Kajian daya dukung geologi rencana lokasi Tempat Pembuangan Akhir di Desa Botok, Magetan, Jawa Timur

Abstrak.Tempat Pembuangan Akhir (TPA) sampah Milangasri di Kabupaten Magetan telah mencapai daya tampung maksimum. Pemerintah Kabupaten Magetan berencana membangun TPA baru di Desa Botok. Penelitian ini bertujuan untuk melakukan kajian kelayakan daya dukung geologi rencana lokasi TPA baru. Kriteria daya dukung geologi mengacu pada SNI 03-3241-1994 tentang tata cara pemilihan lokasi TPA. Metode penelitian meliputi investigasi lapangan dan pengumpulan data sekunder. Penelitian lapangan meliputi pengamatan kondisi geologi, pemetaan topografi, survei geolistrik, pemboran inti dan uji permeabilitas lapangan serta pengamatan sumber air terdekat. Data sekunder meliputi informasi yang berkaitan dengan potensi bahaya geologi. Hasil penelitian menunjukkan bahwa kelulusan batuan antara 1,26 × 10-2 hingga 1,59 × 10-2 cm/detik tidak memenuhi kriteria. Sehingga secara alami, lokasi ini kurang layak dijadikan sebagai lokasi TPA. Namun demikian, rekayasa teknologi dengan memberikan lapisan kedap air pada alas TPA seperti compacted clay liner atau geosynthetic liner menjadikan area ini layak untuk TPA. Abstract.Current landfill in Milangasri nearly reach its maximum capacity. The government of Magetan regency plans to build a new landfill in Botok. This research aims to assess the land capability based on geological characteristics of the landfill location. The SNI 03-3241-1994 used as basic criteria for selecting landfill area. Research methods consist of field investigation supported by secondary data. Field investigation consist of geological observation, topography mapping, resistivity survey, core drilling and field permeability testing, and water source observation. Information of potential geological hazard collected as secondary data. The results show that the hydraulic conductivity of the quaternary deposit ranging of 1.26 × 10-2 to 1.59 × 10-2 cm/s, failed to meet the criteria. Therefore, by nature the location candidate not supported geologically as landfill location. However, application of compacted clay liner or geosynthetic liner as the base of the landfill is recommended to improve the capability.

Mineralogical studies of amphibolite outcrops within the Kryvyi Rih Basin

This study explores the mineralogical composition of the material of samples extracted from the outcrops of amphibolites located within the Kryvyi Rih Basin. Amphibolites of the Novokryvorizka suite of the Kryvorizka series are located in the area of Rodina mine of the Kryvyi Rih Iron Ore Enterprise (KRIOE) on the right bank of the Saksahan river, where the amphibolites crop out as an interrupted line. Over the recent years, industrial and geological tourism has been actively developing not only within Kryvyi Rih, but also in Ukraine in general. The Kryvyi Rih Basin has many objects which deserve the status of unique geological observation sites. One such site has amphibolites of the Novokryvorizka series, which rarely outcrop to the surface. Such an object is interesting and useful not only for interested tourists, but especially for geology students as an example of rocks that have been formed out of effusive eruption products during the geological process such as regional metamorphism. No other examples of their exposure have been observed in the area. The studied outcrops are unique, but recently, their reduction has been observed due to the poor level of their preservation. The relevance of this study is conditioned by necessity of conducting geological evaluation of the amphibolite outcrops with a view to the future use of this object for development of industrial and geological tourism within the Kryvyi Rih Basin. We studied all possible outcrops of the amphibolites within the surveyed territory, and analyzed the results of the previous studies on the topic. We developed a schematic image of the outcrops with consideration of their thicknesses. The mineralogical composition of all outcrops of the amphibolites was studied for further determination of the exact age of the amphibolites and opportunity of providing the amphibolite outcrops with the status of unique observation sites. For achieving the goal, we used the following methods of study: geological survey, selection of representative petrographic samples of the amphibolites, mineralogical and petrographic analyses, generalization of results of field and laboratory studies.

