Sumatra Island Research Articles

Mapping the habitat distribution of horseshoe crabs (Tachypleus gigas) in Pamekasan, Madura Island, Indonesia

Abstract Horseshoe crabs, often known as Belangkas or Mimi, is one of the ancient marine faunas with protected conservation status. Horseshoe crabs are distributed in coastal waters of Indonesia of the islands of Sumatra, Java, Kalimantan, and Sulawesi, which are often caught as bycatch. Horseshoe crabs’s bloods were uniquewhich contain amebocytes as a test material for the presence of endotoxin bacteria. The purpose of this study was to identify the species of horseshoe crabs and to analyze environmental conditions, as well as the distribution of horseshoe crabs in the coastal waters of Pamekasan, Madura Island. This study was conducted in June 2023 by collecting data from crab fishers. ArcGIS was applied to delineate the distribution of horseshoe crab. The identification results showed that there was one species horseshoe crab of the Tachypleus gigas in the waters of Polagan Village, Galis District, Pamekasan Regency. The environmental condition of the waters in Polagan Village, Galis District, and Pamekasan Regency was relatively good. Habitat mapping is one way to protect these animals from the threat of extinction and support conservation efforts.

The Existence and Implementation of Customary Law in Acehnese Society Viewed from a Juridical Perspective

This research examines the existence and implementation of customary law in Acehnese society through a normative juridical approach. Aceh is a province whose capital is Banda Aceh, and is located at the northern tip of the island of Sumatra. Aceh has a long history as a center for the spread, culture and religion of Islam in Indonesia, so it is called the "Veranda of Mecca" which differentiates it from other provinces in Indonesia. Researchers use qualitative engineering research methods which aim to analyze the topics discussed and relate them to applicable cases or laws. Research findings reveal that customary law still has significant power and relevance in resolving conflicts, maintaining traditions, and regulating the social life of the Acehnese people. However, challenges in implementing customary law were also identified, including harmonization with national legal systems and social and economic changes. Therefore, this research presents a comprehensive picture of how customary law interacts with the modern legal system in Aceh and its juridical implications for Acehnese society.

Ore Characteristics and Distribution Based on Geological and Geophysical Features of the Tambang Sawah Low Sulfidation Epithermal Gold Prospect in Lebong District, Sumatra Island, Indonesia

Sumatra is recognized as one of the Indonesian islands with a big potential for mineral deposits particularly along the belt known as Neogene Sumatra gold axis. However, the publication of the gold resources is still restricted as regional/district scale maps or limited in some locations and internal company reports, hence, a detailed study on deposit scale remains limited. This study aims to document the deposit geology, ore characteristics and geophysical features of the Tambang Sawah prospect at Lebong district, Sumatra Island. The study was done by geological mapping, sampling, and analyzing of selected samples by petrographic, ore microscopic, X-Ray Diffraction, micro X-Ray Fluorescence and various geochemical analyses to identify ore characteristics. The geophysical survey was carried out using geomagnetic and induced polarization. Ore mineralization is manifested by various alteration types such as argillic, propylitic, and silicification, which suffered andesitic breccia and granite host-rocks. Gold mineralization is in the form of quartz veins with typical opening space filling textures such as colloform, crustiform, cockade, moss, comb, and brecciated. The main sulfides consist of pyrite, chalcopyrite, covelite, sphalerite and galena. Gold commonly occurs as free grains. Highest grade gold of up to 21.3 ppm is associated with colloform and cockade-crustiform quartz veins. Geophysical surveys indicate that gold mineralization is associated with low geomagnetic anomaly areas. The 3D modelling of the IP survey reveals that the ore mineralization may occur at 75m depth. Two target areas located at the northeastern and southwestern portions are recommended for a follow-up detailed exploration based on the mapped ore geology, ore characteristics, and geophysical anomalies.

On the Study of Structural Equivalency for Animal Conservation in Species-Habitat Network Form

Kerinci Seblat National Park is a combination of 17 forest groups located on the island of Sumatra. This study will discuss modeling the relationship between animals and their habitats in the form of an ecological network. The relationship between species and habitat is an essential topic in animal conservation. This relationship can be modeled as a graph called the habitat-species network, with two types of vertices: species (V^s ) or habitat (V^h ). The edge connecting a species vertex and a habitat vertex represents the species ever visiting the habitat. This study aimed to discuss three measures for describing the relationship between species and habitats: structural equivalence, Jaccard similarity, and Pearson’s correlation coefficient. Structural equivalence of a group of habitats represents the similarity of animals that visit the same habitat, the Jaccard similarity describes the percentage of habitats visited by a pair of different animals, and Pearson’s correlation coefficient shows the significance of the relationship between the two species.

