Vulnerability and tsunami disaster on the west coast Banten province, Indonesia

ABSTRACT

Indonesia is located at the confluence of the world’s tectonic plates, causing frequent tsunami disasters. An area in Indonesia prone to a tsunami is the Sunda Strait, which has an active underwater volcano, Mount Krakatau. One of the tsunami disaster mitigation measures is to make a map of the level of vulnerability of coastal areas to tsunami disasters. Spatial analysis of the vulnerability of coastal areas to the tsunami disaster employs the overlay method of coastal area vulnerability parameters using Geographic Information System software. The parameters used in analyzing the level of tsunami vulnerability are (1) land elevation, (2) land slope, (3) land use, (4) distance from the coast, and (5) distance from the river. The level of vulnerability is divided into five categories: very high, high, medium, low, and very low. Of all the research areas, those included in the very high vulnerability category (33.56 ha) areas included in the high vulnerability category are 3923.62 ha.

KEYWORDS:

• Coastal
• overlay
• spatial analysis
• geographic information system
• vulnerability category

1. Introduction

Indonesia is known to have the second-longest coastline in the world (Baietti et al., 2013). Indonesia is at the confluence of the world’s tectonic plates. This condition resulted in Indonesia being on an active earthquake and volcanic path (Nontji, 1993). Tectonic and volcanic earthquakes can potentially cause very dangerous tsunamis on the coast. Furthermore, Indonesia is prone to disasters, such as earthquakes, tsunamis, flash floods, and landslides (Muzani et al., 2022). Tsunamis are large waves generated by earthquakes or volcanic eruptions that cause great damage (Hutabarat & Evan, 2008). According to Malik et al. (2009), tsunami waves can be caused by several factors, such as earthquakes, underwater volcanic eruptions, large avalanches on the seabed, and the impact of celestial bodies (meteors). Meanwhile, Diposaptono and Budiman (2006) stated that empirically, if an earthquake has a magnitude of 6.5 on the Richter Scale (SR) and the epicentre is less than 60 km from the seabed, a tsunami will occur.

The potential for a tsunami exists in the Mediterranean region. The risk varies between regions (Papadopoulos & Fokaefs, 2005). Natural disasters are events that can cause damage and have a major impact on human life and activities (Alcantara-Ayala, 2002; Slaymaker, 1997). The ability to recover from the impact of a disaster is highly dependent on capacity (Guzzetti et al., 1999).

Therefore, disaster management is important to minimise loss of life. Maps can show the spatial patterns of natural phenomena as well as the impacts and dangers of natural disasters (Bathrellos et al., 2008; Fava et al., 2016; Holleran et al., 2015; Jafari & Bakhshandehmehr, 2016; Miller et al., 2015; Papadopoulou-Vrynioti et al., 2013; Soulard et al., 2016; Xu et al., 2015; Yuan et al., 2016). Maps can provide information on the spatial distribution of hazards such as landslides, floods, and earthquakes and are an important tool for environmental planners and managers (e.g. Bathrellos et al., 2009; Chousianitis et al., 2016; Das et al., 2013; Guzzetti et al., 1999; Hopkins, 1977; Rozos et al., 2013; Skilodimou et al., 2003; Youssef et al., 2015). Geographic Information Systems (GIS) can be used in estimating various natural hazard phenomena and land use (Burger, 2008; Chen et al., 2003; Collins et al., 2001; Papadopoulou-Vrynioti et al., 2014; Svoray et al., 2005).

The tsunami disaster is destructive and causing a lot of losses. The 26 December 2004, tsunami in Aceh caused a loss of around 180,000 lives (Tarigan, 2005). The eruption of Mount Krakatau on 27 August 1883, caused a tsunami with around 36,000 fatalities (Tarigan, 2005), and it was recorded in the western coastal areas of Banten Province and southern Lampung Province that the tsunami wave heights reached 30 metres. A tsunami of this height would immediately destroy the entire area in its path. Therefore, actions are needed to reduce or minimise the potential risk of the disaster (mitigation) (Jokowinarno, 2011).

