Pendekatan Hidrogeomorfologi Dan Pendugaan Geolistrik Untuk Identifikasi Potensi Airtanah Di Jedong Malang

This study aims to identify the potential groundwater in Jedong, Malang, East Java. The hydrogeomorphological approach is a suitable approach to describe the relationship between hydrological and geomorphological processes on and below the earth's surface. The survey of geoelectricity complements the hydrogeomorphological approach. It will give a better description of the groundwater conditions below the earth's surface. Based on the research, there are 2 hydrogeomorphological units in the study area, which are: Volcanic Foot Valley Unit and Volcanic Foot Ridge Unit. The best groundwater potential is in Volcanic Foot Valley Hydrogeomorphological unit, namely Awar-awar Valley and Cokro Valley. The valleys are dominated by gully erosion and landslides. They have surface deposits up to a depth of 7 meters, and lots of outcrops of breccia, pumice, and andesite boulders. The valley’s springs discharge between 56 - 198 m3/day. The average infiltration rate in the valley is 1776 mm / hour, with sandy soil material. The best aquifer consisting of sandy material is more than 10 meters in depth, based on the geoelectrical survey. Water in the aquiclude layer, cannot be exploited because it is breccia and tuff material. The Sawah valley cannot be exploited further because the groundwater potential is very low. This can be identified by the thick water outflow seepage. In the Volcanic Foot Ridge Hydrogeomorphological unit, the groundwater potential is also very small. Hydrogeomorphically, water will flow down the slope to the valley. It will reduce the infiltration rate. In general, the ridge area is only used for settlement, while the slopes are used for dryland agriculture. The geoelectric analysis results show that the groundwater potential is at a depth of more than 45 meters. This research’s results show that the combination of the hydrogeomorphological approach and the geoelectric use will provide a better description of the potential groundwater.

Studi Mekanisme Sedimentasi Formasi Dolokapa, Gorontalo

The Dolokapa Formation is a sedimentary rock formation formed in a deep-sea depositional environment with a fairly complex level of deformation and tectonic arrangement. Analysis of the sedimentation mechanism is carried out to determine how much tectonic influence on the mechanisms that occur in a depositional environment and the variations in the sedimentation mechanism formed. Research on the sedimentation mechanism needs to be carried out to determine the history of the formation of Gorontalo sedimentary rocks, especially in the Dolokapa Formation which was formed during the Miocene. The purpose of this study is to know the mechanisms of deep-marine sedimentation based on the identification of lithological characteristics, layer stacking patterns, and sedimentary structures. The method used was measuring sections using a range of ropes divided into four measurement paths. After that, a correlation was performed based on the genesis of deep marine formation. Based on the results of processing and analysis of the data, obtained units of lithology that insertion silty-clay, and the sandstone graining insertion of silt. In vertical succession, the layering pattern formed generally thickens upwards which describes the energy of the depositional currents. The sedimentary structure consists of rip up-clast, parallel lamination, graded bedding, convolute, slump, and trace fossils of nereites trace fossils of nereites that characterize the sedimentation of traction currents and turbidite currents in the deep-sea environment. The sedimentation mechanism formed is the traction current mechanism which is a further development of turbidite current and high-low concentration turbidity current mechanism that occurs slowly on a suspension-controlled grain. The stratigraphic relationship of the rock units in the research area is aligned based on the genesis formation that is located in the setting of the deep marine.

Heterogeneous Correlation Map Between Estimated ENSO And IOD From ERA5 And Hotspot In Indonesia

El Nino-Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) can reduce the amount of rainfall in Indonesia. The previous study found that ENSO and IOD derived from the OISST dataset have an association with hotspots in Indonesia, especially in southern Sumatra dan Kalimantan. But the correlation results are still too small, and the correlation strength between regions has not been analyzed. Therefore, this study quantifies the association of the estimated ENSO and IOD derived from the ERA5 dataset on hotspots in Indonesia based on a Heterogeneous Correlation Map (HCM) and analyzes the correlation strength between regions in Indonesia. We use a singular value decomposition method to quantify this HCM. Besides OISST, ERA5 is an estimation data often used for weather forecast analysis. Therefore, this study quantifies the association of the estimated ENSO and IOD derived from the ERA5 dataset on hotspots in Indonesia based on a Heterogeneous Correlation Map (HCM) and analyzes the correlation strength between regions in Indonesia. Based on variance explained and correlation strength, the hotspot in Indonesia is more sensitive to ENSO and IOD derived from ERA5 than OISST. Consequently, the ERA5 data more useful to statistical analysis that requiring a substantial correlation.