Why millennials and gen Z are silently leaving their jobs? Unraveling the ‘quiet quitting’ trend

This paper investigates the phenomenon and factors that influence quiet quitting behavior that is happening in millennial and Z generation workers. Quiet quitting is employee behavior that chooses to work moderately according to the tasks that have been given. Several previous research results found that this behavior can be anticipated by increasing job satisfaction which is influenced by empowering leadership, organizational culture, and work overload. This research was designed with a survey method and using a quantitative approach. Data collection in this study used online questionnaires distributed to workers in the age range of millennial and Z generations. The data analysis technique used in this research is Structural Equation Modelling (SEM) with AMOS software. The number of samples in this study was 600 respondents. The respondents are dominated by workers on the islands of Java and Sumatra and the rest are from other regions in Indonesia. The findings of this research highlight the negative effect of job satisfaction towards quiet quitting behavior in millennial and Z workers. Another result of this study is that there is a positive effect of empowering leadership and organizational culture on job satisfaction, while work overload have a negative effect on job satisfaction. The research results are useful information for planning strategies to retain employees and provide their best performance at work. These findings are significant to measure the factors that influence job satisfaction of millennial and generation Z employees so that they do not quiet quitting or leaving the company.

ANALYSIS OF SUBSURFACE STRUCTURE OF BANDAR LAMPUNG CITY BASED ON GRAVITY ANOMALIES

Bandar Lampung City is located at the southeastern tip of Sumatra Island, an area highly prone to earthquake and tsunami disasters. Along the Sumatra Island, there are seismic faults stretching along the Bukit Barisan Mountains. In the Bandar Lampung region, one of these faults is the Panjang Lampung fault. Gravity methods are commonly used to identify subsurface structures based on variations in rock density. This study aims to identify the subsurface structure of Bandar Lampung City based on gravity anomaly modeling, both 2D and 3D models. The research consists of three main stages: data correction, data processing including spectrum analysis, moving average, second vertical derivative analysis, and subsurface structure modeling. The complete Bouguer anomalies in the study area range from 41.9 mGal to 73.3 mGal. Modeling results indicate the presence of structures such as the Panjang Lampung fault in the Northeast and a graben in the Central region, verified through SVD analysis and geological information. The existence of the Panjang Lampung fault, classified as an active fault, along with volcanic pyroclastic rocks and significant sediment layers in the central region, makes the research area potentially susceptible to the impact of amplification in the event of an earthquake disaster.

Contribution of Human Development Index and Environmental Quality to Poverty in Indonesia

Poverty has long been a national problem, which until now still shows no signs of ending. Poverty is one of the fundamental problems that is the center of attention of the government in all provinces of Indonesia. In almost all developing countries, the standard of living of the majority of the Indonesian population tends to be very low. A low standard of living can create a form of poverty. The aim of this research is to determine the influence of GRDP, HDI and Environmental Quality on Poverty in Indonesia. The type of approach in this research is quantitative. The sample in this research is data from 4 variables in Indonesia for the 2018-2022 period. The analysis method used is panel data regression. The object of research is the island of Sumatra which consists of 10 provinces. The results of data testing explain that HDI has an effect and Environmental Quality has no effect on Poverty.

Expanded description & range extension of Lycodon sidiki Wostl, Hamidy, Kurniawan & Smith, 2017 (Squamata: Colubridae)

The wolf snake species Lycodon sidiki was described based on only one specimen from Aceh Province, Sumatra, Indonesia. Herein, we report new characters and a range extension of this species based on a re-examination of eight preserved specimens deposited in the collections of the Naturhistorisches Museum Wien, Austria (NHMW). Based on the new information, we record this species for the first time from West Sumatra Province (Padang) and update its diagnostic characters. Furthermore, we provide distinguishing features from the closely related species belonging to the Lycodon fasciatus species group. In addition, we also update the key to Lycodon species in Sumatra Island.

