Sequence stratigraphy involves studying a series of rock layers deposited during a full change cycle in accommodation or sediment supply, bounded by subaerial unconformities and marine correlative conformities. This study aims to identify the stratigraphic sequence that controls the coal accumulation models and their influence on the coal geometry. The research methodology includes geological mapping, analysis of geophysical logs (gamma-ray and short density), and core log analysis. The data were analyzed, combined, interpreted, and simulated to create a model of coal accumulation and geometry. The M2 Member of the Muara Enim Formation comprises six lithofacies, as determined by analyzing four drill holes. The M2 Member of the Muara Enim Formation exhibits four depositional environments (crevasse splay, mire/swamp, mudflat, lagoon, and tidal/mouth/distal bar) and three facies associated with the fluvial delta–tidal plain facies (fluvial dominated upper delta plain, tide-dominated lower delta plain, and marginal tidal plain and lagoon). This research identified four system tracts, namely TST-1, HST-1, TST-2, and HST-2. TST-1 and TST-2 show continuous coal deposition, inclined to steeply inclined, interspersed, and characterized by the presence of three layers of clay bands. Similarly, HST-1 and HST-2 exhibit continuous coal deposition with gentle to steep inclined and interspersed, ranging from moderately thick to very thick, and containing one to five layers of clay bands. The tectonic activity after deposition caused the deposited coal to deform. The findings of this study contributed to guiding the exploration of coal seams in the South Sumatra Basin and Muara Enim Formation, in particular.

This study investigates the influence of bedrock on nickel (Ni) content in laterite deposits in the Lameruru Region, Langgikima District, North Konawe Regency, Southeast Sulawesi Province, Indonesia. The research area is dominated by ultramafic rocks, which are potential sources of laterite nickel. The study employs literature review, field surveys for lithological data collection and representative sampling, petrographic analysis to determine mineral composition and rock types, and geochemical analysis using X-Ray Fluorescence (XRF) to determine nickel content in the rocks. The results show that the bedrock in the study area consists of harzburgite and olivine pyroxenite. Harzburgite, occupying approximately 72.72% of the area, is composed of 54-78% olivine, 15-45% orthopyroxene, 6% clinopyroxene, and accessory minerals, while olivine pyroxenite, occupying about 27.28% of the area, is composed of 27% olivine, 49% orthopyroxene, 17% serpentine, and 7% spinel. Geochemical analysis reveals that harzburgite has higher Ni content (0.10-0.16%) compared to olivine pyroxenite (0.03-0.10%). The distribution of Ni in the bedrock and saprolite is directly proportional, with higher Ni content in harzburgite in both zones. The study concludes that the type of bedrock greatly influences the nickel content in laterite deposits, with harzburgite having a higher Ni content due to its higher percentage of olivine minerals, which are the main hosts of nickel in ultramafic rocks.

The increasing frequency and intensity of flooding in Kesambi District, Cirebon City, has caused significant economic losses and disrupted people's lives. This study attempts to manage flood disaster risks through careful planning. By combining spatial data analysis and an associative descriptive approach, this study produces a map of evacuation places and routes that can be relied on to deal with future floods. The results of the study indicate that the potential for flooding in Kesambi District causes extensive damage and has a significant impact on people's lives, especially in Drajat, Kesambi, and Pekiringan Sub-districts. Thousands of residents of Kesambi District are exposed to disaster risks and damage to buildings and infrastructure that hinder mobility and economic activity. Based on the analysis of capacity, travel time, and distance, this study has determined 6 evacuation places that can accommodate the estimated number of evacuees and 40 existing evacuation routes can be safely passed. These six evacuation places are considered strategic because they are close and can be reached in a short time, making it easier for people to immediately carry out independent evacuation when a disaster occurs.

