Spatial Planning Around Mount Slamet Based on Geophysic Studies as Preventive Way Towards Volcanic Disaster

Reza Prima Yanti, Agus Santosa, Indriati Retno Palupi, Wahyu HidayatUniversitas Pembangunan Nasional “Veteran” Yogyakarta

Jl. SWK 104 (Lingkar Utara) Condong Catur, Yogyakarta, Indonesia. Postalcode 55283Email: reza.pyanti@yahoo.com

ABSTRACT

Volcanic eruption is one of the frequent disasters in Indonesia. One of the volcanoes that holds the potential for disaster is Mount Slamet located in Province of Central Java. Mount Slamet still quite active and has the potential to erupt again, causing the area around it has a fairly high level of vulnerability to disaster in the future. The affected areas of eruption is five administrative regions that intersect directly with Mount Slamet, namely Purbalingga, Banyumas, Tegal, Brebes and Pemalang. Based on geophysic studies, identified that Purbalingga and Banyumas are two areas that potentially affected in case of eruption. From these findings, then this article will explain how to think significantly to reduce the number of casualities, damage, and disruption from future disasters, as well as create safe, resilient and adaptive communities, regions and nations. From the research that has been done by using descriptive method, the arrangement of space around the area of Mount Slamet and relocation of residents from risk zone to safe zone as disaster mitigation is a strategy that can be done by considering aspects of preparedness and availability of relocation’s area. Beside that, aspect of socio-cultural need to do in relocation by approaching the citizens through socialization and give understanding. Through spatial planning that considers aspects of volcanic disasters, the development in the region around Mount Slamet can be more effective both in terms of infrastructure and in terms of population for the sake of a sustainable development.

Keywords: Volcanic, Preventive to Disaster, Mount Slamet, Spatial Planning

Background of the study

Gunung Slamet with an altitude of 3432 meters is one of the volcanoes type A that had erupted since 1600. The mountain is located in the Province of Central Java, precisely in 7º14'30" South Latitude and 109º12'30" East Longitude, with administration area belong into five districts namely Brebes, Tegal, Pemalang, Banyumas and Purbalingga (Maryanto et al, 2012). On April 30, 2014 the status of Gunung Slamet increase of alert (level II) to alert (level III). The status by the Centre for Volcanology and Geological Hazard Mitigation (PVMBG) is given as a warning to communities living around volcanoes. The alert status means that all of the data showed that the volcanic activity which occur can be continued to an eruption or lead to circumstances that can lead to disaster (BNPB, 2014).

Implementation of disaster mitigation in Central Java still have some problems that disaster management is still focused on emergency response activities, still rest on the role and capacity of local government, lack of effective coordination among the institutions of the Central Government and District, and coordination among other stakeholders such as private enterprises, NGOs, universities, community organizations, the media and the public. Thus covering various aspects of disaster management both before (pre-disaster), at the time of the disaster and the aftermath of the disaster itself that are sustainable and involve various sectors and at various levels vary from village level to the international (Renstra Sekrektariat BPBD Jawa Tengah, 2008-2013).

Literature Review

The disaster is an event or series of events that threaten and disrupt the lives and livelihood caused by natural factors and non-natural factors and human factors, resulting in the emergence of human lives, environmental damage, loss of property, and psychological impact (Law No.24 of 2007). Also John

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Oliver in the Handbook of Disaster Research (2007: 9) defines disaster as part of the environmental process that greater than the expected frequency and magnitude, causes major 'human hardship with significant damage' (part of the larger environment of frequencies expected and the main cause of human difficulties with significant damage). Meanwhile, the United Nations define disaster as a serious disruption of the functioning of society, causing widespread human, material or environmental losses, which exceed the ability of the affected society to cope using only its own resources (malfunctioning of a serious public causing harm to human, material loss or environmental damage that exceeds the ability of the affected community in which way to address such damage just by using the resource itself (UN, 1992).

