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IDENTIFIKASI RONGGA MENGGUNAKAN METODE GEOLISTRIK KONFIGURASI DIPOLE-DIPOLE DAERAH NUSAKAMBANGAN CILACAP JAWA TENGAH Andi; Ajimas Pascaning Setiahadiwibowo
KURVATEK Vol 5 No 2 (2020): November 2020
Publisher : Institut Teknologi Nasional Yogyakarta

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.33579/krvtk.v5i2.2005

Abstract

The identification of cavities on Nusakambangan island using the geoelectrical resistivity method of dipole-dipole configuration has been carried out. This method was used for lateral resistivity mapping on each path. The geoelectric resistivity test was performed by four paths with a length of 200 - 400 m. The results showed that there were several closure patterns that were interpreted as cavities along the surveyed trajectory. The closure patterns are (i) three on path A with a resistivity of more than 4000 ohmmeters, (ii) two on path B with a resistivity of more than 10000 ohmmeters, (iii) one on path C with a resistivity of more than 10000 ohmmeters, and (iv) two on path D with a resistivity of more than 2000 ohmmeter. Our results could be used as an illustration to mark locations on the surface where the sinkhole potential of a disaster exists.Keywords: Cavity; Dipole-dipole; Geoelectric; Resistivity
Relocation of the Hypocenter of an Earthquake with the Double Difference Method in the Regional Study Area of Yogyakarta: Relokasi Hiposenter Gempabumi menggunakan Metode Double Difference Wilayah Kajian Daerah Istimewa Yogyakarta Fani Rohmiasih; Andi Andi; Nugroho Budi Wibowo
JURNAL GEOCELEBES Vol. 7 No. 2: October 2023
Publisher : Departemen Geofisika, FMIPA - Universitas Hasanuddin, Makassar

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.20956/geocelebes.v7i2.22223

Abstract

The relocation of the earthquake hypocentre is necessary in order to determine the position of the earthquake centre with higher accuracy. An accurate hypocentre position is important for earthquake-prone areas mapping, seismicity analysis, and fault zone identification. The double difference algorithm technique using the hypoDD program can be used for hypocentre relocation. This article reports the earthquake relocation of 23 earthquakes in the Yogyakarta region recorded at four observation stations. The result shows that the hypocentre shift spreads randomly with a shift distance of less than 20 km, with the most shifting direction of the epicentre to the northeast. The Earthquake’s hypocentre after relocation in the land area is estimated to be triggered by a fault under the Gamping Wungkal Formation, while the earthquake around Mount Merapi is estimated to be triggered by volcanic activity. The Relocation result in the sea area show that the hypocentre leads to the subduction line.
Analisis Zona Gerakan Tanah Menggunakan Metode Geolistrik Konfigurasi Wenner di Desa Gerbosari Kecamatan Samigaluh Nur Faqhina Mentari; Thaqibul Fikri Niyartama; Nugroho Budi Wibowo; Andi Andi
Wahana Fisika Vol 9, No 1 (2024): June
Publisher : Universitas Pendidikan Indonesia

