Ratih Fitria Putri



Tuesday, April 13, 2010

LAND DEGRADATION PROCESS


I. INTRODUCTION

To facilitate understanding of the geo-physical degradation processes in order to Basics Course Environmental Impact Analysis, is more obvious when traced from the nature of word processing; degradation; and geo-physical may be withdrawn prior to the proper meaning. The process is a way, change / change, or how to change, how to change something from one state to another than its original state. Degradation comes from Degradation or degrade, which means decreasing a level (grade) of something the state, condition, quality, or quantity. While the geo-physical aspects of the environment is one aspect in addition biotis and social aspects of economic and social culture. Thus is the process of geo-physical degradation, none other than the way, change, change reduced levels of state, condition, quality, or quantity of geo-physical aspects of the environment as a result of the development.


The definition is no different from understanding the negative impacts of development, because environmental impacts (Act No. RI. 23, 1997, Article 1, paragraph 20), is the effect of changes in the environment caused by a business and / or activity. Nevertheless in the analysis of the environmental impacts should be noted that in addition to understanding the environmental impacts, as noted above, it should be understood terms of major and significant impact (PP No. 27 Year 1999, Article 1, paragraph 2) is to change the very basic environmental caused by a business and / or activity. In talks geo-physical degradation process of course will not achieve greater impact conversation and important, but at least until the change of environment or environmental impacts.

Environment (UURI No. 23 Year 1997 article 1 paragraph 1) is a unit of space with all the objects, resources, circumstances, and living creatures, including humans and their behavior, which affect the sustainability of livelihood and welfare of human beings and other living creatures life. The meaning of objects is an aspect of state power and geo-physical environment which consists of environmental components such as climate, physiography, hydrology, hidrooseanografi, land space and land. The meaning of life other than human beings are aspects of the environment, including components biotis flora and fauna. Human being and his behavior and socio-economic and socio-cultural or demographic profile including population, social activities both economic and cultural fields.

Understanding the unity of space, exactly is the unity of spatial (spatial entity), is that the presence of elements or components agihan environment are in a relationship, dependency, affect each other and follow each other in a single order thoroughly intact. Furthermore, this is referred to as ecosystems (UURI No.23 Year 1997, Article 1 number 4) is the arrangement of environmental elements that are integrated and comprehensive and mutual influence in shaping the balance of stability and productivity of the environment.

Thus, any harassment against one of the environmental component may result in changes in other environmental components. Development is essentially always lead to changes in environmental components. So that components do not experience degradation of the environment of Indonesia development-oriented Insight Development Environment (Law No. RI. 23, 1997, Article 1 Figure 3), is a conscious and planned effort that combines elements of the environment, including resources, into the development process to ensure capability , welfare, and quality of life of the present generation and future generations.

In the context of geo-physical degradation process will be dealt degradation, (geomorphology), land degradation, degradation and water quality conditions, and degradation of air quality.


II. DEGRADATION PROCESS

Within geomorphology is the degradation is the process of becoming the low surface of the earth as a result of the process of weathering, the process of moving the rocks, and the process of erosion.

The process is the disintegration of rock weathering (menjadinya rock fragments) and the decomposition of rock (menjadinya changes the chemical makeup of rocks) in place. This rock outcrop is influenced by climatic factors, topography, lithology, and vegetation or biota. Rock weathering process is the beginning of soil formation. The process of the rock movement (mass wasting, gravitative transfered, or mass movement) is a down slope movement of rock debris on a large scale from slow to fast under the direct influence of gravitational force. Motion during these rocks generally occur on steep slopes which is driven by structural geology / geomorphology of unstable rock. Based on the type of movement and type of rock, the rock motion is divided based on the type of slow to very slow movements (creep), including soil creep, creep loose stone, stone gletsyer creep, and solifluction; type of slow motion to fast (flow, flow), including lava Flow, or Earth, and debris, mudflow, avalanches; type that moves very fast (avalanche of land, land-slides), including its free fall soil material, loose rock, and rock debris, meluncurnya soil material, rock boulders, rock rubble in the field of launchers and landslides on the surface of terputar (slump) that frequently occur in the river cliffs or steep cliffs, and the last is the type terban (subsidence) that can occur as the ruins of a cave roof, plastering amblegan as a result of oil or excessive ground water.