Meanwhile, according to the National Disaster Management Agency (BNPB, 2008) disaster is an event or series of events that threaten and disrupt the lives and livelihood caused by both natural factors and/or factors of non-natural or human factors that lead to the emergence of human lives, damage to the environment, loss of property, and psychological impact. Disaster itself can be classified into two categories, natural or environmental disasters and disasters due to human activities or the creation (technology) (Gustin, 2005: 61). Includes natural disasters such as cyclones, tornadoes, floods, and earthquakes. While other examples of disasters caused by human activity or incidents include accidents tech materials, radiological accidents, transportation accidents, bombings and electrical failure. According to the Ministry of Social Affairs, disaster management is a dynamic process, continuous and integrated to improve the quality of the measures related to the observation and analysis of disasters and disaster prevention, mitigation, preparedness, early warning, emergency response, disaster rehabilitation and reconstruction. While according to the Disaster Management Act 24 of 2007 states that implementation of disaster management is a series of efforts that include the establishment of development policies that are at risk of the onset of the disaster, disaster prevention, relief and rehabilitation.

Disaster management activities can be divided into three main activities (Coppola, 2007):1. The pre-disaster activities that include prevention, mitigation, preparedness and early warning.2. Activities during disaster which includes emergency response activities to alleviate suffering while,

such as the activity search and rescue (SAR), emergency assistance and evacuation.3. Activities include a post-disaster recovery activities, rehabilitation and reconstruction.

Pre-disaster phase activities have been widely overlooked, but quite the pre-disaster activities at this stage is very important because what is already prepared at this stage is a capital in the face of disaster and post-disaster. Very few government and private together with the community to think about the steps or activities of what needs to be done in the face of disaster or how to minimize the impact of disasters (Schneid and Collins, 2001). The activities undertaken when a disaster occurs immediately upon occurrence of a disaster, to cope with the impact, especially in the form of rescue and property, evacuation and displacement, will get full attention from both government and the private shared society. At the time of the disaster, usually so many people are paying attention and lend a hand provide energy assistance, moral and material. The amount of assistance is an advantage that should be managed properly, so that any aid received can be appropriate, effective, precise benefit, and occurs efficiency (Higgins in Linda and Donald, 2005: 65). The activities in post-disaster phase is a process of improvement of the condition of the affected people, by re-creating infrastructure and facilities in its original state. At this point to note is that the rehabilitation and reconstruction will be implemented must fulfill the standards of disaster, not only do physical rehabilitation but also should be noted the rehabilitation of the psyche that occurs as fear, trauma or depression (Schwab, 1998).

Methodology

Gunung Slamet still belong to the active volcanoes and has the potential to erupt. As a result, the area located around it threatened by the impact of the eruption. The regions are Banyumas, Purbalingga, Brebes, Tegal and Pemalang. The magnitude of the losses incurred in case of eruption, local governments and communities in the area around Gunung Slamet need to adapt and change the paradigm to face the threat of volcanic disasters. Volcanic disasters can not be predicted for the time

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of eruption. This entails not only emphasizes the aspects of post-disaster, but it is more important aspects of the pre-disaster. That’s why the efforts made should be prepared before a disaster happen again because it would cause a lot of loss of life and material. This study provide recommendations for the policy makers in the field of disaster mitigation as one step in minimizing and anticipate the magnitude of losses in case of eruption of Mount Slamet. The recommendation made based on the mapping of zones prone to eruptions of Mount Slamet then analysis towards the susceptibility and capacity of community in disaster zone around Gunung Slamet.

Results and Discussion

Gunung Slamet is one of the volcanoes in Central Java, which is still active but the pattern of eruptions is unknown and different with the case of Gunung Merapi. Gunung Slamet located on five border districts, Purbalingga, Banyumas, Pemalang, Tegal and Purwokerto. It is also adjacent to two major faults that exist in Central Java that meeting to be around Lukulo. Based on information obtained from PVMBG, areas prone to the eruption of Gunung Slamet dominated in the east of Mount Slamet.

Figure 1. Map of Prone to the Eruption of Gunung Slamet (PVMBG)

Based on information obtained from Figure 1, the researchers wanted to find a picture of the subsurface of Gunung Slamet which leads into the dominance of disaster-prone areas in case of eruption of Gunung Slamet. The lack of seismic data for Gunung Slamet be an obstacle in this study, but based on information obtained from PVMBG there is an earthquake vulkanotektonik which also affects the activity of Gunung Slamet, the researchers used the help of tectonic earthquakes with moment magnitude scale ≥2 to determine the image below Mount Slamet surface.

