Sulawesi Research Articles

ANALYSIS OF DETERMINANTS OF THE HUMAN DEVELOPMENT INDEX ON THE ISLAND OF SULAWESI (2010-2022)

This research aims to analyze the factors that influence the Human Development Index (HDI) on Sulawesi Island in 2010-2022. This research uses multiple regression analysis with the Human Development Index as the dependent variable, while the open unemployment rate, poverty and capital expenditure as independent variables. The data source in this research is secondary data in the form of data on the open unemployment rate, the number of poor people and the realization of capital expenditure. The results of this research show that the open unemployment rate variable and the capital expenditure variable have a positive and significant effect on the Human Development Index variable on Sulawesi Island in 2010-2022. Meanwhile, the poverty variable shows that the results have a negative and significant effect on the Human Development Index variable on Sulawesi Island in 2010-2022. It is hoped that the government of each province on the island of Sulawesi can create policies that are more effective in increasing the human development index in their regions, namely reducing the level of open unemployment by creating more job opportunities, so that the number of poor people decreases and can get better education and health facilities. Good. Furthermore, the government of each province on Sulawesi Island is expected to be able to utilize all the resources it has in order to have maximum regional income and be able to realize each regional budget appropriately and effectively in order to accelerate the development of their respective regions.

Paleoweathering and Detrital Provenance of Balangbaru Shale, in South Sulawesi

Sulawesi Island, known for its geological complexity, offers a unique opportunity for researchers to investigate further into sedimentary basins particularly in South Sulawesi area. The Cretaceous Balangbaru Shale is one of the rocks that has an extensive distribution in South Sulawesi especially in the western part. Due to limitation of geological information related to this formation we performed the paleodepositional investigation to elucidate the paleoweathering, geochemistry characterization, and detrital provenance of the Balangbaru Shale. Indeed, previous studies have demonstrated that fine-grained sedimentary rocks can serve as valuable archives of geochemical information, enabling the reconstruction of paleoclimate evolution during the deposition period. Employing XRF quantitative analysis, we examine the dispersion of major elements within eight distinct layers of the Shale. Additionally, comprehensive whole-rock analyses enable us to ascertain the abundance of major elements and subsequently deduce detrital SiO2 and biogenic SiO2 content, thereby comprehending the inorganic geochemical composition of the Balangbaru Shale.The present study seeks to address the limited understanding of the geochemical properties of the Balangbaru Shale, specifically pertaining to paleoweathering intensity and detrital provenance. Acknowledging the scarcity of recent data available on the subject matter, this research aims to bridge the limitation data gap by conducting an in-depth investigation into the geochemical characteristics of the Balangbaru Shale by employing major oxides concentrations (SiO2, Al2O3, Fe2O3, K2O, P2O5, MgO, CaO, Na2O, MnO, TiO2, Cr2O3) and trace elements (Sr, Cu, Ba, Th, Ni, V, Th, U) into the equations such as C-value, chemical index alteration (CIA), plagioclase index of alteration (PIA), weathering index of parker (WIP) and ratio of Rb/Sr, U/Th, Sr/Cu, Sr/Ba. Furthermore, the major oxides ratio of Al2O3/TiO2 and TiO2/Zr were performed to specify the sediment provenance and the source-area rock compositions of the Balangbaru Shale. The obtained data reveals a moderate to high degree of weathering intensity in the detrital source environment of the Balangbaru Shale, suggesting warm to humid climate conditions in the source region. Additionally, the analysis of the detrital fraction indicates the possible origin of the Balangbaru Shale from felsic rocks. Overall, these findings contribute significantly to the understanding of paleoenvironmental conditions associated with the Balangbaru Shale, shedding light on its geological history.

First photograph record of the segura’s throatspine gudgeon Belobranchus segura Keith, Hadiaty & Lord 2012 in the south of Java, Indonesia (Teleostei: Gobiiformes: Eleotridae)

Segura’s Throatspine Gudgeon Belobranchus segura Keith, Hadiaty & Lord 2012 is an amphidromous fish from the Indo-Pacific region. In Indonesia, B. segura was distributed in Papua, Halmahera, Sulawesi (previously known as Celebes) and Java Island. The finding of this species in the lower stream river of Malang district, south of Java, Indonesia, was firstly recorded here. This study provides the photographs of a single male specimen of B. segura, the description of morphological features of a specimen and their habitat conditions.