The Effect of Health Expenditure, Education Expenditure, and Poverty on the Human Development Index in Lampung Province

The Human Development Index can be used as an indicator of successful development in a country or region. In 2023, Lampung Province's Human Development Index in 2023 amounted to 72.48 and was the lowest in Sumatra Island. This study aims to determine how much the speed of convergence of the Human Development Index between districts/cities in Lampung Province and also to determine how much influence the variables of Health Expenditure, Education Expenditure, and Poverty affect the Human Development Index in Lampung Province in the short and long term. The study used secondary data on Health Expenditure, Education Expenditure, Poverty, and Human Development Index in 13 districts/cities in Lampung Province from 2014 to 2022. The research method used is dynamic panel data regression using the Sys-GMM model. The results showed that the Human Development Index gap between districts/cities in Lampung Province decreased by 54.49% per year. The elasticity of the short-term effects of Health Expenditure, Education Expenditure, and Poverty on the Human Development Index is 9.27%, -1.52%, and -2.41%, respectively. In the long run, health expenditure, education expenditure, and poverty affect the Human Development Index by 20.38%, -3.35%, and -5.30%, respectively. Therefore, the government should continue programs in the health sector, evaluate spending in the education sector, and create poverty alleviation programs that have a significant impact.

Analysis of Sustainable Food Sector Development in the Sumatra Island

The research aims to analyze the development of food security through indicators of the sustainable food sector on the island of Sumatra in 2018-2022. Food sector indicators include the number of poor people, food inflation, rice consumption per capita, insufficient food consumption, and food insecurity. Food security indicators use the food security index. The research method is quantitative through secondary data collection with panel data analysis from cross section results of 10 provinces on the island of Sumatra and time series data for 2018-2022. The approach used, namely CEM,FEM, REM. The research findings show that the food inflation variable has a positive and significant effect on the food security index, the poor population variable, rice consumption per capita, insufficient food consumption has a positive and insignificant effect on the food security index. Population with food insecurity has a negative and insignificant effect on the food security index.

Extreme founder effect associated with hyperglycemia and hyperlipidemia on the island of NIAS/Indonesia

The island of Nias/Indonesia shows an extremely reduced genetic diversity indicating a strong founder effect. As a consequence, the prevalence of some disease genes should significantly differ among populations depending on the gene pool passed on to the founder population and their successive expansion as it has already been documented for several monogenic diseases. Results of the current study based on routine laboratory blood examination give rise to the notion that this might also hold true for polygenic disorders. We observed very high prevalence of hyperglycemia (non-fasting glucose above 200 mg/dL in 14 % Nias population compared to 1.5 % in the population of the neighboring island of Sumatra) accompanied by hypertriglyceridemia, high non-HDL-cholesterol, and low HDL-cholesterol levels. These findings suggest that the Nias population may be disproportionally affected by prediabetes and type 2 diabetes mellitus. By contrast, laboratory parameters potentially indicative of other polygenic disorders such as total plasma cholesterol, electrolytes, creatinine, urea, and uric acid were comparable between the inhabitants of Nias and Sumatra islands. To our knowledge this is the first study suggesting that the extremely strong genetic bottleneck seen in the Nias population translates into the widespread metabolic disease with potentially deleterious influence on public health.

Structural Transformation of the Agricultural Sector and Influencing Factors in Sumatra Island

The objective of this research is to determine whether there has been a transformation in Sumatra Island during the period from 2010 to 2022 and to identify the influencing factors. The data utilized in this study is secondary data obtained from official sources such as the Central Statistics Agency. The collected data includes Gross Regional Domestic Product (GRDP), poverty rate, open unemployment rate, investment data, and average years of schooling. The findings reveal that over the 12-year period, Sumatra Island did not experience a significant transformation, despite the agricultural sector being its primary contributor. The island only underwent a shift of 0.62, a value smaller than that of the mining sector. The factors influencing the shift in the agricultural sector in Sumatra Island include the unemployment rate, poverty rate, investment, and average years of schooling.

Surface deformation monitoring and forecasting of sinabung volcano using interferometry synthetic aperture radar and forest-based algorithm

The Sinabung volcano on Sumatra Island stands out as one of the most active volcanos, having recorded the highest number of eruptions since it resumed activity in 2010. The eruptive activities have caused significant deformations on the volcano's surface. This research aimed to analyze, cluster, and forecast its deformation patterns based on Sentinel-1 A time series data from 2016 to 2023. The differential interferometry synthetic aperture radar (DInSAR) technique was used to monitor monthly deformations and to create time series data. A forest-based forecast (FBF) model was used to predict the rate of changes in volcano surface inflation from January 2024 to December 2027. The deformation times series patterns were also analyzed and clustered into three regions to reveal areas with similar deformation behaviors. The results indicated that Mount Sinabung's deformation is an overall continuous sporadic phenomenon where random ground inflation and deflation were recorded throughout the area with an average deformation rate ranging from 0.06 to 0.32 cm/month and an overall average of 0.197 cm/month with a standard deviation of 0.96 cm, confirming that the volcano is inflating. The highest single-pixel monthly inflation of 4.62 cm was recorded in 2023, while the highest deflation occurred in 2018 at −4.58 cm. The FBF model predicted a gradual and increasing inflationary pattern at the rate of 0.54 cm/month for 2024–2027, higher than the average of the observed data. The deformation within the lava dome and caldera poses a significant risk and could lead to wall collapses and landslides in the crater dome, potentially triggering explosive eruptions. The outcomes of this research serve as valuable supporting information and offer an early warning of potential volcanic disasters in the future.