The Geology of the Perches - Terrier Rouge Area, A Potential Copper and Gold Mineralized Belt in Northern Haïti.

A geological reconnaissance at an approximated scale of 1:100000 was done over 112 km2, between the townships of Roche Platte to the West, Jasquezyl to the North, Grand Basin to the East, and Perches to the South. A total of 56 points were described for an average of one geological observation per two square kilometers.Also, 18 grab samples were taken from mineralized showings, as well as three heavy mineral concentrates and two samples for whole rock analysis.All the collected information was kept in a database created on MS Access by the author of this report. The database, including the results of the analysis, can be consulted on Mendeley at doi:10.17632/b35fmjntnr.1.A model for the regional geological evolution of the area is presented, as well as a proposal for the denomination of the three basic geological structures found in the area, The Douvray Volcanic Group, the Grand Basin Magmatic Complex, and the Bercera Volcanic Formation, which the author interpreted as the last volcanic event of the Douvray Volcanic Group.This study revealed several new prospective zones for copper to the North, and gold-copper-lead-zinc mineralization to the South, along the volcanic belt and its orogenic intrusives, chiefly related to the occurrences of iron hats.The author recommends more detailed prospecting work, including ground geophysics and trenching, to better evaluate the ore potential of these new areas.

Rainfall Thresholds for Landslide Prediction in Loano Subdistrict, Purworejo District Central Java Province

Purworejo Districtis a district with high disaster risk index in Indonesia, especiallylandslide. The main factor that triggers the landslide is rainfall. However, therehas been no comprehensive research on the intensity of rain that triggered the landslide in Purworejo District, especially in the Sub district of Loano. Huge landslide occurred in Loano Sub district at 2016, causing 46 deaths and damages in several houses. Therefore, it is necessary to study the prediction of landslide based on rainfall data and geological conditions of Loano Sub district, Purworejo District. The objective of this research is to analyze the mechanism of landslide, to analyze the rainfall that triggers the landslide and to estimate the intensity of rain that can triggers the landslide. The research method is collecting historical data of landslides in Purworejo District along with rainfall data, geological observation that includes the condition of lithology, geomorphology and hydrogeology,undisturbed soil sampling in Loano Sub district. The prediction of landslide uses empirical methods which were then simulated by Geostudio 2012 Software. The results show that the type of landslide is sliding, the main control factor is the steep slope and the thickness of the soil. The rainfall threshold triggering landslide are as follows for lithology andesite breccia I = 81.782 D􀀀1.197, sandy clay I = 92.579 D􀀀0.13, and andesite intrusionI = 145.32 D􀀀0.338.

Coastal Characteristic and Abrasion Hazard in Putri Island, Nongsa, Batam

Putri Island, Nongsa is the outer and frontier island of NKRI region bordering Singapore. Its existence is very important both economically and politically. The management of Putri Island should consider the coastal characteristic that describes character and physical of the beach as the result of interaction between marine influence and coastal condition, geophysical and anthropogenic elements. The purposes of the study are mapping the coastal characteristics as an effort to manage frontier island and describing the abrasion hazard that occurred in this area. The study area is Putri Island, Nongsa. Field survey was conducted in May 2014. Coastal characteristic method wes conducted through geological observation, coastal morphology and coastline character. Bathymetry measurement conducted by echosounder, tidal observation by peilschaal and wind observation by a weather station. The study results show the type of tide is mixed predominantly semi diurnal. The dominant current direction is to the northeastern. The bathymetry conditions between Putri and Batam Island have a depth of up to 20 with a slope of 2.50 and towards the Singapore Strait has a depth of up to 70 m with a slope of > 100. Coastal characteristics of Putri Island is divided into 5 types, ie sandy beaches, mangroves, coral, rocky and cliff. Generally, sandy beaches, mangroves, rocky, rocky have flat morphology and consist of sand, mangroves, coral reefs, gravel and boulder. Low-cliff beaches consist of conglomerates of various materials that are not well consolidated. The abrasion hazard threatens the Putri Island, Nongsa, especially in the north-western part of the island. The abrasion of Putri Island should be managed and performed based on the coastal characteristics of the area.