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Remote Sensing Techniques for Identifying Flood Prone Areas Using the Vegetation Index, Water Index, and Simple Additive Weighting Methods for Mekarsari Areas, Cianjur Regency, West Java Harnani, Harnani; Savira, Putri
Journal of Earth and Marine Technology (JEMT) Vol 4, No 1 (2023)
Publisher : Lembaga Penelititan dan Pengabdian kepada Masyarakat - Institut Teknologi Adhi Tama Suraba

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31284/j.jemt.2023.v4i1.4564

Abstract

Flood is a natural disaster with an intensity that often occurs in cities on a scale with excess water discharge in some areas. This research was conducted to determine the risk of flooding in Mekarsari Village and its surroundings, Cianjur Regency, West Java. (According to InaRisk, 2022) Risk and danger of flooding Moderate – High. This study uses data for the entire year 2022. With several parameters used in this study including land cover, rainfall, soil type, slope, NDVI, NDWI and SAVI. Simple Additive Weighting or weighting for each parameter with different results, according to the classification of each of these parameters. The results of this weighting will become a Flood Hazard Risk Map which was previously the result of overlay and intersection of land cover map, rainfall map, soil type map, slope map, Normalized Difference Vegetation Index map, Normalized Difference Water Index map and Soil Adjusted Vegetation Index map. On the Flood Disaster Risk Map there are five categories of vulnerability levels Not Hazardous, Less Hazardous, Moderate, Hazardous and Very Hazardous. The cause of the risk of flooding in the study area is that most of the land use is diverted to rice fields, plantations, dry agricultural land and settlements so that the lack of vacant land causes low absorption of rainwater and also steep slopes and high elevations which also cause rainwater to be stored in the lowlands. settlements) with moderate to high rainfall intensity every month. There is also a lack of education for the community to mitigate the risk of flood disasters so that waste management and waterways in settlements are inadequate and well managed.
Geotourism Assessment using the M-GAM method (Modified Geosite Assessment Model) Sawahlunto Region, West Sumatra Dezilia, Dieny; Harnani, Harnani
Journal of Earth and Marine Technology (JEMT) Vol 4, No 1 (2023)
Publisher : Lembaga Penelititan dan Pengabdian kepada Masyarakat - Institut Teknologi Adhi Tama Suraba

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.31284/j.jemt.2023.v4i1.4881

Abstract

The geological setting in the area is a strong attraction for natural tourism. The Sawahlunto Geopark area is one of the Geoparks located in West Sumatra Province which has a variety of geological sites. This area meets the criteria that make it a potential Geopark. The purpose of this analysis is to evaluate the potential of geotourism and use this assessment as a basis for developing geotourism in the Sawahlunto and surrounding geotourism areas. This analytical study was carried out using the M-GAM (Modified Geosite Assessment Model) method. In the study process, research methods were carried out using questionnaire data based on 27 indicators from the M-GAM method.M-GAM method has 27 indicators consisting of main and additional values that will be used as a questionnaire which will produce quantitative results. The 27 indicators contain several geotourism assessments, including scientific value, aesthetic value, protection value, functional value, and tourism value of a geosite. The maximum score that can be obtained by a geosite that has all the perfect criteria in 27 indicators will get a main score of 12 and an additional score of 15. 7 geosites will be assessed with results, namely Batu Runciang (8.17 and 7.62), Serpih Bakelok (6.35 and 7.72), Tabiang Tinggi (6.81 and 8.14) and Puncak Cemara (8.19 and 8.41), Stone Garden (6.37 and 7.96), Batu Gantuang Cave (3.91 and 6.07) and Kubang Waterfall (3.48 and 6.48). Referring to the results of the Sawahlunto geosite assessment, it was concluded that the Batu Runciang and Puncak Cemara Geosites had a high value in terms of main values compared to the other 5 geosites. Meanwhile, for additional value, Tabiang Tinggi and Puncak Cemara have sufficient value compared to the other 5 Geosites. This is because geosites with low value still lack various things such as facilities and promotions. Efforts that can be made are to build facilities at several geosites that still experience a lack of public facilities. Apart from that, promotion on social media is also very helpful in introducing geosites to the public.
ASAL USUL FLUIDA MANIFESTASI PANAS BUMI DAN ESTIMASI TEMPERATUR RESERVOIR DENGAN PENDEKATAN ANALISIS ISOTOP PADA DAERAH DANAU RANAU, OGAN KOMERING ULU (OKU) SELATAN, SUMATERA SELATAN: ORIGIN OF GEOTHERMAL MANIFESTATION FLUID AND DETERMINATION OF RESERVOIR TEMPERATURE USING ISOTOPE ANALYSIS APPROACH IN THE LAKE RANAU AREA, SOUTH OGAN KOMERING ULU (OKU), SOUTH SUMATERA Ibrahim, Mochamad Malik; Harnani, Harnani; Jati, Stevanus Nalendra; Abiyyu, Rayhan Khairunnan
Buletin Sumber Daya Geologi Vol 19 No 3 (2024): Buletin Sumber Daya Geologi
Publisher : Pusat Sumber Daya Mineral Batubara dan Panas Bumi