One of the most basic tsunami disaster mitigation efforts is creating a tsunami vulnerability map. Using geographic information system software, Tsunami vulnerability maps are made by managing spatial data. The main characteristic of geographic information systems is their ability to analyse systems such as proximity and overlay analysis, which is called spatial analysis (Handayani et al., 2005). The use of geographic information system software has been widely applied in spatial or spatial research. For example, research by Islam et al. (2014) determined tsunami risk and vulnerability in Kebumen; Faiqoh et al. (2013) made a map of coastal vulnerability to tsunami disasters in the Pangandaran Beach area, West Java; Mardiyanto et al. (2013) studied tsunami vulnerability with a geographic information system in Bantul Regency; Firmansyah (2012) made a vulnerability index of Pangandaran Beach due to the tsunami disaster; Oktariadi (2009) determined the tsunami hazard rating (a case study in the Sukabumi Coastal area); Sengaji (2009) made a map of the level of tsunami risk in Sikka City, East Nusa Tenggara; Setiawan (2006) made a map of tsunami sensitive areas in the coastal areas of East Nusa Tenggara Province; and many others.

Indonesia is located in a seismic active region where tsunamis often occur. One tsunami-prone area in Indonesia is the west coast of Java, such as the coastal areas of Serang, Banten. In this study, a spatial analysis of the vulnerability of the west coast region of Banten Province to the tsunami disaster uses a geographic information system. There are 14 earthquake-prone points with indications of a tsunami, namely in Serang, Pandeglang, and Cilegon City, caused by the fault of the Sunda Strait plate and the threat of Mount Krakatau. In addition, this location has a fairly high population density and economic activity; the Suralaya PLTU is the largest electricity supplier in Indonesia and a link between the islands of Sumatra and Java. Therefore, it is important to map the vulnerability of this location as a mitigation effort. The parameters used to determine the level of environmental vulnerability to a tsunami are land elevation, slope, land use, distance from the coastline, and distance from the river. These parameters are processed using geographic information system software to produce a tsunami vulnerability map. The results of the vulnerability map are then be interpreted to determine which areas are vulnerable to a tsunami disaster. This research aims to determine and map the level of tsunami vulnerability in the west coast area of Cilegon City and parts of Serang Regency, Banten Province, using Geographic Information System software.

2. Methodology

This research was conducted with the integration of remote sensing data and GIS. Preparation of thematic maps was carried out by using ArcGIS 10 software. The tsunami vulnerability level map was analysed by combining all parameters of coast vulnerability on tsunamis such as elevation (topography), slope, distance from the shoreline (coastal border), distance from the river (river banks), and land use.

A field survey was conducted in 3 areas (Cilegon City and parts of Serang Regency) (Figure 1) to obtain data on the condition of the study area and spatial data from the local government. The observation conducted during the field survey was to visually investigate the appearance of beaches and coastal features, like the shape of the coastline, vegetation coverage, and land use.

Figure 1. The location of the research study.

The research location is focused on the west coast of Banten Province. According to Law Number 23 of 2000, the geographical boundary of Banten Province is in the north, bordering the Java Sea; the eastern boundary of the Special Capital Region of Jakarta and West Java; the southern boundary is the Indian Ocean; and its western boundary is the Sunda Strait.

2.1. Data and tools

Data used in this study are secondary data and field survey data. Field surveys were conducted using GPS equipment. Image, elevation, and bathymetric data were obtained from the official website of the data provider (Table 1). Population and spatial data of the Pangandaran area were obtained from the relevant government agencies of the Ciamis regency.

Table 1. Data needed in a tsunami vulnerability analysis.

No.	Parameter	Data	Data source	Resolution
1	Land elevation	GDEM ASTER	Earth Explorer, USGS (https://earthexplorer.usgs.gov)	30 m
2	Land slope	GDEM ASTER	EarthExplorer, USGS (https://earthexplorer.usgs.gov)	30 m
3	Land use	RBI Map	Geospatial Information Agency	Scale 1:25000
4	Distance from the coastline	RBI Map	Geospatial Information Agency (http://tanahair.indonesia.go.id)	-
5	Distance from the river	Hydrographic Data	Geospatial Information Agency (http://tanahair.indonesia.go.id)	-

2.2. Data analysis

Analysis of tsunami vulnerability level was determined using merging and overlay methods. Parameters used to determine tsunami vulnerability were slope, elevation, land use, distance from shoreline (coastal border), and distance from the river (river banks). Based on those 5 parameters, a matrix to define tsunami vulnerability level was prepared, as shown in Table 2

Table 2. Matrix of coastal vulnerability parameters against the tsunami disaster.