Population Abundance of Macaca fascicularis and potential human-wildlife conflicts in Bonerate and Kalao Island

Recently, conflicts between human and wildlife have emerged more frequently with high escalation and widely spread due to increasing human population growth, agriculture expansion, land conversion, infrastructure development, and climate change. Raising conflicts were prominent between human and primates. The long-tailed macaque, M. fascicularis is known to face conflicts in many areas in Indonesia. The species is also found on Bonerate Island and Kalao Island nearby one of Wallacea hotspots the island of Sulawesi. This research aims to: (1) monitor the population of M. fascicularis in relation with its influences to potentially creating conflicts and (2) identify conflicts between human and the macaques through perceptions of people inhabited Bonerate and Kalao Islands. Population data was collected by observing the M. fascicularis habitat by using the concentration count method to estimate population density. To identify conflicts, data on public perceptions of M. fascicularis was collected by interviewing local people of the two islands. The research results showed that the number of individuals M. fascicularis found on the observation route was 1,064 individuals in an observation area of 54.46 Ha at Bonerate Island and 618 individuals in an observation area of 66.02 Ha at Kalao Island. The population density value of M. fascicularis is 20 individuals/ha in Bonerate Island and 9 individuals/ha in Kalao Island. There were conflicts emerged between the community and long-tailed monkeys in Bonerate Island and Kalao Island. The community perceived the long-tailed monkeys as pests or enemies that had to be exterminated. There is a need to resolve the conflict between the people of both islands and long-tailed macaques through persuasive efforts to control the long-tailed macaques population.

Noise and site response characterization in Makassar Strait and Celebes Sea based on Ocean Bottom Seismometer

To overcome the limited information in the northern waters of Sulawesi Island, ocean bottom seismometers (OBS) were installed in the northern part of the Makassar Strait and the Sulawesi Sea. OBS data were analysed using passive seismic methods to determine the characteristics of noise and site response in the Makassar Strait and the Celebes Sea. Probabilistic Power Spectral Density (PPSD) from OBS station showed microtremor in the period 0.06 – 0.7 s, secondary microseismic peak in the period 0.9 – 2 s, secondary microseismic peak in the period 4 – 8 s, and hum in the period more than 10 s. The amplitude of the noise power is in the range of New Low Noise Model (NLNM) and New High Noise Model (NHNM) for a period <10 s and slightly above NHNM for a period >10 s for OBS IGGCAS F-type. For OBS IGGCAS G-type, the noise power amplitude is in the period < 0.7 s in the NLNM and NHNM ranges. However, there is a tendency for the noise power amplitude to be flat with an amplitude above NHNM for a period > 0.7 s. The noise power’s amplitude depends on the station’s location, climate, instruments, daily variations, and seasonal variations. Horizontal-to-Vertical Spectral Ratio (HVSR) in the North Makassar Strait shows an H/V curve with an unclear peak in the middle of the strait and multiple peaks in the eastern part of the strait with a frequency range of 1.35 – 4.7 Hz. Between the Makassar Strait and the Celebes Sea, the H/V curve shows a flat peak and multiple peaks with a frequency range of 1.10 – 4.03 Hz. Meanwhile, in the Celebes Sea, the H/V curve shows an unclear peak (unclear peak) and several peaks (multiple peaks) with a frequency range of 0.65 – 6.25 Hz.