Analisis Tipe Dan Bidang Gelincir Longsor Di Kabupaten Gorontalo Utara

The purpose of this study was to determine the type of landslides and analyze the landslide slip in North Gorontalo District, Gorontalo Province using the geoelectric method. This research begins by determining the type and kind of landslides found in the North Gorontalo District. The location of the measurement was carried out at 4 (four) locations, 1st Track in Tomilito District; 2nd track in Sumalata District; 3rd track in Monano District; and 4th track in East Sumalata District. The research method used was a field survey with a land unit approach. Data analysis to determine the type and kind of landslides is using the landslide classification index method. Analysis of geoelectric measurement results using the Schlumberger-Configuration. The results showed that the types of landslides that occurred in North Gorontalo Regency were the type of planar slide, rotational slide, slide flow, rock/topples. The average depth of the landslide slip that occurred was 5 – 15.9 meters. In general, landslides that occur in North Gorontalo Regency are caused by high rainfall and land conversion for agriculture.

Tingkat Kerawanan Kebakaran Hutan Dan Lahan Di Banjarbaru Provinsi Kalimantan Selatan

One of the areas in South Kalimantan that is prone to land fires is the Banjarbaru area, especially on peatlands. The fire in Banjarbaru is important because of the vital object of Syamsudin Noor Airport. Mapping of fire vulnerability was important for the Banjarbaru area, which had repeated fires throughout the year. The objective of the study was to analyze the vulnerability of forest and land fires in Banjarbaru, South Kalimantan Province. This study used Landsat 8 Oli Tirs imagery to obtain NDVI data and land cover maps from INA-Geoportal. The analysis of data used the scoring and overlay of the two maps. The level of vulnerability was dominated by the high vulnerability. The high level of vulnerability in Cempaka District was 81.9 %, in Banjarbaru Selatan District was around 99.5 %, in Banjarbaru Utara District was around 95.3 %, in Landasan Ulin District was around 94.1 % and in Lianganggang District was around 88.9 %. Land cover in the form of agriculture, plantations, and shrubs with moderate-high density caused the land to be more prone to fires.

Simulation Of The Volcanic Ash Dispersion During The June 2019 Sinabung Eruption

The eruption of Sinabung on June 9, 2019, was categorized as a red code in the warning report for flights. Volcanic ash from volcanic eruptions is a serious threat in the world of aviation with the most dangerous ash particles are 6-10 μm and 37 μm in diameter. To enrich our understanding and modeling performances of the volcanic ash dispersion for the Sinabung eruption case, it is necessary to simulate the dispersion of volcanic ash in those particular sizes to see its distribution which can impact flight routes. The method used was the analysis of the direction and dispersion of the particular volcanic ash using Weather Research Forecast-Chemistry (WRF-Chem) and compared it with the volcanic ash warning information on flight routes issued by Volcanic Ash Advisory Centers (VAAC)-Darwin. In general, WRF-Chem can simulate the distribution of volcanic ash from the eruption of Sinabung at the two-particle sizes at different heights, and found the difference in the distribution direction of the two groups of the particle sizes. Comparison results with warning information from VAAC-Darwin and previous study, WRF-Chem simulation shows a good concordance in the dispersion direction.

Extentional Fault Pada Daerah Compressive Tectonic Zone Sebagai Batas Cekungan Di Jawa Tengah Selatan

The extensional structure as a normal fault could be found in many places at the southern part of Java compressive tectonic regime. The research area is in the eastern part of the South Serayu Mountains. This normal fault structure is the boundary of the South Serayu Mountains at the eastern part with Kulon Progo Tertiary volcanic Mountains. In the field, these normal fault lineament zones create the Bogowonto river as a boundary of two different geological styles. The influence of this structure on the geological dynamic of the South Serayu Mountains and the Kulon Progo Mountains is important to be explained. The study was conducted by measuring and analyzing fault data and lithology that developed in the area around the two basins boundary. The distribution of the Kulon Progo volcanic rocks indicates the presence of the extensional fault structure. The volcanic facies distribution of the volcano is cut and becomes narrow in the west, while the northward is very wide. Normal fault striations analysis on the fault plane along the fault line shows the least stress trending west-northwest that has worked to create North-South normal faults. The fault-controlled by stress with the vertical main compression area. They have worked to create North Northeast-South Southwest (NNE-SSW) normal faults with westward dipping.