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.47599/bsdg.v19i3.467

Abstract

The geothermal potential of the Lake Ranau area comes from the remains of magmatic activity from Mount Seminung. The geothermal manifestation in this area is in the form of hot springs which are thought to arise through geological structures. The existence of geothermal fluid manifestations is very interesting to research, especially regarding the origin and estimation of reservoir temperature using the δ18O and δ2H isotope composition approach. It is important to know the origin of fluid manifestations to determine the potential of geothermal systems from surface manifestations fluid related to magmatic, evaporation or rock interactions. This research method uses isotope analysis to determine the origin of geothermal fluid manifestations and isotope geothermometer to estimate reservoir temperature. Isotope sampling in geothermal manifestation fluids in Kota Batu Village was 3 samples and Lombok Village was 3 samples. The results of isotope analysis on the relationship graph between δ18O and δ2H show that all isotope samples in geothermal manifestation fluids come from meteoric water. The local meteoric water line value equation has a difference in the deuterium excess (DE) value compared to the global meteoric water line value equation. This change in DE value is due to the interaction and mixing process between geothermal fluid and rock (connate water) with the source of evaporation and precipitation from Lake Ranau. The results of isotope geothermometer calculations based on the isotope fractionation factor, it is estimated that the reservoir temperature is around ± 270 0C. Reservoir temperature estimates show that all isotope samples in geothermal manifestation fluids are classified as high temperatures.
WATER BALANCE CHARACTERISTICS OF KEI KECIL ISLAND, SOUTHEAST MALUKU: AN INITIAL APPROACH TO GROUNDWATER MANAGEMENT ON A SMALL CARBONATE ISLAND Nurohim, Dede; Setiawan, Budhi; Harnani, Harnani; Febrim, Dwi Vina
Journal of Geological Sciences and Applied Geology Vol 9, No 3 (2026): Journal of Geological Sciences and Applied Geology
Publisher : Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24198/gsag.v9i3.72466

Abstract

Small carbonate islands commonly depend on groundwater as their primary freshwater resource, making an understanding of water availability essential for sustainable groundwater management. This study characterises the water balance of Kei Kecil Island, Southeast Maluku, Indonesia, as an initial step toward understanding groundwater availability in a small carbonate-island environment. The study used precipitation, evapotranspiration, and available water capacity (AWC) data. Precipitation and evapotranspiration data for 2000–2025 were processed spatially and temporally to derive monthly and annual characteristics within the Kei Kecil Island boundary. AWC data for the upper 0–30 cm soil layer were used to support the interpretation of near-surface water storage. The water balance was determined from the difference between precipitation and evapotranspiration and was subsequently evaluated at monthly and annual scales. The results show a mean annual precipitation of 2,409.94 mm/year and mean annual evapotranspiration of 1,488.95 mm/year, resulting in a positive annual water balance of 920.99 mm/year. The AWC ranged from 4.95 to 63.75 mm, with a mean of 35.60 mm, indicating spatial variation in the upper soil layer's capacity to retain water. The positive water balance shows that precipitation provides an important water input to Kei Kecil Island's hydrological system after accounting for evapotranspiration losses. However, the calculated water surplus cannot be directly considered equivalent to groundwater recharge because excess water may be partitioned into infiltration, runoff, soil-water storage, and groundwater discharge. The findings provide a preliminary hydrological framework that complements existing information on the freshwater groundwater system and supports using water balance characterisation as an initial approach to groundwater management on small carbonate islands.