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Groundwater quality in Ponjong Karst, Gunungkidul Regency, Special Region of Yogyakarta Avellyn Shintya Sari; Sari Bahagiarti K; Suharsono Suharsono; C Prasetyadi
Journal of Earth and Marine Technology (JEMT) Vol 1, No 1 (2020)
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.2020.v1i1.1142

Abstract

The hydrogeological condition of a region is determined by the type of lithology, morphology, and subsurface conditions where the condition is very helpful in the study of groundwater exploration. Especially when we encounter interesting geological conditions when the groundwater exploration in the karst area in which volcanic rocks are resulting from the activities of the active volcano in the past. Groundwater exploration at Ponjong area and surrounding does have its special characteristics, because it has 2 different rock characteristics where the northern part of the research area in the form of a karst area (limestone of Wonosari Formation) while the southern part is an area of ancient volcanoes with dominant volcanic rocks from Wuni Formation, As for the research on the above and subsurface research area where the research is conducted based on surface geology mapping, geoelectric data collection, and groundwater sampling. Geological mapping includes geomorphological data, stratigraphy, and geological structure. The aquifer system of the research area can be divided into two systems, inter-grain aquifer systems, and fracture aquifer systems. Overall quality groundwater in the research area is quite good. Ponjong District there are mining activities that have resulted in changes in the land use system in the area. This can cause changes in the water surplus in the area due to the changing catchment area.
Reanalysis LUSI Stratigraphic Based on Cutting of Banjarpanji#1 Well Handoko Teguh Wibowo; Bambang Prastistho; C Prasetyadi; Dwi Fitri Yudiantoro
Journal of Earth and Marine Technology (JEMT) Vol 3, No 1 (2022)
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.2022.v3i1.3602

Abstract

The subsurface configuration or stratigraphy of the Sidoarjo Hot Mudflow (Lumpur Sidoarjo/LUSI) is used to see what formations are transported out and how the material properties can be known from the well log data of Banjarpanji#1 or BJP#1 well. There is something unusual about the BJP#1 log, namely the presence of solid volcanic sandstone at a depth of 6000-9297 ft where drilling ended. This abnormality was investigated by reanalyzing volcanic sandstone by reading the well log data which is drilling data during the exploration of the Banjarpanji-1 well by PT. Lapindo Brantas, Inc. which consists of rock logs as a result of predictions (prognosis) and facts found (actual) were then compared with the interpretation of the results of the investigation team with BP MIGAS 2006 which was then confirmed by petrographic and paleontological analysis. The unusual occurrence is the LUSI stratigraphic arrangement changes based on findings in volcanic sandstone sequences that were once considered part of the Kalibeng Formation of Plio-Pliestocene age, then changed to solid volcanic sandstone units of Middle Miocene age with a depositional environment in the outer neritic-upper bathyal.