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.17509/wafi.v9i1.68570

Abstract

Gerakan tanah di Desa Gerbosari berpotensi berdampak pada pemukiman dan fasilitas umum. Informasi mengenai litologi memiliki peran yang penting untuk mitigasi gerakan tanah yang akan terjadi. Penelitian ini bertujuan untuk mengetahui litologi dan zona gerakan tanah dengan metode geolistrik konfigurasi Wenner. Pengukuran geolistrik dilakukan sebanyak 7 lintasan pada zona berpotensi mengalami gerakan tanah. Panjang lintasan yang digunakan 300 m (5 lintasan), 260 m (1 lintasan) dan 240 m (1 lintasan). Pengolahan data menggunakan software Res2Dinv dan Surfer. Hasil pengolahan dari Res2Dinv berupa model penampang 2 dimensi yang menunjukkan nilai resistivitas daerah penelitian yaitu sebesar 0,481-636 Ωm. Daerah dengan zona rentan gerakan tanah yaitu pada resistivitas 0,481-151 Ωm (formasi Kebobutak) dan 0,481-8,52 Ωm (formasi Jonggarangan) yang diduga mengandung lempung dan batu pasir. Zona gerakan tanah tersebar hampir seluruh daerah penelitian, mulai dari kawasan penduduk hingga persawahan pada kedalaman 2,50-62,5 m. Land movement in Gerbosari Village has the potential to have an impact on settlements and public facilities. Information about lithology has an important role to mitigate soil movement that will occur. This study aims to determine the lithology and zone of ground movement with the Wenner configuration geoelectric method. Geoelectric measurements were carried out as many as 7 passes in the zone with the potential to experience ground movement. The track lengths used are 300 m (5 tracks), 260 m (1 track) and 240 m (1 track). Data processing using Res2Dinv and Surfer software. The processing results of Res2Dinv are in the form of a 2-dimensional cross-sectional model that shows the resistivity value of the research area, which is 0.481-636 Ωm. Areas with soil movement prone zones are at resistivities of 0.481-151 Ωm (Kebobutak formation) and 0.481-8.52 Ωm (Jonggarangan formation) which are thought to contain clay and sandstone. The soil movement zone is spread almost all over the study area, from populated areas to rice fields at a depth of 2.50-62.5 m. 
Pemodelan Peak Ground Accleration (PGA) dan Intensitas Gempabumi berdasarkan Pengukuran Mikrotremor pada Kawasan Longsor di Desa Kalongan, Ungaran Timur Nugroho Budi Wibowo; Thaqibul Fikri Niyartama; Andi Andi; Rena Septiana; Erlina Widianingrum; Ahdian Azri Bustari; Iktifal Ajie Arif
Jurnal Fisika Unand Vol 13 No 2 (2024)
Publisher : Universitas Andalas

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.25077/jfu.13.2.225-233.2024

Abstract

The landslide in Kalongan Village affected an area of 5 hectares and has the potential to experience further landslides. Landslides can occur with triggers of external factors such as earthquakes. The Peak Ground Acceleration (PGA) parameter can represent the impacts that occur on the surface in the form of earthquake intensity (MMI). Kalongan Village is 25.5km from the epicenter of the Ambarawa earthquake on 27 May 2023. This study aims to modeling the PGA microzonation and the intensity of the Ambarawa earthquake in the avalanche zone in Kalongan Village. The PGA model is based on measurements of 72 microtremor data in the avalanche zone using the Kanai method. Parameters of the Ambarawa earthquake with a magnitude of 2.5 and a depth of 5 km. The results of PGA modeling in the avalanche zone varied between 1.0-7.1 gal or I-II MMI values. The results of the PGA modeling show that aftershocks can occur if the strength of the Ambarawa earthquake reaches M=4 or 7.1-50.8 gal. The strength of the earthquake is equivalent to the intensity of II-V MMI.
Lithological Interpretation of Landslide Zone of Arjuna Road Kalongan Village East Ungaran Use Geomagnetic Method Bustari, Ahdian Azri; Andi, Andi; Wibowo, Nugroho Budi; Niyartama, Thaqibul Fikri
POSITRON Vol 14, No 2 (2024): Vol. 14 No. 2 Edition
Publisher : Fakultas Matematika dan Ilmu Pengetahuan Alam, Univetsitas Tanjungpura

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.26418/positron.v14i2.75655

Abstract

Arjuna Road in Kalongan Village, East Ungaran, which connects Semarang Regency with Demak Regency, has been cut off due to a landslide. Lithology as an internal controlling factor of landslide occurrence is important to be investigated. Research on the disaster has been conducted to determine the magnetic field anomaly and to interpret subsurface lithology using the geomagnetic method. The research was conducted on the landslide zone at Arjuna Road and its surrounding area using the geomagnetic method with looping data acquisition. The research area includes residential areas and plantation areas of residents with a research area of 1.3 × 0.8 km2 with a total of 104 measurement points. Through the results and analysis of the research, it can be determined that the magnetic field anomalies in the research area range from 17.1 - 882.2 nT where the landslide zone dominantly has a high anomaly indicating the closer the area is to bedrock, and for residential areas and local plantations, the magnetic field anomalies vary from low to high depending on the topography and sediment thickness in the area. In addition, the subsurface lithology in the study area consists of clay soil, claystone, tuff, and volcanic breccia. The impermeable nature of the tuff and the water-low permeable clay soil causes the boundary between the clay soil and tuff layers to become slippery when water seepage occurs, resulting the landslides.