisms to assess and consequently to reduce it, thereby strengthening the region's capacity to face this natural phenomenon, with the least economic, social and environmental loss.

The location of human activities and settlements on the coast without planning as a direct cause, together with the sustained growth of the population of Asian and African countries and the persistence of poverty situations, as intensifying effects, has increased environmental vulnerability in the region, which is dramatically manifested by a devastating effect like this Tsunami.

Human intervention on coastal ecosystems covers a spectrum of different anthropogenic impacts, ranging from:

  • Intensive mariculture.
  • Widespread coastal erosion, often exacerbated by inadequate human infrastructure.
  • Destruction of habitat, as a consequence of poorly planned construction and land use or exploitation of the sea, cause alterations to the geoform, the coastline and the pattern of currents, such as marinas, docks, breakwaters, dikes and breakwaters .
  • Loss of biodiversity, including the decline of fish populations on the coast and in the high seas, due to the deterioration of the coastal areas of spawning, feeding, refuge, reproduction and rearing of fauna species.
  • Loss of mangroves, beaches, cliffs or reefs.
  • Contamination of soil and water resources, to the extent that pollution from marine or interior sources, including landfills, moves towards the coast.
  • Unemployment and social instability due to the decline of traditional sectors or those compatible with environmental concerns.
  • Destruction of cultural heritage and dilution of the social fabric due to uncontrolled development (especially tourism).

Tourism on the coast of the Indian Ocean (Southeast Asia) has brought about substantial modifications to the populations and localities of the regions where the waves of tourism occur. These effects are socio-economic and cultural, and the most significant of them are: there is a greater need for infrastructure, with the introduction of energy, roads and access roads, airports and airstrips, ports and marinas, drinking water networks and sewerage, drinking water and water treatment plants, among others. All these large-scale works, significant costs and modifications to regional budgets, also generate significant impacts on the coastal environment.

Coastal tourist developments can cause the disappearance of feeding, refuge, reproduction and breeding sites of fauna species, such as mangroves, beaches, cliffs or reefs.

The construction of certain types of infrastructure or equipment for tourism, especially those associated with aquatic activities, cause alterations to the geoform, the coastline and the pattern of currents, such as marinas, docks, breakwaters, dikes and breakwaters. . This can bring repercussions such as the loss of beach surface, the breakdown and deterioration of infrastructure and the availability of nutrients.

The boom Tourism in the Asian and Pacific region has coincided with the destructive consequences of the growth of shrimp farming. In the last decade, tourist inflows and income have increased faster than anywhere else in the world, almost twice the rates of industrialized countries. Forecasts for 2010 indicate that the region will surpass that of America to become the second tourist area in the world, with 229 million entries. What is being advertised as a sign of spectacular economic growth hides the enormous environmental costs these countries are paying and will have to bear in the future.

In the last two decades, the coastline of the Bay of Bengal, the Arabian Sea and the Straits of Malacca in the Indian Ocean, and the southern Pacific Ocean have witnessed massive investment in tourism and hotels. Myanmar and the Maldives have suffered far fewer deaths from the tsunami because the tourism industry has so far not extended its tentacles to the pristine mangroves and coral reefs that line the coast. The large coral reefs that surround the Maldives islands have absorbed much of the force of the gigantic waves reducing the number of human losses to just over 100 deaths. Coral reefs absorb the fury of the sea as the waves crash. The tragedy, however, is that more than 70 percent of the world's coral reefs have already been destroyed.

Similarly, the Surin island chain off the western coast of Thailand have escaped terrible destruction. The surrounding ring of coral reefs was hit by the raging waves but held steady and helped break the deadly force of the tsunami. Mangroves help protect coral reefs by filtering silt that flows from land to sea. Tourism growth, be it so-called eco-tourism or leisure tourism, has decimated the mangroves and destroyed the coral reefs.

If the mangroves had remained intact, the damage from the tsunami would have been much less. Ecologists tell us that mangroves serve as double protection: the first layer of red mangroves with their flexible branches and tangled roots that hang over the coastal waters absorb the initial impact of the waves. The second layer of tall black mangroves functions as a retaining wall that resists much of the fury of the sea. In addition, mangroves absorb more carbon dioxide per square meter than oceanic phytoplankton, a key factor in global warming.