Analyze QRF model for soil organic carbon map building with digital soil mapping (case study: Sumatra island and Java island)

Abstract In the current era of global warming, soil organic content is one of the most important soil properties. The goal of the entire globe is for carbon neutrality to be achieved and regularly assessed. It is hoped that a dynamic, quick and effective soil organic carbon mapping method will be able to distribute the presence of soil organic carbon to support calculations for changes in carbon stocks and carbon sequestration so that carbon neutrality can be achieved. Digital Soil Mapping (DSM) recently has become the ultimate framework for accurately representing spatial distribution based on its quantitative result and uncertainty analysis. These advantages allow DSM to be replicated uniquely in each mapped area. Digital soil mapping requires input in the form of laboratory and field observation results that are spatially modeled using machine learning techniques. Field observations and laboratory data for Sumatra and Java Island from the Indonesian Center for Agricultural Land Resources Standard Testing (1970-2022) were used in this study, and the results were modeled using Quantile Regression Forests (QRF) in the R Software. Evaluation results from this model with 5738 observation points covering a 47.3 million-hectare-sized island of Sumatra and 3398 observation points covering a 12.8 million-hectare-sized island of Java show an RMSE value of 0.78 with a coefficient of determination (R2) of 0.31 for Sumatra Island and RMSE value of 0.68 with a coefficient of determination (R2) of 0.71 for Java Island. These findings indicate that the neighborhoods for the organic carbon content on the islands of Sumatra and Java differ quite noticeably. This may be due to the relatively wide range in some soils in the Sumatra region, which are peat soils with relatively high carbon content values compared to regions in Java where mineral soils predominate. In conclusion, the evaluation results for digital mapping with the QRF model for soil organic carbon content in Indonesia referring to these 2 large islands show good results with sufficient coefficients of determination in mineral soil areas and there is a need a different modeling approach in areas where peat soil predominates.

ESTIMATION OF EARTHQUAKE INSURANCE PREMIUM BY CONSIDERING EARTHQUAKE PROBABILITY AND THE DAMAGE RATIO OF BUILDINGS IN BANDA ACEH AND SIBOLGA CITY

Indonesia is one of the countries prone to earthquakes with significant damage. An area that is frequently hit by earthquakes is Sumatra Island. Several cities, such as Banda Aceh City and Sibolga City on Sumatra Island, quite often experience tremors. For this reason, mitigation efforts are needed through earthquake insurance in managing disaster risk in earthquake-prone areas such as Banda Aceh City and Sibolga City so that it can reduce the impact caused by earthquake disasters. This research aims to determine the probability of an earthquake occurring in Banda Aceh City and Sibolga City using the Probabilistic Seismic Hazard Analysis (PSHA) method. Apart from that, this research also aims to determine the value of the building damage ratio and the estimated value of pure earthquake insurance premiums in Banda Aceh City and Sibolga City. The analysis results show that the estimated pure premium value for residential commercial and industrial building types with less than nine floors in Banda Aceh City is around 2.96 and 21.03 times greater than that of Sibolga City. Meanwhile, the estimated pure premium value for commercial and industrial building types with more than nine floors in Banda Aceh City is more minor, around 6.42 times, compared to Sibolga City.