No	Parameters	Weigh (%)	Very High	Score	High	Score	Moderate	Score	Low	Score	very low vulnerability	Score
1	Elevation (m)	25	<10	5	>10–25	4	>25–50	3	>50–100	2	>100–350	1
2	Slope (%)	20	0–2	5	2–5	4	5–15	3	15–40	2	>40	1
3	Land use	15	Settlement, field, forest, swamp	5	Garden/terrestrial vegetation	4	Field/more	3	Shrubs, Grass, bare soil	2	Forests, Rocks and limestone rock	1
4	Distance from the shoreline (m)	20	500	5	>500-	4	>1000-	3	>1500-	2	>3000	1
5	Distance from the river (m)	20	100	5	1000 >100–200	4	1500 >200–300	3	3000 >300–500	2	>500	1

(Source: Faiqoh et al., 2013; Firmansyah, 2012; Sengaji, 2009; Setiawan, 2006).

Data processing begins with collecting the required parameter data (Table 1) to obtain a tsunami vulnerability map. Each of these parameters will have a different effect. Therefore, it is necessary to determine the weight and score of each parameter according to the magnitude of their influence. These parameters will have a different effect; so, it is necessary to determine the weight and score of each parameter according to the magnitude of their influence. Parameters that are considered to have the greatest influence on tsunami vulnerability will have the greatest weight. The greater the influence of these parameters on tsunami vulnerability, the greater the weight value, and vice versa (Sengaji, 2009). The determination of weights and scores in this study refers to Faiqoh et al. (2013), Firmansyah (2012), Sengaji (2009), and Setiawan (2006).

The data collected is processed to obtain spatial data. The data processing scheme can be seen in Figure 2.

Figure 2. Research flow chart.

2.3. Parameter of regional vulnerability to tsunami disaster

The parameters used to determine the level of environmental vulnerability to tsunamis are land elevation, slope, land use, distance from the coastline, and distance from rivers. The environmental parameters are classified based on a matrix (Table 2), so that they can be spatialised.

2.4. Land elevation

Land elevation (topography) is one of the important parameters that influence an area’s vulnerability to a tsunami disaster. Coastal areas with low elevations will be vulnerable to tsunamis and vice versa. Areas that are potentially vulnerable to a tsunami are assumed to be coastal areas with an elevation of less than 25 m. This figure is determined by the Rehabilitation and Reconstruction Agency (BRR), which states that the maximum tsunami wave height reaching the coast ranges from 4 to 24 m (Soleman et al., 2012).

2.5. Land slope

The slope of the land is a measure of the slope relative to the horizontal plane, which is generally expressed in percent (%) or degrees (º). In this study, the slope units are in percent (%). The slope of the land is affected by the height of the tsunami waves (run-up). The steeper the land, the lower the tsunami wave height (Sengaji, 2009). The land slope affects coastal areas’ vulnerability to tsunami disasters. When a tsunami hits a steep coast, it does not go very far inland. This is because the tsunami is stuck and will be reflected back by the coastal cliffs. Meanwhile, on a sloping coast, a tsunami can hit freely for several kilometres inland (Subarjo & Ario, 2015).

2.6. Land use

Land use is a parameter that influences the level of vulnerability of a region to a tsunami disaster. According to Marfai (2011), most coastal areas are characterised by dynamic and complex (multi-function) land use. This complex land use is one of the reasons why coastal areas are prone to disasters.

2.7. Distance from the shoreline

Land use in coastal areas must pay attention to the distance from the coastline to reduce an area’s vulnerability to a tsunami disaster. According to Santius, the height of the tsunami waves will decrease as the distance increases when the waves are on the shoreline. Referring to the Law of the Republic of Indonesia Number 27 of 2007 on the management of coastal areas and small islands, the coastal border is a land along the edge whose width is proportional to the shape and physical condition of the beach, at least 100 metres from the highest tide point to land (BNPB 2007). In this study, the distance from the coastline is classified into five categories: 500 m, >500-1000 m, >1500–3000 m, and >3000 m; this classification refers to Faiqoh et al. (2013).

2.8. Distance from the river

The distance from the river affects the susceptibility of an area to tsunamis. This is because a tsunami entering a river canal will cause greater damage due to a concentration of tsunami energy pushing the tsunami further inland (Sengaji, 2009). Therefore, it is necessary to pay attention to land use from a distance.