While erosion, in geomorphology, it is too loose and terangkutnya process earth materials by the energy of water flowing geomorphology, wave-current-tsunami, gletsyer, and wind. Erosion is generally known is the erosion by water power or accelerated erosion is the erosion due to the influence of human intervention (in addition to the known geological erosion and the erosion of normal). The process of erosion occurs from the onset of rain drops hit the soil surface, is referred to the type of rain splash erosion, runoff and runoff that flows resulted in widespread erosion type sheet; surface stream that flows lead the type of concentrated flow erosion and gully erosion type.

Level the greater the danger of erosion due to deforestation and haphazard land landslides resulted in the emergence of critical lands, namely the use of farm land not in accordance with the ability to cause damage to farm land in the physical, chemical and biological orohidrologi to interfere with the functions, governance water, agricultural and socio-economic and socio-cultural, which resulted in landslides and erosion and sedimentation upstream section and flooding in downstream areas of the watershed. Makin meningkatnyqa hazards and natural disasters on developing countries, such as landslides, land, soil erosion, floods and droughts; as a result of efforts to meet the needs for food, clothing and shelter to the forgotten control and conservation of forests, soil and water; encourage the United Nations initiated natural disaster reduction efforts internationally. For those reasons, the last decade of this century 20 (1990-2000), known as the International Decade for Natural Disaster Reduction or the International Decade for Natural Disaster Reduction.


III. LAND DEGRADATION

Land degradation (excerpted from the APA Vink, Landscape Ecology and Land Use, 1983) is not integral to the conservation of land and land development is only appropriate when land degradation has occurred. When in fact the conservation of land or land development or both need to always be done while land degradation has not occurred, namely to develop the area for a special land use.

Various human activities in land use for urban, industry and agriculture has resulted in intensive land-use change at all, thereby SCOPE (Scientific Committee on Problems of the Environment) of ICSU (International Council of Scientefic Union) introduced the term transformation of the land according to a the fact that the land in the world including its waters is growing rapidly and extensively changing as a result of human activities.
Land degradation is expressed as the erosion is a phenomenon well known as a standard, at least for farmers in various countries. Manjadi land degradation now a very comprehensive subject which is seen as part of the environmental crisis in the modern world (Eckholm, 1978). Land degradation is very serious impact on the poorest countries in the world and also the inhabitants who are poor. Means, in some countries, the unavailability of food for population growth, and this is a major global problem which continues to grow.
Logging arbitrary is the main cause of land degradation. Nevertheless it is not possible the entire forest is maintained because the population needs food, as well as agricultural products and forestry such as clothing, shelter or paper. Terencanakannya uncontrolled and not properly logging is probably the greatest ecological danger. Almost impossible to give general guidance about the quantity and the way logging is still allowed in certain circumstances. This is determined by the possibilities and requirements of local or regional landscape maps based on ecological and other scientific considerations, in addition to social and economic data in the process of integration of land evaluation. The only clues are very common, is of both ecological and economic point of view which to him are considering convergence of agricultural land use that has the best fit between the land and its use in each province of a country.

In a report published by FAO for the Environment conference in Stockholm Sweden in 1972 which is the United Nations Conference, Rauschkolb (1971) mentions subjects including land degradation;

1) erosion;
2) salinization and alkalinisasi;
3) organic waste (mainly from urban areas);
4) and disease outbreaks (both for humans, animals, and growth) and the spread of organisms that spread the infection;
5) inorganic industrial waste (gas, liquid and solid)
6) pesticides;
7) radioactive materials;
8) heavy metals;
9) chemical fertilizer;
10) detergent.

IV. AIR AND WATER QUALITY DEGRADATION CONDITIONS

Some important points of water degradation, namely:
1) complete changes of water conditions in general as the main cause of floods, droughts, changes in microclimate and danger to human health;

2) The deterioration of water resources both in quantity and quality is not good because of the lack of water management and soil conservation and water pollution;

3) The destruction of water resources due to usage that exceeds the limit, causing sea water intrusion in coastal areas, compaction and amblegnya clay in the peat, all of which as a result of bad drainage;

4) Increased levels of erosion and salinization because it is not good for agricultural water management.

