Groundwater Chemistry Characterization in the South and Southeast Merapi Volcano, Indonesia

Abstract

Merapi Volcano, which differs from volcanoes in other climates due to its location on the Indonesian Maritime Continent influenced by ENSO, ICTZ, and Moonsons, plays an essential role as a source of groundwater for the surrounding population. Some problems associated with groundwater in Mount Merapi are high utilization compared to other volcanoes worldwide, changes in land use, pollution, and its lowering table. Therefore, this study aims to compare the hydrogeological characteristics and aquifer systems of the southern and southeastern parts of Merapi Volcano. The hydrogeological characteristics were obtained from geological mapping, surface and subsurface, as well as rock XRF tests. Meanwhile, the hydrogeochemical characterization was determined through chemical data using the Trilinear Piper, Kurlov, Fingerprint, Composition, and Harker Diagram methods. The results of the Trilinear Piper, Kurlov, Fingerprint, and Composition Diagram methods show that Mount Merapi has 3, 7, 4, and 2 types of patterns different from other volcanoes in the world. On the other hand, the Harker diagram has the same pattern of Mg-Ca and Mg-Na as several other volcanoes. In conclusion, the hydrostratigraphy in the southern part of the volcano, consists of aquifuge, aquiclude, and aquifer, while in the southeast, there are aquitards of volcanic sandstone and tuff.

Karakteristik Hidrogeologi dan Hidrogeokimia DAS Tempuran Lereng Barat Kompleks Gunungapi Bromo-Tengger

“…Pola sebaran suhu rendah pada bagian hulu dan semakin meningkat dari tengah hingga ke hilir (Gambar 6b). Pola nilai DHL, pH, TDS, dan suhu semakin naik dari hulu ke hilir Gunungapi sesuai dengan penelitian Hendrayana et al, (2023).…”

“…Pola sebaran kalsium nitrat bikarbonat berada pada bagian hulu kemudian berubah komposisi menjadi kalsium bikarbonat pada bagian tengah (Gambar 7a). Hasil tersebut sesuai dengan penelitian Hendrayana et al, (2023) (2009). Sifat kimia air ion kalsium dan magnesium (alkali tanah) lebih tinggi dibanding ion sodium + potassium (alkali) dan ion bikarbonat yang lebih tinggi dibanding ion klorida dan sulfat.…”

“…Sampel air tanah yang termasuk ke dalam sistem 3 adalah SG 9. Pola sistem 1 dan 2 memiliki kesamaan pada hasil diagram fingerprint pada Gunungapi lainnya (Hadian et al, 2016;Hendrayana et al, 2023;. 5.…”

“…Pada bagian lereng lainnya belum pernah dilakukan kajian kimia air tanah, potensi air tanah, dan imbuhan air tanah. Terdapat perbedaan karakteristik air tanah pada lereng yang berbeda (Hendrayana et al, 2023). Lereng bagian barat Kompleks Gunungapi Bromo-Tengger terdapat wilayah industri di Kecamatan Kejayan dengan penggunaan air tanah sebesar 194 liter/detik.…”

An Analysis of Research Trends on Groundwater Utilization in Indonesia: A Bibliometric Study

“…Mount Merapi, which towers over the Indonesian Maritime Continent, is a beautiful natural panorama and a groundwater source for the surrounding population. The hydrogeological significance of Mount Merapi is manifested in the differences in groundwater characteristics in the southern and southeastern parts, forming a unique hydrological landscape [23]. Raimanuk, a potential agricultural area, shows the complexity of groundwater with different groups and hydraulic interconnections that influence land fertility [15].…”