From the river to reduce the area’s vulnerability to the tsunami disaster. The distance data from the river is obtained from the hydrographic data of the Geospatial Information Agency (BIG). Referring to Firmansyah (2012), the distance from the river was carried out at a distance of 100 m; >100–200 m; >200–300 m; >300–500 m; and >500 m.

2.9. Tsunami vulnerability level analysis

The parameters used (Table 2) are grouped into five vulnerability categories: very high, high, moderate, low, and very low (Faiqoh et al., 2013). The category is quantified as a vulnerability score from 1 to 5. In determining the level of vulnerability, a calculation is also carried out by giving weight to each parameter. Ultimately, the total score is multiplied by the weight that will be included in the vulnerability category. The value of each class is based on the calculation of the following formula (Muzaki, 2008):

(1) $\mathbf{N}=\sum \mathbf{Bii}\mathbf{x}\mathbf{Si}$(1)

where:

N = total weight of the value

Bi = the weight assigned to each criterion

Si = the score for each criterion.

i = i^th Parameter

The interval for each class is obtained by multiplying the maximum value of each weight and score minus the number of times the minimum value, which is then divided by the number of parameters used. Mathematically, the class intervals for the level of tsunami vulnerability are formulated as follows (Muzaki, 2008):

(2) $\sum (\mathrm{Bi}\mathrm{x}\mathrm{Si})\max -(\mathrm{Bi}\mathrm{x}\mathrm{Si})\min$(2)

n

where: L = the width of the class interval.

n = the number of class parameters.

The result of this calculation will be the class interval value used to determine the classification category of the area’s vulnerability to the tsunami disaster. The calculation using the formula (2) shows that a class interval width of 0.95 is obtained with a minimum N value of 0.25 and a maximum N of 5. The value of the very low category vulnerability level is obtained from the minimum N value of 0.25 plus the class interval width, i.e. 0.95. The low susceptibility value is obtained from the maximum class interval of 1.2 plus 0.95; likewise, for moderate, high, and very high vulnerability values. The class intervals for each vulnerability level category are shown in Table 3.

Table 3. Tsunami vulnerability class interval.

No.	Vulnerability level	Class Interval
1	Very low	0.25–1.2
2	Low	1.21–2.16
3	Moderate	2.17–3.12
4	High	3.13–4.08
5	Very High	4.09–5.04

3. Results and discussion

3.1. Land elevation

The results of the land elevation mapping in this study are shown in Figure 3. The mapping of the level of vulnerability of the land elevation in this study was divided into five categories of vulnerability: very high (0–10 m), high (>10–25 m), medium (>25–50 m), low (>50–100 m), and very low (>100–350 m). Figure 3 shows that areas with elevations between 0 and 10 metres above sea level are included in the very high vulnerability category as in Ciwandan District (Gunsugih Village) and Anyer District (Anyar Village). Areas with altitudes > 10–25 metres above sea level are included in the high vulnerability category and are dominant in coastal areas as in Ciwandan and Anyer Districts, which are directly adjacent to the sea. The highlands in the study area are in Pulomerak District, Mancak District, and Waringinkurung District, with altitudes between 100 and 714 metres above sea level. Soleman et al. (2012) stated that areas potentially vulnerable to tsunamis are assumed to be coastal areas with an elevation of less than 25 metres above sea level. Therefore, for the land elevation parameter, Ciwandan and Anyer Districts are vulnerable to the tsunami disaster because the land elevation in these areas ranges from 0 to 25 masl.

Figure 3. Land elevation vulnerability level map.

In general, the west coast of Banten, which is directly adjacent to the sea and has a low elevation, makes the tsunami vulnerability level in this region higher than in other areas that are not directly adjacent to the sea. The lower the land elevation of an area, the greater the level of vulnerability to a tsunami disaster (Oktariadi, 2009).

3.2. Land slope

The slope of the land is a measure of the slope’s steepness relative to the flat surface. In general, the slope of the land is expressed in degrees (º) or percent (%). In this study, the slope of the land is expressed in percent (%). The results of mapping the slope of the land in this study are shown in Figure 4. The slope of the land is divided into five categories of vulnerability: very high (0–2%), high (2–5%), medium (5–15%), low (15–40%), and very low (>40%).

Figure 4. Map of the level of vulnerability of the slope.