Sorowako and surrounding areas are geologically influenced by Sulawesi’s microcontinent movement, which has produced several geological phenomena. Morphometry is one of the parameter that can reveal geological condition of particular area. Morphometric analysis of water catchment area in Sorowako and surrounding areas using Bifurcation Ratio (Rb) and Drainage Density (Dd) can provide comprehensive information on level of deformation in Sorowako region. Analysis result of Bifurcation Ratio Index (Rb) on water catchment area reveals that Rb<3 value is dominant and equally spread in Sorowako region, it varies from 0.094 to 2.888. However in several place the value of Bifurcation Ratio (Rb) index is more than 5 (Rb>5) with varies from 5.142 to 10.250. Drainage Density (Dd) value ranges from 0.907 to 8.422 with an average value is 4.125 describes impact of erosion and tectonic on Sorowako region. Based on morphometric analysis of two parameters, Sorowako and surroundings area have been heavily impacted by tectonic activity on Sulawesi island. In western, eastern and northern regions on water catchment area, level of deformation tends to be higher compared to southern region. This can be seen on analysis result of water catchment area 43, water catchment area 196, and water catchment area 302 that have relatively larger number of stream orders, and also have Bifurcation Ratio’s value less than three (Rb<3). Information of tectonic deformation level on Sorowako region through morphometric analysis is important to further use as a basis for water catchment area management planning, so that it can identify areas prone to geological disasters. This fairly high level of tectonic deformation also believed to be a controlling factor for nickel grade contained in Sorowako and surrounding areas which allow supergene enrichment to occurs in rocks.

Climate change has prompted significant global interest in carbon sequestration technologies, particularly using geological formations. This study investigates the potential of ultramafic rocks from the Kolaka Ophiolite Complex in Southeast Sulawesi for carbon sequestration, focusing on the mineralogical, petrographic, and geochemical characteristics that enhance their reactivity with CO₂. The research involved petrographic and mineragraphic analyses of 15 peridotite samples, geochemical measurements via X-ray fluorescence (XRF), and mineral characterization using scanning electron microscopy (SEM). The results revealed that Kolaka's ultramafic rocks, particularly harzburgite and lherzolite, exhibit moderate to high serpentinization, which enhances their reactivity with CO₂. Key minerals such as olivine, pyroxene, and serpentine, rich in magnesium, calcium, and iron oxides, demonstrate significant potential for mineral carbonation. Secondary minerals like magnesite and brucite were identified as products of carbonation, reinforcing the rocks' ability to act as carbon sinks. The discussion highlights that serpentinized peridotites are more effective for carbon sequestration than unaltered ones due to increased mineral reactivity. The presence of magnesite and Cr-Fe-rich carbonates, alongside serpentine veins, indicates that fluid-rock interactions have promoted ongoing carbonation processes. The Kolaka ultramafic rocks, therefore, hold strong potential for long-term carbon storage, offering a promising solution for reducing atmospheric CO₂ levels

Digital Elevation Model (DEM) is well known for providing solutions to the theoretical and application-related problems around geosciences. The use of DEM in flume tank experiment is getting more common nowadays. Flume tank itself is built to simulate the landscape and stratigraphy at laboratory scale. This physical experiment may have tremendous impacts on understanding the sedimentation process in a laboratory-scaled experiment. Normally, the morphodynamic behaviour of a laboratory-scaled deposit in the flume tank experiment would be observed through its digital elevation model. In this paper, a novel method in constructing cost-efficient digital elevation model was presented. By using this inexpensive tool to create a digital elevation model in a flume tank experiment setup, some challenges and benefits will follow this method. Some challenges including tool’s resolution and time consuming could be diminished in the near future by creating automated motor system to move the laser distance meter sequentially. Automated and integrated system from the LDM to the processing software could also reduce the time consumption. In the other hand, some benefits including financial benefit, reliability in a sedimentary structure scale, and also the practicality to be applied in any flume tank system available in Indonesia. Nevertheless, this method had been tested and some reliable results from the previous studies in Quantitative Sedimentology Laboratory, Universitas Indonesia was presented in this paper. Hopefully, some major improvements could be done to get more accurate and detail digital elevation model in the near future.

Nowadays, the development of infrastructure has caused an increase in the need for cement. To determine the suitability of the raw materials used in cement production, an assessment must be carried out on the quality anMineralogical and Geochemical Clay Analysis for Portland Cement Quality Distribution: A Study Case From Ajibarang District, Central Java, Indonesiad suitability of the cement raw materials. This research was conducted in Halang Formation of the Tipar Kidul area and around Banyumas Regency, Central Java. The methods used are X-ray fluorescence (XRF) and scanning electron microscopy (SEM). Data from XRF analysis generally shows SiO2 values from 26.83% to 57.75%, Al2O3 values from 11.18% to 20.23%, and Fe2O3 values from 3.21% to 8.76%. Judging from the aluminum index (AI) content, the ideal cement raw materials are two samples with a proportion of 3.17% to 3.22%. The results of SEM analysis show that there are illite, calcite, quartz and smectite minerals in the claystone research area. Based on data, almost 75% of the claystone survey area was found to be suitable as a raw material for cement. This research has a positive impact on the characterization of limestone as a raw material for cement by utilizing geochemical analysis and electron microscopy to achieve a more comprehensive understanding of the evaluation of limestone quality.