PELATIHAN PEMBUKUAN SEDERHANA PADA PELAKU UMKM DI DESA SALAKAN SULAWESI TENGAH

The aim of this community service activity is to increase the understanding and knowledge of MSME players regarding simple bookkeeping, which includes recording cash books, calculating profit/loss, and separating personal money from business money. The implementation of simple bookkeeping training is aimed at MSMEs, namely TRI AL FAEYZA and AKBAR LAUNDRY. This service was carried out for approximately 30 days at Salakan Banggai, Central Sulawesi Islands. The method used is training and counseling. The activity was carried out in August 2023. As a result of this service activity, MSMEs better understand and know the importance of keeping simple bookkeeping, which includes recording cash books, calculating profit/loss, and separating personal money from business money. As well as the risks that will occur if you do not implement simple bookkeeping

Paleoseismic Analysis of the Walanae Fault Zone in South Sulawesi, Indonesia

The most seismogenic fault of South Sulawesi region is Walanae Fault, which has a moderate seismicity history with magnitudes ranging from Mw 4 to Mw 5. The largest earthquake occurred in 1997 with a magnitude of Mw 5.9. After the Donggala-Palu earthquake assailed Sulawesi Island in 2018, the fault in this region were reactivated, including the Walanae Fault system that has pair parallel faults, West Walanae Fault (WWF) and East Walanae Fault (EWF). This fault zone has a 150-km-long and 3-km-wide fault traces, and should have seismicity potential to produce larger earthquakes than the events measured to date. The resulting radiocarbon ages obtained from the dating of organic samples collected on two tranches along with the EWF support that the Walanae Fault zone has a longer earthquake history in the ranges of 4,000 BP (3,050 cal BP and 3,990 cal BP) and 100-300 AD (101 AD pMC and 340 cal BP). The results of age evidence suggest that the Walanae Fault system is an active fault, and must remain of concern as an earthquake source with potential hazards in the region, comprising the West Walanae Fault (WWF) and the East Walanae Fault (EWF). Both faults are separated by a narrow lowland area of Walanae Depression (25 km). The lowland area sandwiched by these two faults harboring a potential seismic amplification that might be generated by thick sediment filled the lowland. Keywords: seismicity, earthquake, radiocarbon dating, Walanae Fault

Jurassic-Paleogene spreading history of the northern Indian Ocean as a constraint on the evolution of the north Australia continental margin

The spreading history of the northern Indian Ocean is re-examined with the aim of interpreting the late Mesozoic-Paleogene evolution of the northern Australian continental margin in eastern Indonesia and Timor-Leste. The earliest seafloor spreading (‘Argo phase’) developed between approximately 155-131Ma (Kimmeridgian, Late Jurassic to Valanginian, Early Cretaceous). A clockwise pole of rotation relative to Australia (‘Argo pole’) is interpreted at 7°09’S, 133°07’E, a present-day location near the Tanimbar islands in eastern Indonesia. A second ‘Gascoyne’ phase of spreading, between 131-100Ma (late Early Cretaceous), had an interpreted clockwise rotation pole at 3°40’N, 125°00’E, a present-day location between the islands of Mindanao (southern Philippines) and Sulawesi (eastern Indonesia). A third ‘Wharton’ phase of spreading, commencing at the beginning of the Late Cretaceous (~100Ma) had a more distant pole (clockwise pole at 5°S, 171°E: Jacob et al., 2014), although more local rotations are interpreted for the Greater Sula Spur continental terrane, about a pole estimated at 9°24’S, 134°40’E, close to the earlier Argo pole.The motions of two continental terranes are inferred from the spreading history. The Argoland Terrane, which is identified in this study as eastern Sundaland (Borneo and Java), would not have entirely detached from Australia before the mid Cretaceous due to the relatively proximal locations of the Argo and Gascoyne rotation poles. In this scenario Argoland could not have collided with Eurasia in the Cretaceous, as suggested by several previous studies. The Greater Sula Spur Terrane (several continental fragments in present-day eastern Indonesia), is repositioned in the initial reconstructions immediately north of Timor, and did not move northward to its late Paleogene (pre-Neogene collision) location until the Wharton phase of rifting that commenced in the Late Cretaceous. This northward motion of the Greater Sula Spur was accommodated by the development of a narrow oceanic basin (the Banda Embayment).The reconstructions suggest that the Argoland and Greater Sula Spur continental terranes formed a continuous crustal connection between SE Asia and northern Australia throughout the late Mesozoic and early Paleogene, and that the Indian Ocean developed entirely within the body of the disrupting Gondwanaland supercontinent, rather than linking eastwards into the Pacific Ocean.