The land slope affects coastal areas’ vulnerability to tsunami disasters. When a tsunami arrives on a steep coast, it will not go too far inland because it is stuck and will be reflected back by the coastal cliffs. Meanwhile, on a sloping coast, a tsunami can hit freely for several kilometres inland (Subarjo & Ario, 2015). So, in the study area, the greater the slope of the land with a slope value of > 40%, the safer it will be from a tsunami disaster compared to areas with a slope of 40%.

3.3. Land use

Land use is one of the tsunami vulnerability factors related to human intervention. According to Marfai (2011), most coastal areas are characterised by dynamic and complex (multi-function) land use. This complex land use is one of the reasons why coastal areas are prone to disasters.

Figure 5 shows that land use on the west coast of Banten consists of 10 types of land use (land use), namely reeds and meadows, lakes and situs, forests, plantations, settlements, swamps, rice fields, shrubs, rivers, and moors and fields.

Figure 5. Map of land use.

A tsunami disaster that hits an area can cause land changes in that area. Therefore, it is necessary to look at the level of land use vulnerability to the tsunami disaster. Mapping the level of land use vulnerability on the west coast of Banten is shown in Figure 5. The map of land use vulnerability on the west coast of Banten shows that the research location belongs to the category of very high vulnerability to the tsunami disaster in terms of the land use type parameter (land use). This is because land use in the area is mostly residential and paddy fields. The very high vulnerability category includes Anyer District, Ciwandan District, Jombang District, Bojonegara District, and Kramatwatu District.

3.4. Distance from the coastline

In this study, the distance from the coast was made at least 500 metres inland, referring to the research of Faiqoh et al. (2013). Mapping the distance from the coastline is shown in Figure 6. The maps shows that the area coloured solid red is at a distance of 500 metres from the beach. The closer an area is to the sea, the higher the vulnerability and risk of the area to a tsunami disaster (Diposaptono and Budiman, 2006).

Figure 6. Map of the distance from the coastline.

The western coastal areas of Banten included in the category of very high vulnerability to the tsunami disaster are Anyer District, Ciwandan District, Grogol District, and Pulomerak District. This is because land use in the district ranges from 500 metres to 1000 metres from the coast. Land use in the area is residential, rice fields, and plantations, which have a low level of protection against the tsunami disaster. Therefore, there is a need for better spatial planning to reduce the risk of a tsunami disaster. Areas included in the very low vulnerability category are far from the coastline of > 3000 metres, namely Mancak District and Waringinkurung District. According to Santius, this is because the height of the tsunami waves will decrease as the distance increases when the waves are on the shoreline.

3.5. Distance from the river

The parameter of distance from the river (river border) is also an important parameter in determining the level of vulnerability of an area to a tsunami disaster. This study set the river border parameters at least 100 metres apart along the river flow. In general, a tsunami that crosses a river will cause great damage. In a narrow area such as a river, there will be an increase in the speed and height of the water level because, with the discharge of the same mass of water, it must travel through a narrow gap at the same time (Pedersen & Glimsdal, 2010). Mapping the distance from the river is shown in Figures 7. Figure 7 shows that the western coastal area of Banten has only one major river, i.e. Cikohot river. The river is in the Suralaya Village, Pulomerak District, which is included in the category of very high vulnerability to the tsunami disaster. This is because, in large rivers, tsunamis can enter land further in areas close to rivers compared to areas far from rivers (Mardiyanto et al., 2013). Therefore, spatial planning for densely populated settlements with important economic areas should be built relatively far distance from the river, i.e. >500 metres from the river.

Figure 7. Map of the distance from the river.

3.6. Analysis of the level of vulnerability of the region to the tsunami disaster

The analysis of the level of tsunami vulnerability was carried out using the overlay method for all parameters contained in the analysis matrix of the level of tsunami vulnerability (Table 2). The classification of tsunami vulnerability levels on the west coast of Banten consists of five categories: very high, high, medium, low, and very low. A map of the level of vulnerability on the west coast of Banten is shown in Figure 8.

Figure 8. Map of the level of vulnerability of the west coast of Banten to the tsunami disaster.

Areas with very low and low vulnerability categories for the tsunami disaster, namely:

1. Waringinkurung District

2. Mancak District

3. Pabuaran District

4. Bojonegara District

5. Pulomerak District

6. Puloampel District

The land elevation in the area is at an altitude of > 100–714 masl with a slope of > 40%, so the area is included in the very low vulnerability category.