In Bangladesh (1960), a tsunami hit the coast in an area where the mangroves were intact and not a single human loss occurred. Those mangroves were later cut down and replaced by shrimp farms. In 1991, thousands of hapless people died when a tsunami of the same magnitude struck the same region. In southern India's Tamil Nadu, Pichavaram and Muthupet, which have thick mangroves, the December 26 tsunami has caused few casualties and little economic damage. Previously, the famous Bhiterkanika wetlands in Orissa (where tortoises are raised ridley) They reduced the impact of the “cyclone” that struck in October 1999, which killed more than 10,000 people and left millions homeless.

The epicenter of the killer December 26 tsunami was near Simeuleu Island in Indonesia. The death toll was significantly low simply because its inhabitants possess the traditional knowledge about the tidal waves that invariably occur after an earthquake. On the island of Nias, close to that of Simeuleu, the mangroves have served as a wall that has prevented the destruction of the people. The challenge, from there, for developed countries is to learn from technologies that have been proven over time and perfected by local communities.

Large tourism investments generate competition for the use of resources, especially with human settlements, agriculture and fishing. This can cause the depletion of resources for luxury consumption. Finally, a greater amount of waste and discharges is generated. Tourists consume more water per. capita per day and inputs of all kinds, which causes the need for more infrastructure for their treatment and final disposal.

It is essential, given the serious evidence of the socio-economic and environmental impacts of the natural disaster (Tsunami), that all the countries involved through their powers of the State assume a preponderant and effective role in disaster management, promoting their mitigation, prevention and reduction in an analytical, technical and proactive way, following as a conditioning strategy the planning for development and a more adequate, rigorous and applicable territorial ordering. This must be supported by adequate legislation and budgets.

In this sense, the following actions should be considered:

  1. Assessment of environmental vulnerability at the regional and local level. For this, it will be necessary, on the one hand, to develop appropriate methodologies for each case (according to the type of event and geographical characteristics of the affected territory, for example) and, on the other, to use geographic information systems (GIS) for the elaboration of integrated cartography on vulnerability and risks environmental. It would be advisable to prepare a series of maps showing the current environmental vulnerability of the countries of the Indian Ocean.
  2. The ecological zoning of the countries is another planning tool with great methodological advantages. It is comprehensive, it can be applied at various scales, it allows methodological adjustments, according to the site and the predominant or potentially more convenient economic sector.
  3. Strengthening of strategies for the development of land use planning plans and their implementation. These plans should consider vulnerability and risk maps, so that they constitute the main input for prevention, reconstruction and environmental emergency plans. Regional planning provides an integrative vision, which covers both sectoral and special aspects. Current trends in regional planning allow its orientation towards new development concepts, such as the vision of sustainability. In fact, the precepts of sustainable development can be understood in a better way when they are observed under the concept of region. This approach may mean the optimal approach to better reconcile tourism issues and natural disasters, within a more complex and global universe. However, the biggest problem lies in insufficient information necessary for the analysis, in geopolitical and jurisdiction problems, in the emergence of conflicts when trying to put regional issues before micro and local interests, among others.

The coastal regions are in an alarming ecological state in Asia and Africa. The explosive growth of cities, booming mass tourism, unregulated industrialization, intense agriculture and expanding aquaculture, as well as overfishing in the seas, damage the sensitive ecosystem of the coastlines. Good health and the balance of natural systems are essential to sustain life and the functioning of society. The pressures exerted by pollution, the unsustainable exploitation of the soil and the sea and the risks to biodiversity must be repaired. Reducing the impact of climate change requires adequate planning of the use of natural resources and investment in technologies to adapt. None of this is easy for Asian countries with limited resources.

In recent years a new tool for coastal planning and management has been introduced. Integrated Coastal Zone Management (ICZM) (Chapter 17 of Agenda 21 and the 1993 World Coastal Conference), a comprehensive and integrated multipurpose coastal environment-oriented instrument that aims to improve the quality of life of communities dependent on coastal resources and help coastal states achieve sustainable development on issues such as depletion of fisheries, deterioration of water quality, conflicts between coastal uses, etc. At the same time, it combines participatory processes and techniques such as zoning, access restrictions, habitat management, monitoring, and enforcement to achieve a balance between coastal uses based on joint and supported objectives, to improve living conditions, safeguard property and protection of coastal marine ecosystems.