Identifying Linguistic and Speech Acts Variations of the Buginese Tribe Through Socio-Pragmatic Analysis in Establishing Daily Discourse Interactions

Buginese is a local language in South Sulawesi, Indonesia, which is spoken in almost 60% of Sulawesi Island. This study aimed to explore the selection of linguistic variations and language acts as a linguistic model used by ethnic Buginese in establishing discourses of everyday socio-pragmatic interactions. It relied on a qualitative design to obtain the linguistic corpus that occurs empirically and naturally in communication interactions. This study used the snowball method by combining ethnographic strategies. The instrument used the Speaking Involvement Technique, in which the researchers were directly involved in people’s interactions by paying attention to communicating situations, recording data, and conducting interviews for data validation purposes. All data or corpus of linguistic variations and speech acts collected were analyzed by the speaking strategy componential technique strategy developed by Dell Hymes. This study successfully discovers a model for identifying the Buginese ethnicity's linguistic variations and speech acts to build a discourse of communication interactions. The expressions of selection of linguistic variations and speech acts are dominantly based on polite sentence constructions and formulations, and ethically according to the local culture of Buginese ethnicity, namely the culture of siri. The results of this study can affect the enrichment of scientific information, which functions and acts as a meaningful reference in the field of linguistic studies, especially examining speech act variation in the expression of conversational discourse, in addition to being a foundation in the development of local content material and multicultural understanding.

APLIKASI DOUBLE DIFFERENCE UNTUK IDENTIFIKASI ZONA PATAHAN MIKRO WILAYAH SULAWESI BARAT

West Sulawesi is an area in South Sulawesi province that is experiencing a sudden increase in seismic activity. There have been 264 earthquake events recorded during the 2021-2022 period. The increase in seismic activity occurred around the west Sulawesi segment and the Mamuju segment, which are local faults located in west Sulawesi. Sulawesi Island itself is the result of fragments due to larger complex reactions and has quite high seismic activity. Therefore, it is necessary to calculate the earthquake hypocenter relocation to obtain more accurate hypocenter parameters for fault zone identification and micro fault orientation. This study aims to relocate the earthquake hypocenter based on mathematical measurement data using the Double-Difference method for identification of fault zones and micro-fault orientation. The data used is BMKG earthquake catalog data for the western Sulawesi region with a range of 118.49 East - 119.59 East and 3.67 LS -2.45 LS in the 2021-2022 period. The Double-Difference method is a method based on the Geiger method using residual travel time data from each pair of hypocenters to the earthquake recording station. The principle is to compare two earthquake hypocenters that are close to the earthquake recording station with the assumption that the distance between the two hypocenters must be closer than the distance between the hypocenter and the earthquake recording station. This is done so that the raypath of the two hypocenters can be considered close to the same value. From the calculation of the earthquake hypocenter relocation, it was found that the hypocenter after relocation experienced changes in distribution that accumulated in the Mamasa fault segment area. From the residual histogram, it is found that the RMS residual is close to 0, indicating an improvement in data quality as evidenced by the observation travel time and the calculated travel time are almost close to the same value. In the cross-section results, it is obtained that the depth changes vary in the subsurface depth from the initial depth of 10 km before being relocated, indicating that the earthquake that occurred in West Sulawesi was included in the shallow crustal earthquake type.

Distribution of Ground Temperature in the Geothermal Manifestation Area of Lompio, Donggala Regency, Central Sulawesi Province

The distribution of non-volcanic geothermal energy is widely found on the island of Sulawesi, one of which is in Lompio Village, Sirenja District, Donggala Regency, Central Sulawesi Province. It is important to study the geothermal potential in the village in order to learn how the geothermal system works. This study aims to identify the distribution pattern of temperature distribution in shallow soil depths as a manifestation of the geothermal system below the surface and its relation to geothermal manifestations that appear on the surface. This research was carried out through a series of field observations and direct soil temperature measurements in the study area using a thermometer. The results show that the distribution pattern of land temperature distribution in the high-temperature zone is associated with the presence of geothermal manifestation points on the surface (hot springs). The association of temperature and manifestation is possible because the presence of hot springs is an indication of a weak zone for the release of hydrothermal fluid from the geothermal system, which is correlated with the geological structure in the research area.