The medium vulnerability category is in an area with a distance of 1500–3000 metres from the coastline. Areas included in the medium vulnerability category for the tsunami disaster were:

1. Ciwandan District,

2. Anyer District

3. Kramatwatu District,

4. Cibeber District,

5. Jombang District, and

6. Bojonegara Sub-District.

Land elevation in the area ranges from 10–25 masl with a slope of 5–40%. Areas included in the high vulnerability category are located on the west coast of Banten. The areas are at a distance of 500–1000 km from the coastline. Land elevation conditions are 0–20 masl with a slope of 5–15%. Areas included in the category of high vulnerability level were:

1. Anyer District,

2. Ciwandan District

3. Citangkil District,

4. Grogol District,

5. Pulomerak District,

6. Puloampel District

7. Bojonegara District, and

8. Kramatwatu District.

Meanwhile, areas that fall into the category of very high vulnerability are located around the Cikohot River area, Suralaya Village, and Pulomerak District. The existence of rivers or estuaries in the area has an effect on the exposure of tsunami waves, which causes the tsunami waves to go further inland. The vulnerability level of the area to the tsunami on the west coast of Banten is shown in Table 4.

Table 4. The vulnerability level of the area to the tsunami on the west coast of Banten.

No.	Vulnerability Level	Wide (Km^2)	Wide (Ha)
1	Very high	0.3356	33.56
2	high	39.2362	3923.62
3	medium	79.9940	7999.40
4	Low	102.3066	10230.66
5	Very low	47.9889	4798.89
		269.8613	26986.13

The vulnerability level of the area to the tsunami disaster is determined based on the weight calculation multiplied by the score (formula 1) for each parameter. The results of the calculations for each parameter are shown in Table 5. It can be seen that the most influential parameters in the spatial analysis of the vulnerability of the west coast region of Banten Province to the tsunami disaster are the parameters of land elevation, land slope, and land use. Furthermore, Table 5 shows that the first largest total weight value (N) is the land elevation parameter; the second is the slope of the land; and the third is land use. This is also supported by Subarjo and Ario (2015), stating that the parameter mostly influences the vulnerability of the area to a tsunami disaster is land elevation. The land elevation parameter is the most contributing parameter in the analysis of regional vulnerability to the tsunami disaster because the height of the land will be related to the height of the tsunami. If the maximum tsunami wave height that reaches the coast ranges from 4 to 24 m, then a land elevation of more than 25 metres above sea level will be safe from a tsunami disaster (Soleman et al., 2012). Therefore, the elevation of the land is very influential.

Table 5. Total value weight (N) for each parameter.

No	Parameter	Total Value Weight (N)
1	land elevation	708225
2	land slope	253040
3	land use	123075
4	distance from the shoreline	300
5	distance from the river	300

4. Conclusion

The west coast area of Banten Province, which has very high vulnerability, is around the Cikohot River in Pulomerak District, with an area of 33.56 Ha. This area can potentially experience very great damage because the tsunami waves can enter through the Cikohot River. Areas that have high vulnerability are Anyer District, Ciwandan District, Cingkil District, Grogol District, Pulomerak District, Puloampel District, Bojonegara District, and Kramatwatu District, with an area of 3923.62 Ha. This area is located at a distance of 500–1000 kilometres from the coastline. Land elevation conditions are 0–20 metres above sea level with a slope of 5–15%. Areas with a moderate level of vulnerability are Ciwandan District, Anyer District, Kramatwatu District, Cibeber District, Jombang District, and Bojonegara District, with an area of 7999.40 Ha. Land elevation conditions range from 10–25 metres above sea level with a slope of 5–40%. Areas with a low level of vulnerability are Waringinkurung District, Mancak District, Pabuaran District, Bojonegara District, Pulomerak District, and Puloampel District, with an area of 15,029.55 Ha. This area has an elevation of > 100–714 m with a slope of > 40% and is a non-densely populated area. Factors that greatly affect the vulnerability of the west coast of Banten Province to the tsunami disaster are land elevation, land slope, and land use.

Acknowledgments

The authors are grateful to the Dean of Social Science Faculty of the State University of Jakarta, Prof. Dr. Sarkadi., M.Si, and Head of Geography Study Program, Dr. Ode Sofyan Hardi, S.Pd., M.Si., M.Pd, for the facilities and permission to publish this study.

Disclosure statement

No potential conflict of interest was reported by the author(s).