In the discussion of land degradation has been mentioned that the emphasis of forest ment haphazardly is a major cause of land Degras-tie. Similarly, degradation of water conditions can be caused by logging arbitrarily. Due to deforestation caused reduced evapotranspiration, infiltration, evaporation and water binding capacity; to increase the quantity of runoff that causes flooding in the rainy season and dry season drought, in addition to increasing the activity of both erosion erosion surface, groove or gully erosion, which will consequently lead to increased sedimentation and silting it up hinga river flooding.

According to Sanford (Verstappen, 1983) is the hardness of light is a state of lack of some basic commodities such as water, food plants, and grasses as a result of low rainfall or uneven distribution. Danger drought occurs mainly in semi-arid regions, as happened in Ethiopia. Areas prone to drought can be determined based on several facts, among others, rarely or absence of vegetation, the presence xerophita plants, development of wind formations like the desert and desert sand. To determine the possibility of areas affected by drought hazard information to be considered are:

1) local coarse texture and poor soil organic matter;
2) the mountainous area in the ground water;
3) region located in the arid mintakad;
4) decrease in density or changes in vegetation cover and vegetation types as a result of the pasture;
5) human activity, such as plastering water wells, which can lower the ground water.


V. AIR QUALITY DEGRADATION

Degradation of air quality can occur because of air pollution that is, an event the entry of foreign substances into the air causing air quality to decline and could disrupt or endanger the health of living beings. Causes of air pollution can come from nature are volcanic eruptions, or come as a result of human activities in industry (stationary) and moving vehicles as transportation activities. Air quality is considered based on the draft Regulation of the Minister of Health about air quality requirements of the Environment.

Air quality parameters which consist of physical parameters: temperature and humidity and wind speed and direction; chemical parameters namely: dust or pollutant particles and gases such as CO2, SO2, NOx, H2S, hydrocarbon vapors and photos oxidizing chemicals. The elements of these pollutants would be very dangerous if these elements accumulate, sector in a region with relatively long retention time. Effect caused all kinds depending on the type of pollutant or time of residence. At a certain concentration of pollutant elements can interfere with human health, animals and plants and even destroy buildings. In big cities and industrial areas of air pollution perceived opinion increasingly troubling, especially coming from a factory chimney, motorized vehicle exhaust and dust that was flying everywhere, that in time will cause a lot of serious disturbances which if not tackled early. Air and water pollution as a result of the industrial waste disposal needs careful attention, remembering the days of the upcoming industry is government policy that is taken in addition to agriculture and plantation sector. Air pollution caused by motorized vehicles is also very disturbing because in addition to the resulting effect is also relatively difficult to overcome. Similarly, noise caused ago lalangnya engined vehicles such.


VI. CONCLUSION

Air pollution, water and land have been heard going on everywhere is causing the degradation of air quality, water and land as the embodiment of the degradation of air, water and land as the embodiment of the degradation of air, water and land. Environmentally sound development of Indonesia will not break even always preserve the environment. One effort to achieve this is by requiring every plan to implement development activities Environmental Impact Assessment (EIA).


REFERENCES

Anonimous, 1997. UURI No. About 23 Year 1997 Environmental Management. Jakarta: State Ministry of Development Supervision and the Environment.

Anonimous, 1999. PPRI No. 27 Year 1999 About the Environmental Impact Assessment. Jakarta: State Ministry of Population and Environment.

Budi Harsanto, 1985. Air Pollution. EIA Course Materials Lecture PPLH UGM, Yogyakarta.
Sugeng Martopo, 1991. Degradation of Materials Lecture Course biophysical EIA PPLH UGM, Yogyakarta.

Vink, A.P.A., 1983. Landscope Ecology and Land Use. Longman Group Limited, London.

By: RATIH FITRIA PUTRI (Double Degree Master Programe MPPDAS UGM - Remote Sensing Chiba University,Japan)

FEASIBILITY STUDY ON FRESH WATER


Environment continuity is influenced by pattern, policy and the environment management order. It is certain that the policy applied and arranged must give the benefit for all stakeholders. Basically, an environment is said to have given the benefit if it can be taken a economic value from it. But there is the important elementary benefit, that is the ecological value. This value is very important because if the environmental ecology value is well-kept, the economic value of the environment will be obtained.

