Analysis of Vulnerability Population to Landslides, Selo Boyolali District

Selo district is an area prone to landslides proven to be 32 events in a period of 10 years however, has a population of 29,342 people. The population is spread on moderate landslide vulnerability to very high landslide vulnerability. The purpose of this study was to determine the distribution of landslide vulnerability in the District of Selo and determine the vulnerability of the population to landslides in the District of Selo. Research using descriptive survey methods utilizing numerical data processed through ArcGIS with scoring and overlay processing. Selo District is dominated by moderate population vulnerability to high landslides.

the elderly >60 years. Educators affect the vulnerability of the population, the higher the education of the population, the more aware they are of how to evacuate a disaster, and vice versa2.

Method
According to Nazir (1983) the descriptive survey method utilizes numerical data obtained as material for interpreting certain forms of relationships in the influence of environmental elements on observed phenomena to prove hypotheses or answer research questions that have been formulated.
using numeric data that can be processed. The method uses secondary data that is used to interpret the results. The sample population is people affected by landslides. Yunus (2010), the research sampling method uses a stratified random sampling technique because members of the population or sub-populations of these strata are used as the basis for identifying the homogeneity of the sub-populations so that researchers can treat their members as having the same opportunity to be selected as members. sample and then selected at random. Researchers have grouped classes of low landslide susceptibility, medium landslide susceptibility, high landslide susceptibility, and very high landslide susceptibility which will be processed with population data so as to produce low population vulnerability, medium population vulnerability, and high population vulnerability. Variables that will be processed in scoring are rated based on the type of classification. Each score represents the level of influence of the variable on the vulnerability of landslides and the vulnerability of the population. The results of the weighting of each parameter can be classified according to the interval and level of vulnerability shown in Table 2. Landslide Hazard level. Population vulnerability is scored for each parameter used in accordance with the population data of Selo District. Table 3. Parameters and Scoring of Population Vulnerability shows the parameters and scoring used in the population vulnerability map..   An overlay was carried out to combine the landslide susceptibility map and the population vulnerability map. The interval value used is 2, namely the population's vulnerability to high landslides and the population's vulnerability to low landslides. The overlay results are categorized using SPSS (Statistical of Product and Service Solution).

Distribution of vulnerability to landslides in Selo District
Based on Figure 1. Landslide Hazard Map of Selo District shows Selo District has 3 classifications of landslide susceptibility, namely very high vulnerability, high vulnerability, and medium vulnerability. Selo District is dominated by high vulnerability spread over its territory. Selo Subdistrict, which is prone to high landslides in the south of the area, is part of the cone of Mount Merapi which has a slope of 15-40% and uses rocky soil. The northern part of Selo District which has a slope of >40%. The land use of the area is dominated by moor, gardens, grass, shrubs. In the west of Selo District, it is prone to moderate landslides with land use dominated by rice fields. Land use as productive land in the form of vegetation will not be optimal in rainwater infiltration, especially the dominant type of soil is latosol soil with a fine texture.

Figure 1. Selo Landslide Vulnerability of Selo
Landslide susceptibility is very high with volcanic mountain landforms > 40% so it has a steep slope. The use of the land as a moor that cannot infiltrate rainwater optimally even though the soil texture is regosol with larger pores. Selo Subdistrict is an area with thick soil located in a high topography which is relatively prone to landslide threats because it has the potential to experience additional soil mass loads which generally have relatively high ability to absorb rainwater compared to rocks. The stability of slopes with loamy soils is strongly influenced by the amount of water that seeps into the slopes. Therefore, in locations where rainwater seeps into the ground in large quantities, that is where landslides occur (Priyono, 2006 Use of land as settlements, fields, gardens, shrubs/shrubs, and grass. Land use in areas with slopes dominated by 15-40% will be prone to landslides. Klakah Village is the result of volcanic deposits with latosol and regosol soil types. Rainfall of 2,000 mm/year to 3,000 mm/year, soil that has a dusty loam texture is slippery and breaks easily so that it is unable to withstand soil saturation, resulting in landslides such as in the 2016 landslides. The use of open land as dry land, paddy fields, gardens, shrubs/shrubs, and grass cannot infiltrate optimally because of loamy soil texture and volcanic ash deposits which have small pores. Hardiyatmo (2006), igneous rock which is generally formed from the formation of magma which has high pressure so that it is hard and solid. These rocks have a high capacity and are very good for supporting building foundations. The population of Selo District dominates the land use for settlements on the surface of volcanic rocks compared to other rock types. Volcanic rocks have a major problem, namely rapid weathering by wetting and drying when in contact with air from the outside so that they tend to experience landslides.
Selo District has rainfall intensity of 2,000 mm/year to more than 3,000 mm/year. Heavy rainfall causes the slopes and rocks to weaken. In the dry season, the soil becomes dry, causing cracks and cavities, however, when there is high intensity of rain, rainwater enters the soil cavity which can cause the cavity to fill with water and cause landslides. Rain with high intensity can trigger landslides because through the soil water will enter and accumulate from the bottom of the slope. Especially in the southern and northern areas of Selo District which have steep slopes. This is evidenced by the occurrence of 31 landslides in 2011-2019.
In contrast to previous researchers, Rudiyanto (2010)  Samiran village experienced landslides in its irrigation area which is located on a steep slope so that drainage functions can be carried out to keep water away from the slopes, avoid water seeping into the slopes or draining water into the slopes to the outside of the slopes so that drainage must be maintained so as not to clog or absorb water. into the ground. The village of Jrakah experienced landslides which caused material losses due to the collapse of residential areas. The settlement is on a steep slope. It is necessary to build retaining embankments for rock fall and construct buildings with strong foundations. Make strong gutters to drain rainwater so that water can be infiltrated systematically in areas that have high water absorption.
Some areas that are prone to landslides, however, there has not been a landslide occurrence, mitigation can be done to prevent the occurrence of loss of life and material. Avoiding landslide-prone areas for permanent built-up land, especially on slopes >40% in the north and south of Selo District.
According to BNPB reforestation with plants with deep root systems and proper spacing (especially for steep slopes, with a slope of >40%, the vegetation is not too dense and interspersed with shorter and lighter plants, grass is planted on the bottom. There is a vulnerability map landslides can be used as a reference to create evacuation routes and landslide early warning systems.