PERANCANGAN RUMAH TINGGAL MENGGUNAKAN KONSEP HEMAT ENERGI

Indonesia, with a population of 275,773.8 million people, faces challenges in providing adequate housing. Electricity demand will reach 1,172 kWh per capita in 2022, dominated by fossil energy. The National Energy Council (DEN) seeks to increase the contribution of new renewable energy (EBT) to 25.9% by 2025. Sulawesi Island has various traditional houses, such as Tambii, Tongkonan, Walewangko, Mandar, and Dulohupa. Gorontalo City as the capital of Gorontalo Province has solar energy potential that has not been utilized optimally, especially in residential homes, due to the high price of solar panels. Gorontalo, with its hot climate, can utilize solar energy through solar panels to reduce dependence on conventional electricity. Awareness of energy sustainability and public education regarding renewable energy technology, especially solar panels, are very necessary to create efficient and environmentally friendly homes in line with the objectives of the National Energy Policy.

Seasonal potential fishing zone model in the regional fisheries management of Indonesia (WPP-RI) 716 based on remote sensing satellite data

The variability of atmosphere-ocean interactions highly influences the distribution of fishing zones in the surrounding Indonesia Through Flow (ITF) channel, such as the WPP-716 region. Therefore, the seasonal determination of the fishing zone is crucial in this zone as one of the regional fisheries managements in Indonesia. This study aims to create a potential fishing zone (PFZ) model in the Regional Fisheries Management of Indonesia (WPP-RI) 716 based on the remote sensing satellite data. This study used the daily SST data extracted from the Suomi-National Polar-Orbiting Partnership-Visible Infrared Imaging Radiometer Suite (SNPP-VIIRS) image Level 2 from 2018 to 2019. A Single Image Edge Detection (SIED) method is applied to determine the PFZ points. Supporting data, such as sea current patterns, chlorophyll-a, fish-catching zones and Catch per Unit of Effort (CpUE), are also considered to bolster this study's findings. The models were validated and compared with the results established by central authority fish catch data. Of particular concern, the highest detection of PFZ is observed during the second transitional season, reaching 1835 points scattered all over the study area. The frequently detected PFZ is identified in northern Sulawesi and Sangihe Islands, where the circular eddy current observed during the second transitional season, ranging from 0.6 to 0.8 m/s, indicating upwelling (high productivity) events proven by the variability of surface temperature and chlorophyll-a and aligned with the high value of CpUE (ranging from 20 to 28 ​kg/GT/day). The developed model is expected to be a basis for further decision-making regarding fishery resources management in the study area.

Spatial Analysis of Mountain and Lowland Anoa Habitat Potential Using the Maximum Entropy and Random Forest Algorithm

The Anoa is a wild animal endemic to Sulawesi that looks like a small cow. Anoa are categorized as vulnerable to extinction on the IUCN red list. There are two species of Anoa, namely Lowland Anoa (Bubalus depressicornis) and Mountain Anoa (Bubalus quarlesi). In this study, a comparison of potential habitat models for Anoa species was conducted using Machine Learning algorithms with the Maximum Entropy (MaxEnt) and Random Forest (RF) methods. This modeling uses eight environmental variables. Where based on the results of Bubalus quarlesi potential habitat modeling, the RF 75:25 model is the best algorithm with the highest variable contribution, namely humidity of 82.444% and a potential area of 5% of Sulawesi Island, with an Area Under Curve (AUC) of 0.987. Meanwhile, the best Bubalus depressicornis habitat potential model is the RF 70:30 algorithm, with the highest variable contribution, namely population of 88.891% and potential area of 36% of Sulawesi Island, with AUC 0.967. This indicates that Anoa extinction is very sensitive to the presence of humidity and human population levels.

Ghost introgression in ricefishes of the genus Adrianichthys in an ancient Wallacean lake.