Modeling for tomography technique is used in picture below the surface of Mount Slamet with initial velocity model AK 135. Meanwhile, to help process data processing used Matlab software, Petrel and Lotos. Before the tomography, the data must be relocated from earthquake catalog in advance to

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obtain subsurface picture better. The relocation process is conducted by using relocation Guided Grid Search.

The results of the subsurface picture in the vicinity of Mount Slamet shown in Figure 2 below:

(a)

(b)

Figure 2. (a) Hiposentrum (epicenter) before being relocated and (b) Hiposentrum

Based on the second image obtained information that the hypocenter after relocating more convergent and can be split between low-speed zones (weak zone) and high-speed zones. Low speed zones are marked by the color orange to red, while the high-speed zone marked in blue to dark blue. Low speed zones are usually associated with hot fluid that can be interpreted as magma. Through the subsurface picture can be seen that the low speed zone area more to the east of Mount Slamet, meaning that the process of magma discharge is estimated more to the east of Mount Slamet.

When viewed from the surface, taking into account the existence of rivers and topography of the area around Mount Slamet, then Banyumas and Purbalingga be the areas most prone to the eruption of

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Mount Slamet. From Figure 1 it is known that many rivers flow from Mount Slamet numerous in two areas. The flow of the river can bring material cold lava of Mount Slamet. While from Figure 2 that a large enough potential weak zone in the area around Mount Slamet. Of the two pictures look a match between the spread of lava flows on the surface with the spread of a weak zone that is identical with the magma below the surface.

Based on the study of volcanic disasters, it is known that six districts in Banyumas highly vulnerable to disaster if the eruption of Mount Slamet. These areas are as follows:

1. District Sumbang, disaster-prone areas include Limpawukus Village, Village Kotayasa, Gandatapa Village, Village Sikapat, Banjarsari Kulon village, Village Banteran, Susukan, Ciberem Village and Village Banjarsari Wetan.

2. District of Baturaden, disaster-prone areas include Karangmadu Village, Village Ketenger, Karangtengah Village, Village Karangsalam, Kemutug Lor village, Rempoah Village, Village Kemutug Kidul and Kebumen.

3. District of Kedungbanteng, disaster-prone areas include Melung Village, Village Windjaya, Baseh Village, Village Kutaliman, Kalikesur Village, and Village Kalisalak.

4. District of Cilongok, disaster-prone areas include Sokawera Village, Village Gununglurah, Sambirata Village, and Village Karangtengah.

5. District of Pekuncen, disaster-prone areas include Pekuncen Village, Village Glempang, Tumiyang Village, Village and Village Pasiraman Krajan.

6. District of Karanglewas, disaster-prone areas includes the Village Sunyalangu and Babakan Village.

Besides Banyumas, Purbalingga also includes disaster-prone areas of Gunung Slamet. There are ten villages were located fairly close to the peak of Gunung Slamet. The villages are scattered in four districts are: District Karangreja (three villages), District Mrebet (three villages), District Kutasari (three villages) and the District Bojongsari (one village). From ten of the villages, there are two hamlets that were located very close to the peak of Mount Slamet namely Hamlet Kutabawa in Bambangan village and hamlet Gunungmalang in Serang village. Distance two villages just 9 km from the summit of Gunung Slamet. While other villages within approximately 10-14 km to the peak of Gunung Slamet.

The level of capacity and vulnerability of community in Kabupaten Banyumas and Purbalingga which live in prone zone of Gunung Slamet can measured from the aspect of demographic, economic, social and public accessibility level in each district:

1. PopulationAnalysis of the population, judging by the quantity, quality and the embodiment of space as a manifestation of the characteristics of the quality and quantity of the population. The population problem is primarily the number of population by sex, age group and population density. Residents in Banyumas, spread in 27 districts (331 villages), 9967 RT and 1,994 RW amount to 1.605.579 inhabitants consisting of 802.316 men and 803.263 women, with sex ratio 99,88 which means that the number of males 0.12% less than the number of females. With an area of approximately 1.328 km2 Banyumas district inhabited by 1.605.579 people, the average population density is 1.209 people per km2 (BPS Banyumas).