The Boreal Summer Intraseasonal Oscillation (BSISO) is intraseasonal climate variability in addition to the Madden-Julian Oscillation (MJO) that affects weather and climate in the Indo-Pacific region including the Province of Aceh. The impact of BSISO on extreme rainfall and flooding in Aceh needs to be investigated to enhance preparedness, mitigation, and adaptation strategies against its negative impacts. The datasets use in situ daily rainfall data from 5 BMKG stations in Aceh and the BSISO indices (BSISO1 and BSISO2) during the extended boreal summer (May–October) period 2001–2020, as well as flood event data in Aceh from 2008–2020. The results of this study show that rainfall in Aceh province is influenced by BSISO variability and has the potential to increase extreme rainfall and even cause flooding in some areas in Aceh, depending on the propagation path of BSISO. The frequency of extreme rainfall in Aceh during BSISO is identified using daily rainfall beyond the 95th percentile in each BSISO phase, which increases the probability of extreme rainfall in Aceh by around 20–100% during phases 1-3 in both BSISO1 and BSISO2. During BSISO1, the probability of flooding in phases 1-3 increased by up to 90%, and BSISO2 also increased the probability of flooding in phases 1-4 by up to 72%.

The main task of PDAM Tirta Intan Garut Regency is to manage raw water into clean water for customers. The management of raw water supply in Bayongbong District for the community still relies on springs with a gravity system, deep well pumps and rivers. The flow of the Cimanuk River in Bayongbong District can be used to provide raw water. Four rainfall stations are used. Average rainfall is calculated using the Thiessen method. The raw water collection point does not have a automatic water level recorder (AWLR), so it is necessary to create a model to obtain the discharge at the collection point. The model used is the water balance model from F.J. Mock. Calibration of model parameters was carried out on observed discharge at Cimanuk-Bayongbong AWLR and Cimanuk-Bojongloa AWLR. To test the reliability of the model, NSE and RMSE values ​​were used. The NSE and RMSE values ​​in the Cimanuk-Bayongbong catchment area are 0.515 and 3.615 and Cimanuk-Bojongloa are 0.593 and 4.813. The results of the model parameter calibration are used to calculate the discharge at the collection point. The calibration result ​​at the collection site are exposed surface 50%, infiltration coefficient 0.5: recession coefficient 0.35: catchment area characteristic factor 10%; and soil moisture capacity 200 mm. The dependable flow is calculated based on Q90% probability, water availability in July, August, September and October is 0.078 m3/s; 0.025 m3/s; 0.035 m3/s; and 0.025 m3/s. Water availability in that month is smaller than the discharge requirement for the next five and ten years, namely ranging from 0.134 m3/s to 0.168 m3/s and 0.145 m3/s to 0,182 m3/s.

Land subsidence is a naturally occurring phenomenon that has become a growing concern in various regions, including Lampung Province. In this study, we investigate land subsidence in various cities within Lampung Province, Indonesia, utilizing Sentinel-1A using Sentinel-1A satellite image data from the period 2014 to 2022. The cities of Lampung Province analyzed in this study were Liwa, Kota Agung, Kalianda, Sukadana, Bandar Lampung and Krui. The method used is Interferometric Synthetic Aperture Radar (InSAR) with the Small Baseline Area Subset (SBAS) technique. Furthermore, to validate and improve the accuracy of land subsidence measurements, the Global Navigation Satellite System (GNSS) velocities were utilized. The land subsidence result obtained in this study is presumed land subsidence. The cities that experienced land subsidence was Kalianda, Sukadana, Bandar Lampung and Krui ranging from ~3 mm/yr to ~15 mm/yr. Meanwhile, the areas that experienced an uplift were the Liwa and Kota Agung cities.