Natural resource is an asset which can be used toward the human life prosperity. It is also said as a potency owned by nature for supporting the continuity of life through inventarization and evaluation of natural resource, effectively and efficiently. The evaluation is aimed at controlling how much resources available (such as natural resources balance) and how they are used. Its usage should be effectively and efficiently.

The problems of water resource is the important matter to be concerned by the Local Government, in relation with the effort of improving public prosperity. Water, being one of the highly important resources, is a main thing of the human necessity. Thus, water has become a basic element for the continuity of people life. Its provision is considered one of the crucial aspects in developing regional potency to fulfill the inhabitant’s need of water or other uses. Water resource includes underground water or surface water resource.

Water resource is naturally renewable naturally, because of being an unseparable element in hidrology cycle. In reality, however, there are some restricting factors influencing its usage, in quantity or in quality. In the quantity side, water resource will experience reduction in its providing ability if the amount utilized is beyond its availability. The problems of water potency, quantitatively or qualitatively, are related with the climate condition, geomorphology, geology, kind and landuse pattern, as well as human activities. Naturally, the first three abovementioned factors are the significant factors which influence the condition and dynamic of water resource potention, either the underground water or the surface water. For that purpose, the study of water resource is need to be done that will function as a fundamental element in water resource management. Water resource becomes a highly crucial problem in Indonesia, mainly in Java island, Bali, and The Island of Nusa Tenggara.

The increasing water resource needs can not be matched by a steady cycle of water. Landuse change caused by the force of people activities has generated the change in water body formed at lands. The real example can be seen in the regions which suffer flood in the rainy season, while the same regions experience dryness in the dry season. This change has forced the inhabitants in these regions to use groundwater in replace of river water. As a result, the groundwater use increases considerably at the end of the decade. Industrialization growth which can not be balanced by the permanent water source provision by the government is the main catalyst of the ground water overuse.The impact of this excessive exploitation of water source is beginning to emerge, such as periodical declining of grond water surface, land slides, sea intrusion and many more. When the environmental impact is felt, the importance of conservation is then realized.

Water source becomes one of the control parameters conduct in land order decision. As for groundwater, land order decision must follow the groundwater cycle or the groundwater flow scheme itself. The groundwater flow scheme will be started at the recharge zone. This is the zone where water on the land surface, either rainwater or surface water, experience infiltration process by gravitational means through pores at lands/rocks or through gaps/cracks at lands/rocks. This infiltration process will accumulate in a point in which water reach an impermeable rock layer. The accumulation point will create a saturated water zone. The difference of physical condition will naturally cause water in the saturated zone to flow through gravitational force, pressure difference, rock structure control and other parameters. This condition is what is called groundwater and the groundwater flow area is then called flow zone.

In this flowing phase, groundwater frequently erupts/emerges to the surface because of being cut by topography or geology control, such as fault, the occurence of impermeable rock layer, etc. The emergence of this groundwater back to the surface is called spring, while the area in which groundwater emerges is called discharge zone. Nowadays, the criteria for discharge zone has highly extended,mainly because of human activity. The area of the groundwater emergence to the surface caused by pumping, if intensively happens, can be categorized as discharge zone.
Water resource management needs a more clear, systematic, and aimed concept. To perform the providing efforts, utilization, manufacturing, and conservation of water sources in a region, it is needed a more accurate judgement about its characteristics and utilities, availability, and quality, the exact exploration method, the calculation of potency and environmentally-friendly exploitation value.. According to various concepts and considerationsas stated above, it is important to do a study on the potency of underground and surface water, in relation with the efforts of procuring potential water resource to meet the drinking needs, in quantitative or qualitative aspects. Besides, it can be formulated a pattern and utilization level so that it can be designed its utilization and conservation zone in a specified area.

The earthquake on May 27, 2006 striking Yogyakarta and the surrounding area took over 5,700 lives and caused huge disaster to the all sides of human life. Natural disaster caused by the earthquake has brought an impact on the availability of fresh water in the villages. Many local wells have become dried. This condition contributes another difficulty for the local people to do recovery.