Residents in Purbalingga, spread in 18 districts (224 villages and 15 urban villages), 5069 RT and 1,546 RW amounted to 894.062 people, made up 441.706 men and 452.356 women, with sex ratio of 97,65. The number of households reached 222.676, or an average member of each household is four

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people. By age group, the population Purbalingga it consists of 0-14 years 26.25% and 15 years and above amount to 73.75%, thus the rate of population growth Purbalingga was 1.06% and the population density is 1,150 people per km2 (BPS The Purbalingga).

2. EducationThis aspect can measured by see the educational level that can be completed by a number of residents in each district. Aspect of education is considered important because it is one factor that can influence people's understanding of disaster vulnerability, so that it will determine the level of capacity and vulnerability. Aspect of education is primarily the level of education that can be solved by a number of residents in disaster-prone areas. Most people living in disaster-prone areas of Banyumas and Purbalingga can only complete their education into the elementary school level. A small part can complete they education at the secondary level, either the first level or the upper level and the rest may be graduated at college or university. Under the conditions of education levels, most people in Banyumas and Purbalingga, the level of public understanding of the existing environmental conditions is still low. By contrast, if the majority of these people are highly educated, then the level of understanding will be high because generally people who have high education level of social relations more widely and easily receive information, in particular regarding the level of vulnerability to disasters in the region.

3. LivelihoodAspects of livelihood is based on the type of livelihood for the majority of local people in order to be able to support his family. The problems of livelihood becomes very important in a land use because it is basically done to create a comfortable environment for residents on an ongoing basis, so it will affect the level of capacity and vulnerability. The problem of livelihood is primarily livelihoods undertaken by a number of people to be able to support his family. Residents in Banyumas most of his work was as farmers and more dominated by men. It is similarly with the population in Purbalingga. Many residents work as farmers and will intensify cultivate paddy fields and gardens there is even very possible that they are doing agricultural extension to a land that was supposed to be a protected area, so it is feared will be closer to the source of the disaster. This will result in the level of vulnerability of the community to be higher.

4. Income LevelThe level of income can affect the level of capacity and vulnerability. The income level of the people in disaster-prone areas affected by the type of livelihood is the source of their livelihood. Livelihoods of local people in Banyumas and Purbalingga mostly farmers with little income. In order to find additional revenue to provide for the family in addition they work as labour of construction in the city. As women are more at home taking care of children and doing household chores everyday.

5. Social CommunitySocial condition in Banyumas and Purbalingga still running well marked with close relations (guyub) villagers in implementing mutual assistance for the purposes of the village. Mutual cooperation is a form of cooperation among villagers to do certain jobs that are considered useful for the common good. It is very possible for interacting between people and cultures of mutual cooperation is still valid will be able to help the community and reducing the burden of disaster victims. Civil society is one of the factors that may affect the level of community vulnerability and capacity in disaster-prone areas. The high level of social community in the form of gotong royong activities are still carried out will affect the level of vulnerability of the community to be low.

6. Understanding Society Toward Environmental Conditions

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The level of capacity and vulnerability also heavily influenced by the level of public understanding of local conditions. The level of public awareness of environmental conditions will influence the decision to perform actions aquaculture activities around Gunung Slamet. People's understanding of the environmental conditions that is prone to volcanic disasters that high would make the people to be careful in utilizing the available land, so it will be able to reduce the level of vulnerability. Communities know that their village is prone to volcanic disasters of socialization conducted by the district, sub-district and village, while others found out after the eruption happened. In response, most of them are concerned, especially people who are in highly vulnerable areas, but they still carry out daily work in their own fields by improving and understanding of natural phenomena that exist.