The objectives of the Integrated Management of the Coastal Zone can be defined as follows:
1) The Integrated Management of the Coastal Zone must be subject to a political process where the challenge is based on the development, implementation and adaptation of sustainable solutions to solve problems and conflicts of use.
2) Use the best information available for planning and decision-making-management of scientific knowledge.
3) Involve all stakeholders in the development of an open, participatory and also democratic process.
4) Develop programs that have been identified in the participation processes.
5) Work at the international, national and local levels, with strong links between them.
6) Increase regional and local capacity through training programs in the short and long term.
7) Encourage feedback on activities, which requires that planning and implementation be coordinated and effective, as quickly and frequently as possible.
8) Ensure that programs are subjected to cycles of development, implementation and refinement, building on previous successes and adapting and expanding to address new or more complex issues.
9) Development and deepening of methodologies for evaluating the environmental impacts (EIA) of extreme physical events, in order to be able to estimate the magnitude of damage and losses to the natural heritage (qualitative and quantitative) and propose mitigation measures, in the face of disasters futures (Tsunami). This also makes it possible to sensitize decision-makers regarding the importance of environmental protection and proper management of natural resources as a preventive measure to mitigate impacts. The Environmental Impact Assessments (EIA) constitute a support element, so that in the prioritization of reconstruction projects, those of recovery and rehabilitation of degraded or damaged ecosystems are considered.
10) Development, strengthening, dissemination and harmonization of Tsunami monitoring and early warning models in the region.

The hypothesis that orderly development (fishing, beach, tourism, etc.) naturally results from adequate action in each sector, is largely denied in all countries where it has been applied, even if laws and regulations are adequately complied with. The dynamics of the whole is something more than the sum of the parts, and integrated management requires an overall and long-term vision, encouraging the preparation of municipal plans to zoning and ordering the territory and accepting resources and consistent rules of the game to building the new reality site by site and with local participation seem to be the key mechanisms of Integrated Coastal Management.

We currently have more than enough evidence to show that our inability to protect the marine environment will have consequences for the future of the planet and for our quality of life. Climate change, largely driven by greenhouse gas emissions, has begun to increase the average temperature, leading to frequent heat waves and an increased risk of flooding in coastal communities. Cancer chemicals are found in our blood even though they are substances that were banned many years ago.

Efforts for sustainable development are often presented as a luxury that only concerns the relatively wealthy populations of the northern hemisphere. However, the environmental and health price of not guaranteeing sustainability is so high that doing nothing is precisely the luxury we cannot afford. Por consiguiente, no cabe la menor duda de que conocemos los problemas. Entonces, ¿por qué no hacemos nada para aplicar las soluciones? Existen varias razones. Un argumento de peso contra las iniciativas a favor del desarrollo sostenibles consiste en que frena a las industrias, obligadas a competir en un mercado mundial. Otro serio obstáculo que impide lograr el objetivo del desarrollo sostenible: una exigencia real por parte de la propia sociedad. Los ciudadanos, las empresas y los gobiernos han de tener la voluntad de cambiar su comportamiento y lograr que el desarrollo sostenible sea una realidad. La exigencia de un desarrollo sostenible empieza por nosotros mismos. Debemos aprender a consumir de un modo diferente, más eficaz y con el objetivo de mejorar no solamente nuestra calidad de vista sino también la de aquellas personas que producen lo que consumimos, en todas partes del planeta. Nuestras vidas están cada vez más interrelacionadas. La mundialización implica que todos compartimos un futuro común. Tenemos la responsabilidad con las futuras generaciones de actuar ahora y sin reparos. Si no hacemos nada, cometeremos un error que jamás nos perdonarán, y con razón, nuestros hijos y los hijos de nuestros hijos.

* Dr. Marcos Sommer
Ökoteccum
G ermany


Video: Watch how the tsunami happens after an earthquake deep in the sea, watch the speed of the waves (May 2021).