Groundwater quality assessment in different volcanic rocks using water quality index in the tropical area, Indonesia

Groundwater is the main water source that is most widely used in the world, one of which is in Indonesia. One of the uses of groundwater is for consumption needs. Therefore, the groundwater used should have good water quality. For this reason, this study aimed to determine groundwater quality in Indonesia during the dry season and make recommendations for groundwater management policies. A total of 211 groundwater samples taken from springs, drilled wells, and dug wells spread across volcanic areas on the islands of Sumatra, Java, Bali, and Sulawesi were collected to test their quality in this research. The method used in this research consisted of 4 analyses: WHO threshold analysis, Piper Diagram, Water Quality Index (WQI), and statistical correlation and regression. Based on the analysis, it was discovered that 47 K+ samples, 1 Na+ sample, 5 Ca2+ samples, 1 Cl- sample, 115 HCO3- samples, 3 TDS samples, and 3 pH samples exceeded WHO standards. The results of the Piper triangle diagram analysis showed that the majority of groundwater in Indonesia falls into the Unpolluted Groundwater classification (categories D and G), and the results of the WQI analysis also showed that 98% of the groundwater in Indonesia analyzed falls into the excellent and good water categories. The results of statistical analysis of the parameters K+, Na+, Mg2+, Ca2+, SO42-, Cl-, HCO3-, TDS, and pH showed that all these parameters are strongly and positively correlated with the WQI value.

NEW DISTRIBUTION RECORD OF Opisthostoma platycephalum (CAENOGASTROPODA: DIPLOMMATINIDAE) FROM PADANG BINDU KARST, SOUTH SUMATRA, INDONESIA

A fauna expedition has been conducted in Padang Bindu Karst, South Sumatra in 2021. Among the collected samples, a total of 111 specimens of Opisthostoma platycephalum (Caenogastropoda: Diplommatinidae) were collected from five sampling plots. This discovery is the first record of the land snail species in the southern of Sumatra island, as previous research only recognized its presence in Aceh, North Sumatra, and Peninsular Malaysia. This discovery contributes to the understanding of the biodiversity of South Sumatran land snails and highlights the importance of protecting limestone habitats.

FAKTOR-FAKTOR YANG MEMPENGARUHI PENYERAPAN ANGGARAN PADA PEMERINTAH PROVINSI DI PULAU SUMATERA

This research was conducted in order to achieve the goal of understanding the Factors Affecting Budget Absorption in the Provincial Government on the Island of Sumatra. The data utilized is data that is already available in the Audit Report sourced through the BPK RI website and Regional Regulations on the BPKAD website in provinces on the island of Sumatra. The population that is the focus of this research includes all provinces on the island of Sumatra with a total of 10 provinces on the island of Sumatra for the 2018-2022 fiscal year and the sampling method used is a comprehensive sampling method or saturated sampling with an observation unit of 50 samples. Data processing involves assistance in the form of the Eviews version 12 application. The results of this study indicate that partially Fiscal Stress does not affect Budget Absorption while Budget Setting Time partially affects Budget Absorption. Simultaneously Fiscal Stress and Budget Setting Time affect Budget Absorption

Does the Manufacturing Industry Reduce Poverty on Sumatra Island?

Poverty alleviation is an important priority for governments. Encouraging manufacturing growth is often seen as an effective strategy to alleviate poverty. However, the impact of such growth on poverty rates in Sumatra Island remains unclear. This study analyze the impact of manufacturing growth on poverty rates in 10 provinces in Sumatra Island, using secondary data from 2008 to 2022. Using the quantitative approach and panel data regression analysis, the results show that industrial growth in Sumatra Island, although not significant, has an impact on poverty reduction. However, industrial growth can indirectly absorb labor. Labor and education variables have a negative and significant effect on poverty. These findings highlight the need for policy interventions focusing on vocational education and training, infrastructure improvement, economic diversification, labor policies, and local community empowerment to effectively reduce poverty.

Board Game Introduction of Jukung Palembang Boats for Adolescents Aged 17-25 Years in the City of Palembang

South Sumatra with its capital city Palembang, is part of the island of Sumatra which has an area of 91,806.36 km2. because it is fed by many rivers, the mobility and needs of the people in the South Sumatra Province are basically very dependent on the main rivers, namely the Musi River and its tributaries. Many traditional ships pass through the Musi River, one of which is the Jukung ship which is usually one of the transportation used by the community to travel from one region to another and is also used to transport staples or trade goods and agricultural products. The design of the introduction of the Jukung ship is one of the preservation efforts to increase understanding in adolescents and the community. In overcoming these problems, the author uses the design thinking method for data collection and data analysis through the 5W+1H method (what, why, who, where, why, how), so as to produce an idea that can be applied at the design stage. The designed works are categorized into three media, namely issue media including, posters, x-banners, main media in the form of board games, and supporting media including, t-shirts, miniature Jukung ships, totebags, stickers, puzzles, pencil pouches, key chains. The application of the media uses illustrations of Jukung ships, rivers, ampera and other supporting elements, it is hoped that this design can embrace teenagers.