By: Ratih Fitria Putri (Double Degree Master Programe MPPDAS UGM - Chiba University Japan)

Relativity of Time......

Today, the relativity of time is a scientifically proven fact. This has been expressed through Einstein's relativity theory of time in the early years of the 20th century. Previously, humans not yet know that time is a relative concept, and time may change depending on circumstances. Great scientist, Albert Einstein openly proved this fact with the theory of relativity. He explained that the time is determined by the mass and velocity. In human history, no one could express this fact clearly before.

But there are exceptions; Qur'an contains information about the time that is relative! Numerous verses of this review reads:

"And they urge you to hasten the punishment. But Allah will never fail in His promise. And indeed, a day with your Lord is like a thousand years of those which you count"(QS 22:47)

"He arranges [each] matter from the heaven to the earth; then it will ascend to Him in a Day, the extent of which is a thousand years of those which you count"(QS 32:5)


"The angels and the Spirit will ascend to Him during a Day the extent of which is fifty thousand years"(QS 70:4)

In several verses mentioned that people feel time differently, and that sometimes people can feel very short of time as something old:

"[Allah] will say, "How long did you remain on earth in number of years?" (112) They will say, "We remained a day or part of a day; ask those who enumerate." (113) He will say, "You stayed not but a little - if only you had known"(QS 23:112-114). The fact that the relativity of time is mentioned very clearly in the Qur'an, which started down in the year 610 AD, is another proof that the Qur'an is the holy Qur'an.

"By time, Indeed, mankind is in loss, Except for those who have believed and done righteous deeds and advised each other to truth and advised each other to patience" (QS 103 : 1-3)


By: RATIH FITRIA PUTRI (Double Degree Master Programe MPPDAS UGM - Remote Sensing Chiba University,Japan)

Geophysic & the BIG BANG theory..... it's only the theory or "..." ?????

















Through two major projects undertaken mapping of galaxies until now, scientists have made discoveries that provide crucial support for the theory of "Big Bang". The results were presented at the winter meeting of the American Astronomical Society. The extent of the distribution of galaxies considered by astrophysicists as one of the most important legacy of the early stages of the universe that still exists today. Therefore, it is possible to refer to the information on the distribution and location of the galaxies as "a window opening onto the history of the universe."

In their research that lasted several years, two different research groups, composed of scientists England, Australia and America, managed to create three-dimensional map of about 266,000 galaxies. The scientists are comparing data on the distribution of galaxies that they collect the data from the Cosmic Background Radiation [Cosmic Background radiation] emitted into every corner of the universe, and made important discoveries regarding the origin of galaxies. The researchers who reviewed data concluded that the galaxies formed in the material that formed 350,000 years after the Big Bang, in which this material meet and gather, and then get the shape under the influence of gravity.

Two Important Information about the Standard Cosmological Model mentioned in the Qur'an, and in the Torah and the Gospel whose contents have changed after diwahyukannya, God has revealed that the universe and all matter is created from nothing; in the Qur'an , the only text that has not been corrupted, He reveals one other miraculous secret that the universe is expanding.

The formation of the universe becomes "there" from "nothingness" preached in the Qur'an as follows:

"[He is] Originator of the heavens and the earth. How could He have a son when He does not have a companion and He created all things? And He is, of all things, Knowing"(QS. Al An'aam, 6:101)

Deployment of the universe, one of the main areas of research of modern science, is revealed in this verse:

"And the heaven We constructed with strength, and indeed, We are [its] expander" (QS. Adz Dzaariyaat, 51:47)

As we have seen, two essential part of the explanation that the reference on the origins of the universe, namely the Big Bang and the expansion of the universe, preached in the Qur'an at a time when the means of astronomical observation is still very limited. This is clear proof that the Qur'an was revealed by God. The discoveries of recent science is completely consistent with what is preached in the Qur'an, and the studies once again this past draws attention to the suitability of this closely.