Sebaran Konsentrasi Coliform Dan Escherichia Coli Pada Air Tanah Dangkal Kota Gorontalo

This study aims to analyze the spatial distribution of coliform and E. coli in groundwater Gorontalo City and the factors that influence it. The sampling locations were taken from 9 sub-districts consisting of 27 villages. The nine sub-districts consist of Dumbo Raya, Hulondalangi Kota Barat, Kota Utara, Kota Timur, Kota Selatan, Sipatana, Dungingi, and Padebuolo Districts. Sampling in each village consisted of 1 sample and was taken randomly. Kota Utara Sub-district consisted of 1 sample location, namely Dembe Jaya Village. Kota Timur Sub-district consists of 2 villages, namely Padebuolo and Heledulaan Selatan villages. Kota Selatan sub-district consists of Limba U 1. Kota Tengah sub-district consists of Liluwo Village. The Sipatana sub-district consists of Tanggikiki, Bulotadaa, and Tapa Villages. Dungingi sub-district consists of Tulandenggi and Libuo Villages. The total number of samples was 27. The analysis was carried out at the Gorontalo District Health Office, UPTD of Water Quality Laboratory Installation. The sampling method was carried out aseptically. Measurements in the laboratory used the MPN method. The quality standard that became the reference was Permenkes (Health Minister Regulation) number 32 of 2017 Annex 1 regarding water for sanitation and hygiene. The results of the analysis showed that the distribution of the number of coliform bacteria, in general, was at the quality standard set. A total of 24 villages of 27 locations were above the established quality standard. Regarding the number of E. coli bacteria from 27 locations, there were 5 locations above the established quality standards. The factor that affected the pollution was the distance of the septic tank which was very close to the well (water source).

Koreksi Bias Statistik Pada Data Prediksi Suhu Permukaan Air Laut Di Wilayah Indian Ocean Dipole Barat Dan Timur

The IOD can be measured using the Dipole Mode Index (DMI) which is calculated based on the sea surface temperature in the Indian Ocean. Therefore, DMI can be predicted using sea surface temperature forecasting data, such as data provided by the European Center for Medium-Range Weather Forecasts (ECMWF). However, the data still has a bias as compared to the actual data, so to get a more accurate prediction, corrected data is needed. Therefore, the aim of this study is to predict DMI based on sea surface temperature forecasting data that has been corrected for bias using the quantile mapping method, a method that connects the distribution of forecasting and actual data. The results showed that the DMI prediction using corrected data was more accurate than the DMI prediction using ECMWF data. DMI predictions using corrected data have high accuracy to predict IOD events in October-April.

Analisis Parameter Gempabumi Dengan Struktur Geologi Di Daerah Asparaga, Gorontalo

Gorontalo is an area located in the North Arm of Sulawesi which has a complex geological structure as a result of the submergence of the Sulawesi Sea and East Sangihe so that this area is considered an earthquake-prone area. The existence of the regional structure and the mapping of the earthquake point distribution is interesting to be studied more deeply because it affects seismic activity in the area. The purpose of this study is to analyze earthquakes in the Asparaga area based on their depth and magnitude and to relate them to the geological structures found in the study area. The earthquake data used were obtained from USGS. Satellite image data used is the SRTM satellite image. Earthquake data is mapped to produce depth maps, magnitude maps, and earthquake zoning maps. Lineament data were processed using a rosette diagram. Lineament can reflect the morphology observed on the earth's surface as a result of the activity of geological forces. The results showed that the Asparaga area had shallow earthquake depths and moderate to large magnitudes. The focus of the earthquake was right on the path traversed by the geological structure and its relatively northwest-southeast direction. The geological structure in the research location is the epicenter of the earthquake because it is crossed by regional geological structures.