Because speciation might have been promoted by ancient introgression from an extinct lineage, it is important to detect the existence of 'ghost introgression' in focal taxa and examine its contribution to their diversification. In this study, we examined possible ghost introgression and its contributions to the diversification of ricefishes of the genus Adrianichthys in Lake Poso, an ancient lake on Sulawesi Island, in which some extinctions are known to have occurred. Population-genomic analysis revealed that two extant Adrianichthys species, A. oophorus and A. poptae are reproductively isolated from each other. Comparisons of demographic models demonstrated that introgression from a ghost population, which diverged from the common ancestor of A. oophorus and A. poptae, is essential for reconstructing the demographic history of Adrianichthys. The best model estimated that the divergence of the ghost population greatly predated the divergence between A. oophorus and A. poptae, and that the ghost population secondarily contacted the two extant species within Lake Poso more recently. Genome scans and simulations detected a greatly divergent locus, which cannot be explained without ghost introgression. This locus was also completely segregated between A. oophorus and A. poptae. These findings suggest that variants that came from a ghost population have contributed to the divergence between A. oophorus and A. poptae, but the large time-lag between their divergence and ghost introgression indicates that the contribution of introgression may be restricted.

Spatial metrics of deforestation in Central Sulawesi, Indonesia

Climate change has become an environmental issue that has received the most attention because it affects all aspects of life. One of the factors causing climate change is deforestation which continues to occur, especially in tropical countries like Indonesia. Indonesia is a country that has a high rate of deforestation that occurs in large islands including the island of Sulawesi as the Wallacea Region. Central Sulawesi Province has had the largest area of deforestation among other provinces on Sulawesi Island in the last three decades (1990-2020). Analysis of the rate of deforestation using the Geographic Information System shows that the highest deforestation rate occurred in Palu City at 2.16% (1990-2020), even in the last decade (2010-2020) the rate of deforestation was 3.31%. After that, it was followed by Banggai Islands Regency at 0.17%, while other districts were at rates below 0.1% (1990-2020). Palu City and Banggai Islands Regency are also a concern, further information after the rate of deforestation is the pattern of deforestation which is described through three metrics, namely Clumpiness Index, Contiguity Mean Index, and Patch Density which describes fragmentation using Fragstat software. Palu City has a clustered deforestation pattern and is entirely connected to each deforested area, but it has lower fragmentation. Banggai Islands District has fairly clustered deforestation, but does not have low connectivity between deforested areas, and tends not to be fragmented. Dealing with deforestation incidents in Palu City as a whole land area, and Banggai Islands Regency as a separate land area is different.

Dynamic analysis of geophysical characteristics of Una-Una Volcanic Island, Sulawesi, Indonesia

The Una-Una Volcanic Island is an active and isolated island, and its deep structure and dynamic causal mechanism have yet to be fully understood. The island is situated in Tomini Bay, between the north and east arms of Sulawesi Island in Indonesia. Around 5 Ma, the Sula Islands collided with the east arm of Sulawesi Island, which caused the subduction and retreat of the North Sulawesi Trench. Additionally, a sinistral strike-slip of roughly 4 cm/a initiated at the Palu-Koro fault on the western side of Sulawesi Island, ultimately leading to the formation of the isolated Una-Una Volcanic Island in Tomini Bay. Here, we utilized gravity, seismic, magnetic, and heat flow data to calculate the geophysical characteristics of three-dimensional temperature, velocity, and viscosity of the northern Sulawesi region. The results of our research showed that the crust in the northern region of Sulawesi Island is primarily characterized by brittle deformation. However, the presence of a southward-inclined weak layer in the crust, which resulted from the subduction of the North Sulawesi Trench, caused the region between the terrain and the Moho surface to exhibit a combination of brittle and ductile deformation. The weak zone in the crust in the northern region of Sulawesi Island is the primary controlling factor for the development of sinistral strike-slip. The uplift of the crustal weak area below the Una-Una Volcanic Island was caused by the southward subduction of the North Sulawesi Trench and the northward push of the Banggai-Sula microblock, ultimately leading to the formation of the Una-Una Volcanic Island in Tomini Bay.