Vulnerability of the population to landslides
Based on Figure 2. Population Vulnerability to Landslides Selo District has 2 levels of population vulnerability to landslides, namely population vulnerability to low landslides and population vulnerability to high landslides. The population of medium vulnerability has a population vulnerability that is more resilient to landslides than the population with high vulnerability. Hizbaron (2015), states that the factors that influence vulnerability are demographic factors such as population density, population size, and population distribution. Parameters used in population vulnerability are population density, population with disabilities, population of vulnerable age, female population, and population education. People with low vulnerability have a denser population density than those with moderate population density. The denser an area will greatly affect the social vulnerability of the community.

Figure 1. Population Vulnerability to Landslides in Selo District
In addition, the number of female population is more than the vulnerability of the moderate population. According to Habibi (2013), the high ratio of the number of women in the composition of the population by gender illustrates the relatively low ability in the evacuation process. This is based on the physical condition of women which is generally considered lower than the physical condition of men so that women will be more vulnerable. The number of people aged 0-5 years and >60 years is more with lower population education. Because the population aged under five years old 0-5 years old and the elderly >60 years old if there is a landslide, they have a low ability to evacuate so they need rocks from the productive age population.
Suroteleng Village, Klakah Village, and Jeruk Village are villages that have low population vulnerability to landslides. The residents of this village have low vulnerability to landslides because they have a higher ability than other villages related to landslide disasters. The population of the village has a low population density, a low number of age groups, a smaller number of female residents, no people with disabilities, and a higher education level of the population. In addition, the vulnerability of the population to low landslides is influenced by low landslide susceptibility because Village is on a gentler slope so that they are prone to moderate landslides.
The population's vulnerability to landslides is high, namely Jrakah Village, Lencoh Village, Samiran Village, Selo Village, Tarubatang Village, Senden Village, and Tlogolele Village. The seven villages are located in areas of high landslide susceptibility and moderate vulnerability of the population. The slope of the area is between 15% to > 40% with land use dominated by settlements, fields, gardens, and rice fields so that when the rainfall intensity is high, it is not able to infiltrate optimally. The settlements of the villagers are on a steep slope so that they are more prone to landslides. The population density of the village is medium density. The high population density illustrates the high chance of loss of life and property so that it threatens the survival of the community (Hapsoro, 2015). Medium population density will be easily susceptible to landslides caused by land use as settlements so that it is dominated by closed land. The high population density of the seven villages indicates that a lot of land use as settlements is located on a steep slope so that the vulnerability of the population is high. The number of people with disabilities is higher than the three villages in the low level of vulnerability of the population to landslides. People with disabilities, female residents, and people of vulnerable age are more vulnerable because they will need help when a landslide occurs. The population of Selo sub-district who are aged >60 years who work as farmers in the fields will be more vulnerable to landslides. When a landslide occurs in the moor, the vulnerable age population will find it difficult to evacuate because of their physical limitations.
Muawanah (2017)  the population is very vulnerable in the event of a landslide so that it is necessary to organize, socialize, and distribute the population to minimize the impact of the disaster.
Vulnerable population affected by landslides can be carried out non-structural mitigation.
Non-structural mitigation in the form of increasing efforts for the population to minimize casualties.
Non-structural mitigation can be carried out according to the impact of the landslide. Population Vulnerability according to BNPB includes female population, especially pregnant women, toddlers aged 0-5 years to the elderly >60 years, and people with disabilities. Selo sub-district has a population of vulnerable age in the low and medium population vulnerability class. People aged >60 years tend to work in fields located in high landslide susceptibility areas. When an avalanche occurs, the population cannot maximize their efforts to save themselves.
Mitigation of the population can be done through several workshops, socialization, and training before landslides, during landslides, and after landslides. Landslide knowledge to residents who are vulnerable to landslide susceptibility can be done by forming small groups so that residents understand more easily. Workshops are beneficial for residents because they have the skills to quickly evaluate situations and take action initiatives to protect themselves without needing help from others.
Socialization helps residents to have a landslide anticipation plan for their families and put the plan into practice with exercises. Landslide mitigation efforts involve participating in training.
Landslide training can be in the form of training before landslides, during landslides, and after landslides so that residents know how to handle them. Self-involvement will reduce the impact of landslide losses, and indirectly will provide some understanding to the closest people about landslide mitigation.

Conclusion
Selo Subdistrict is an area located on the slopes of Mount Merapi and Mount Merbabu which has 3 landslide vulnerabilities. Landslide susceptibility parameters such as soil, geology, rainfall, land use, slope, and landform. Parameters of population vulnerability are population density, population with disabilities, age group population, female population, and population education.
1. Selo District has 3 distributions of landslide susceptibility, namely very high landslide susceptibility, high landslide susceptibility, and moderate landslide susceptibility.

2.
There are 2 classifications of population vulnerability to landslides, namely population vulnerability to moderate landslides and population vulnerability to low landslides.
Selo District is dominated by the vulnerability of the population to high landslides, except for Klakah Village, Suroteleng Village, and Jeruk Village