"Indeed, your Lord is Allah, who created the heavens and the earth in six days and then established Himself above the Throne, arranging the matter [of His creation]. There is no intercessor except after His permission. That is Allah, your Lord, so worship Him. Then will you not remember?" (Qs 10 : 3)

By: RATIH FITRIA PUTRI (Double Degree Master Programe MPPDAS UGM - Remote Sensing Chiba University,Japan)

Disaster Management Data Analysis















The Spatial Planning Document already has information which is related to vulnerable area, including prone area to landslide and tsunami, but this description is not supported by comprehensive data and analysis. The hazard information included in the Spatial Planning Document should have role to reduce disaster risk, as follows:

1. Keeping areas free of development, since Spatial Planning has the instruments at hand to keep free those areas of future development that:
(1) are prone to hazards (e.g. flood-prone areas, avalanche-prone areas),
(2) will be needed to lower the effects of a hazardous event (e.g. retention areas)
(3) will be needed to guarantee the effectiveness of response activities (e.g. escape lanes, gathering points etc.).

2. Differentiated decisions on land-use: spatial planning may also decide on land-use type according to the intensity and frequency of the existing hazard (e.g. agricultural use of a moderately hazardous flood area might be allowed whereas residential use may be forbidden).

3. Recommendations in legally binding land-use or zoning plans. Although recommendations about certain construction requirements belong to the area of building permissions, some recommendations can already be made on the level of land-use or zoning plans (e.g. minimum elevation height of buildings above floor, prohibition of basements, prohibition of oil heating, type of roof).

4. Influence on hazard intensity and frequency (hazard potential) by spatial planning: Spatial planning can also contribute to a reduction of the hazard potential, e.g. protection or extent of river flood retention areas, protective forest etc.

It was shown that hazard information has led to an enhanced understanding of future potential threats to spatial development. The multi-hazard concept is challenging but important, as it is vital for spatial planners to obtain information on all kinds of potentially adverse impacts. The organization of land use and the distribution of spatial functions can definitely support adaptation strategies and lead to a better protection of the living environment. It can support the development of appropriate adaptation strategies. The analysis of the interrelation between environmental catastrophes and regional development will enable to point out the strategies and instruments of spatial planning and land management to support the prevention hazards. Spatial risk assessment framework can help improve adaptation planning through providing relevant information to underpin the development of adaptation strategies related to land-use and spatial planning.


By: Ratih Fitria Putri (Double Degree Master Programe MPPDAS UGM - Chiba University Japan)

Tsunami Hazard Map in PARANGTRITIS - Bantul Regency - Yogyakarta Special Province
















The tsunami that hit Java on 17 July 2006 was not a small event. Initial wave height estimates were between 2 m and 3 m, but it turned out that waves were more than 7m high in some areas and traveled several hundred meters inland. The Tsunami destroyed scores of houses, restaurants and hotels. Cars, motorbikes and boats were left mangled amid fishing nets, furniture and other debris.

The research has three results, first 18 % area was destroyed in last tsunami on 2006, second close relationship of the coastal morphology and tsunami impact shown that low land area has highly destructed caused by tsunami because it was crushed on the first place. This research also proves that sand dunes have important role as natural barrier that act as water breaker. Third, 8 building clusters were classified with different building characteristics and slope condition. It is concluded from the calculation that 75 % of total area are classified into highly vulnerable, 10% are medium vulnerable and 15% low vulnerable due to tsunami disaster.


The local newspaper reported that the damage building hit by tsunami in Parangtritis coastal area generally are rattan building (wooden), used for a small shops sells food and souvenirs, non permanent. The rattan building is a flexible material, which is very strong in tension, compared to steel. It is a very cheap material.

An emergency evacuation place on the way to a hill top is effective for saving lives. The height of the place should be higher than the expected tsunami. In case of tsunami at midnight, it will be much more dangerous for the villagers to evacuate, because of the complete darkness without electricity, so indications to let them know the evacuation route should be considered. For successful evacuation, therefore higher evacuation places than the expected tsunami should be set in and/or near residential areas. There are two alternative paths disaster evacuation for this area, evacuation path to the Yogyakarta city and evacuation path to the mountain area on the east side of area which is the more SAVE ZONE from the tsunami disaster.


By: Ratih Fitria Putri (Double Degree Master Programe MPPDAS UGM - Chiba University Japan)

Tsunami...... Tsunami..... Tsunami.....