Relative risk of the COVID-19 pandemic and regional inflation convergence in Indonesia

This study investigates the relationship between the risk of a COVID-19 pandemic and the regional inflation convergence in Indonesia. It is important to examine the regional inflation convergences to evaluate the inflation rate and the impact of macroeconomic policy on inflation convergence, as the COVID-19 recession differs from the previous inflation recession. To calculate the impact of the relative risk of the COVID-19 pandemic on regional inflation convergence in Indonesia, the dynamic econometric spatial panel data model is used to calculate relative risk without spatial or SIRs. On the contrary, for calculating the risk relative to spatial elements, the CAR Leroux or BSCL Bayesian Spatial Model is used. Using BSCL, the calculation of the relative risk value for the COVID-19 pandemic concludes that Sumatera Island, Java Island, Kalimantan Island, Sulawesi Island, Maluku Island, and Papua Island have high risks, while Bali Island and Nusa Tenggara Island have low risks. In both static and dynamic models, the influence of currency circulation on inflation convergence is positive, and the relative risk of a COVID-19 pandemic on inflation convergence is negative. Studies show that the COVID-19 pandemic is a deterrent to inflation convergence, while the circulation of money drives inflation convergence.

Estimating the Quality of the Most Popular Machine Learning Algorithms for Landslide Susceptibility Mapping in 2018 Mw 7.5 Palu Earthquake

The Mw 7.5 Palu earthquake that occurred on 28 September 2018 (UTC 10:02) on Sulawesi Island, Indonesia, triggered approximately 15,600 landslides, causing about 4000 fatalities and widespread destruction. The primary objective of this study is to perform landslide susceptibility mapping (LSM) associated with this event and assess the performance of the most widely used machine learning algorithms of logistic regression (LR) and random forest (RF). Eight controlling factors were considered, including elevation, hillslope gradient, aspect, relief, distance to rivers, peak ground velocity (PGV), peak ground acceleration (PGA), and lithology. To evaluate model uncertainty, training samples were randomly selected and used to establish the models 20 times, resulting in 20 susceptibility maps for different models. The quality of the landslide susceptibility maps was evaluated using several metrics, including the mean landslide susceptibility index (LSI), modelling uncertainty, and predictive accuracy. The results demonstrate that both models effectively capture the actual distribution of landslides, with areas exhibiting high LSI predominantly concentrated on both sides of the seismogenic fault. The RF model exhibits less sensitivity to changes in training samples, whereas the LR model displays significant variation in LSI with sample changes. Overall, both models demonstrate satisfactory performance; however, the RF model exhibits superior predictive capability compared to the LR model.

Pengelompokkan kabupaten/kota di Pulau Sulawesi berdasarkan indikator indeks khusus penanganan stunting menggunakan Gaussian mixture model

Stunting or is a condition of growth failure in children under five years old (toddlers) who are malnourished. Children are called stunted if their height is below minus two standard deviations. The Special Index for Handling Stunting (IKPS) is one of the main indicators used as a measure of the achievement of handling the reduction in stunting rates. In implementing the 2024 development goals, namely setting a national stunting target that can decrease to 14%, it is necessary to identify based on the characteristics of a special index for handling stunting in each region. Method of Gaussian Mixture Model is a grouping with models that function to group a certain amount of data into a Gaussian distribution with mean and variance parameters. The main idea of model-based grouping is that object grouping is done using probabilities. This study was conducted with the aim of obtaining the results of grouping regencies/cities on Sulawesi Island based on the Special Index Indicator for Handling Stunting. The results of the study obtained different volume and shape models, coordinate axis orientation (VVI) with 4 optimum cluster. Cluster 1 with a low stunting handling index contains 24 districts/cities, cluster 2 with a medium stunting handling index contains 21 districts/cities, cluster 3 with a high stunting handling index contains 13 districts/cities, cluster 4 with a very high stunting handling index contains 23 districts/cities.Keywords: Four optimum cluster, low, medium, high and very highMSC2020: 62A09