7. Accessibility CommunityThe level of accessibility that is owned by the people in disaster-prone areas will also affect the level of capacity and vulnerability to the condition of eruption disaster-prone areas. The level of public accessibility seen from the convenience of the public in their daily activities and achieve one location to another. Ease of society in the long reach of a region is an effort to reduce the level of vulnerability that exists in society. Infrastructure such as roads and bridges are used to facilitate the activities or linking one location to another is one of the variables used to determine the level of public accessibility. Infrastructure of roads and bridges in disaster-prone areas Banyumas and Purbalingga not in good condition and worth, even still in very poor conditions. Infrastructure such conditions will reduce the mobility and activity of the local community and very likely will hinder the process of disaster mitigation especially during an eruption that could increase the vulnerability of the community.

According to the analysis of seven aspects above, we can see that the level of education, socio-economic and public accessibility capacity is still low. This causes the vulnerability Banyumas and Purbalingga people living in disaster-prone areas to be high for the affected eruption of Gunung Slamet. A high vulnerability should be a factor that encourages people to stay away from disaster-prone areas, but people in areas prone to disasters did not know their relationship to and stay and perform daily activities in disaster-prone areas of Gunung Slamet. Land use by communities in disaster-prone areas both for settlement, cultivation fields, plantations and farms greatly influenced by social and economic conditions of society in meeting basic needs.

Low incomes make settlements and land occupied as the only property owned in order to meet the economic needs of each community in disaster prone areas. Besides that, a fraction of the people who use the land in disaster-prone areas is caused by availability of water and air is relatively clean. In addition to that reason, most people in disaster-prone areas think the price is a more habitable land in the area below Mount Slamet is high enough so that the revenues and capabilities they feel do not have the ability to buy land more habitable. If this condition continues, the tendency of victims and losses at the time of the eruption of Gunung Slamet will be even greater. Therefore, the local government should organize the space and land in the area of Mount Slamet as a step in reducing risk and avoiding disasters that may occur in the future.

The spatial room in the area of Gunung Slamet should serve as a protected forest that is used to preserve the environment. But the land is used as a public land for settlement and perform daily activities, causing irregularities in land use in the area of Gunung Slamet. Besides the enactment of Law No. 26 Year 2007 regarding the arrangement of space, Banyumas and Purbalingga government still needs to do an evaluation of spatial planning and land use in disaster prone areas by considering factors catastrophic eruption of Mount Slamet. There are some recommendations that need to be done

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by the government Banyumas and Purbalingga for spatial planning in order to avoid the risk of catastrophe posed by the eruption of Mount Slamet, as follows:

1. Recommendations for long term:a.) The Government of Banyumas and Purbalingga need to resettlement community living in

protected forest areas or disaster-prone areas and limit land use with activities that support the function of protected forest.

b.) Approach to the people who use the land in the area of protected forest functions to be willing for the relocation and site preparation for the relocation that more safe and good for economic activities.

2. Recommendations for short term:a.) The government increased the capacity of the community in the form of community

empowerment through training and non-formal education. Thus, the public's understanding of the environmental conditions can be increased and the level of their vulnerability to disasters can be reduced.

b.) The government provides the means to track roads and evacuation of people living in disaster-prone areas, especially villages in Banyumas and Purbalingga were located very close to the peak of Mount Slamet thus at high risk of disaster.

Conclusion

Based on the natural characteristics of Banyumas and Purbalingga which is located mainly in the mountains until the foot of the mountains can influence the level of capacity and vulnerability of local communities. Community vulnerability and capacity in land use is a kind of livelihood sectors are mostly farmers with relatively low income levels. In addition, community vulnerability and capacity is also affected by population sector, educational level, social level and the level of understanding of the environmental conditions that cause land use of Gunung Slamet. Based on the policy of spatial planning and land use of existing conditions, there are some deviation from the existing spatial planning policies and the government's policy on spatial planning and space utilization. Land use in Banyumas and Purbalingga occur at varied locations, ranging from land sloping land with slopes of low to high. Deviations land use occurs in the use and function of protected forest area supporting functions should not be used for livelihood population and settlements. Thus, this study recommends to undertake control of land use in disaster prone areas of Gunung Slamet. However, for design of spatial planning need experts in the field of spatial and urban areas (urban design) to create a zone free of influence or impact of the disaster. Thus, it will be realized that the adaptive community development and have wrought stay viable.

References

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