Base on tsunami historical, Tsunami disaster can make destroy and loss material of every place who get tsunami wave inundation. A Tsunami is a seismically generated gravity waves, characterised by wave periods that are in the order of minutes rather than seconds. Tsunami are sometimes referred to as tidal waves, a term that has fallen out of favor, especially in the scientific community, in recent years because tsunami actually have nothing to do with tides. The once popular term derives from their most common appearance, which is that of an extraordinarily high incoming tide. Tsunami and tides both produce waves of water that move inland, but in the case of tsunami the inland movement of water is much greater and lasts for a longer period, giving the impression of an incredibly high tide.


It is very danger for many peoples in coastal area and arround coastal zona. Tsunami disaster also can make many victims and peoples be dead. The cities who have high vulnerabilty zone of tsunami disaster, they have to make mitigation planning for prevent and recovery many loss material and peoples death. For indonesia people, tsunami disaster is very familiar in their live. From 1900 until 2006 was happen more than 19 tsunami disaster. From this case 15 tsunami disaster occured in the eastern part of indonesia which we knew in this areas also we called very active and complex seismotectonic zone. Tsunami wave in Aceh (26 December 2004) caused many people be dead. In 2006, Tsunami also occured in Pangandaran, Cilacap and Kebumen. It make conclusion that Indonesia have high susceptibility of tsunami disaster.



by: Ratih Fitria Putri (Double Degree Master Program MPPDAS GMU - Remote Sensing Chiba University Japan)

Tsunami Hazard.... Causing by Earthquake??
























What is a tsunami?
The official definition of a tsunami is: “a wave train, or series of waves, generated in a body of water by an impulsive disturbance that vertically displaces the water column”.

What causes a tsunami?
In general, anything that is capable of moving large water masses can cause a tsunami. Various sources as earthquakes, landslides, volcanic eruptions, explosions, and even the impact of cosmic bodies, such as meteorites, can generate tsunamis.

Shallow water waves
A tsunami is what we call a shallow water wave. A wave is a shallow water wave if the wavelength of the wave is much longer than the depth of the water the wave is traveling through. This is typically the case for tsunamis which have wavelengths exceeding 100 km while traveling through 5-7 km deep water. Because the rate at which a wave loses its energy is inversely related to its wave length, tsunamis not only propagate at high speeds, they can also travel great, transoceanic distances with limited energy loss (the rate at which a wave loses its energy is inversely related to its wave length).

This explains why the coast of Africa was still hit by a tsunami that originated over 5000 km away. Shallow-water waves move at a speed that is equal to the square root of the product of the acceleration of gravity (9.8 m/s/s) and the water depth - in a 6 km deep ocean a tsunami propagates with 875 km/hr, as fast as an airplane!

Difference between tsunami in the deep ocean and a tsunami approaching the coast

A tsunami behaves fundamentally different in the open ocean and close to the coast in shallow waters (Figure 2). A tsunami in the deep ocean has very long wavelengths and very low amplitude. Approaching the shore the tsunami will slow down in speed and amplitudes will increase dramatically. This is due to the fact that the tsunami’s energy . ux, which is dependent on both its wave speed and wave height, remains nearly constant. Consequently, as the tsunami’s speed diminishes as it travels into shallower water, its height grows. Because of this shoaling effect, a tsunami, imperceptible at sea, may grow to 10-50 meters near the coast.

The probability of tsunami hazard is assumed same as earthquake because it will happen when earthquake occur. But probability for landslide is higher than others because not only earthquake and tsunami that is causing landslide but also precipitation too (hard rain). In this case, we assumed that high rainfall also happen when rainy season. As we know, Indonesia has two seasons in one year those are dry season and rainy season. It means the probability of landslide hazard is 1 time per year (in rainy season) so the value is 1 (one).

Tsunami effects:
There are several speci. c characteristics related to tsunamis that make it clearly distinguishable from other types of waves and that are the cause for the devastating force a tsunami might have:
* Tsunamis can appear as a falling or rising tide, waves or bore
* Tsunamis can last for several hours.
* A tsunami consists of several wave trains following each other.
* A pattern of high water levels is alternated with low water levels



Created by: ratih_nabila as Individual Assignment Double Degree Environmental Remote Sensing GMU-CU, 2009.