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Journal : Jurnal Pendidikan, Sains, Geologi, dan Geofisika (GeoScienceEd Journal)

Analysis Of Seismic Rate Change Based On Spatial Distribution Of Seismotectonics And Deformation Extension In West Nusa Tenggara Aprimanda Mulya Rizki, Rifa; Syafriani; Amir, Harman; Zulhendra, Zulhendra
Jurnal Pendidikan, Sains, Geologi, dan Geofisika (GeoScienceEd Journal) Vol. 6 No. 1 (2025): Februari
Publisher : Mataram University

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Wilayah Nusa Tenggara Barat memiliki aktivitas kegempaan yang tinggi. Sebelum terjadinya suatu kejadian gempa bumi, terlebih dahulu didahului oleh keadaan seismik tenang. Tujuan dari penelitian ini untuk mengetahui perubahan laju seismik yang diamati dari fenomena seismik tenang dan luas deformasi. Metode perubahan laju seismik yang digunakan adalah distribusi spasial z-value. Dan metode luas deformasi yang digunakan adalah rumusan Utsu dan Seki untuk gempa bumi M7,0 pada tanggal 5 Agustus 2018 dengan input magnitudo permukaan. Penelitian ini menggunakan data dari website USGS periode 1983-2023. Pada penelitian ini terdapat tiga zona fokus penelitian yaitu gempa bumi tahun 2009 (M6,6), gempa bumi tahun 2018 (M7,0) dan gempa bumi tahun 2018 (M6,9). Dengan menggunakan metode distribusi spasial z-value, wilayah dibagi menjadi beberapa grid. Nilai z dihitung pada setiap grid dan menggambarkan perubahan laju seismik. Fenomena tersebut dapat dilihat berdasarkan perubahan laju seismik yang telah diperoleh. Hasil yang diperoleh, pada zona pertama terjadi peningkatan aktivitas seismik sebelum gempa bumi 2009, zona kedua dan zona ketiga terjadi fenomena seismic quiescence yang mendahului gempa bumi 2018. Berdasarkan sebaran spasial z-value awal tahun 2023, terjadi fenomena penurunan aktivitas seismik di sebagian wilayah Nusa Tenggara Barat. Serta terjadi deformasi sebesar 1.091,44 km2 pada gempa bumi M7,0 tanggal 5 Agustus 2018. Hal ini patut diduga sebagai awal gejala gempa bumi di masa mendatang .
Analysis Of Seismic Quiescence Precursors Before The M7.4 Earthquake Of 28 September 2018 In Central Sulawesi Based On Seismotectonic Spatial Distribution And Earthquake Fracture Lengths zu, Zurahma; Syafriani; Dwiridal, Letmi; Zulhendra, Zulhendra
Jurnal Pendidikan, Sains, Geologi, dan Geofisika (GeoScienceEd Journal) Vol. 6 No. 1 (2025): Februari
Publisher : Mataram University

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

The Central Sulawesi earthquake with coordinates 2°30‘S -1°50’ N and 119°0'-124°20 E magnitude 7.4 in Palu, Donggala Regency on 28 September 2018. This earthquake was a significant and destructive earthquake in Central Sulawesi. A significant earthquake is preceded by a seismic quiescence. The aim of the study was to determine when the seismic quiescence occurred and seismic activity after the earthquake alongside fracture length. The method of analysis of seismic quiescence and fracture length is z-value and Wells and Coppersmith equation. Data processed with MATLAB and Zmap were 1478 events from 1983-2023. The study area is divided into several grids with sizes of 0.1°* 0.1°. The number of earthquakes included (N = 800, 700, 600, 500, 400, 300, and 200). The z-value was calculated for each grid based on the earthquake data organized in one grid and seismic activity after earthquake. The results of the analysis of the z-value calculation in each grid show of seismic quiescence before a significant earthquake. Based on the results of the spatial distribution of z-value in Central Sulawesi, the seismic quiescence preceded the 28 September 2018 earthquake event (M 7.4) by about 21 years beginning in 1990. When cut at 2019.6, there was a decrease in seismic activity again, which indicated that an earthquake would occur, so it was thought to be a trigger factor for future earthquake precursors. While the fracture length of the 7.4 Mw earthquake of 104,232 meters shows a positive correlation between magnitude and fracture length.
Estimation Of Maximum Ground Acceleration Value Based On Mentawai Earthquake Scenario Using Atkinson Boore and Zhao Khairunnissa, Shafira; Syafriani; Fauzi, Ahmad; Zulhendra, Zulhendra
Jurnal Pendidikan, Sains, Geologi, dan Geofisika (GeoScienceEd Journal) Vol. 5 No. 4 (2024): November
Publisher : Mataram University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/goescienceed.v5i4.510

Abstract

We have estimated the value and intensity of maximum ground acceleration in West Sumatra based on the Mentawai earthquake scenario by using the formulation of Atkinson Boore (2003) and Zhao (2006). This study aims to determine the PGA value of an area as the level of activity and intensity of the earthquake in West Sumatra region from the Mentawai earthquake scenario as a measure of damage caused by the earthquake and analyze its distribution. This study uses earthquake information data for the period 1900-2023 with magnitude > 7 SR and depth < 100 km and shear wave velocity model at a depth of 30 meters (Vs 30) sourced from the National Earthquakes Information Center US Geological Survey (NEIC/USGS) catalog. After that, calculations are carried out so that the estimated maximum ground acceleration value is obtained using the Atkinson Boore (2003) and Zhao (2006) formulas. The maximum ground acceleration and earthquake intensity values for each city/regency in West Sumatra were calculated with a 0.1° grid. The estimation results show that the largest values for each scenario are in Mentawai Islands and South Pesisir because those areas are close to the subduction zone. In addition, it is also influenced by the epicenter, magnitude and soil type in the region. So that the maximum ground acceleration value in West Sumatra ranges from 0.007 g - 2.117 g with earthquake intensity ranging from I - X+ MMI. This indicates that the area is vulnerable to damage if an earthquake occurs. Keywords: Earthquakes, Atkinson Boore, Zhao, PGA, Intensity
Analysis of Seismicity and Return Period of Earthquakes in South Pesisir Regency West Sumatra Province Using the Likelihood Method Husna, Azmi Asmaul; Syafriani; Hamdi; Letmi Dwiridal
Jurnal Pendidikan, Sains, Geologi, dan Geofisika (GeoScienceEd Journal) Vol. 6 No. 1 (2025): Februari
Publisher : Mataram University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/goescienceed.v6i1.589

Abstract

The South Pesisir area was one of the areas that was rocked by an earthquake on September 30, 2009. The earthquake that occurred caused damage and loss of life. Based on these conditions, the South Pesisir Regency area was identified as an earthquake-prone area. Therefore, it is necessary to research seismicity and return period in the regency. This research used the statistical likelihood method to determine the accumulated rock stress, seismcity and return period of eartquakes. The data used is earthquake data for the period 1934-2023 with a magnitude ≥4 SR and a depth of ≤300 km. The results of this research provided an overview of the seismicity and return period in the South Pesisir Regency. Seismicity was determined based on rock stress condition (b-value) and on the level seismic activity (a-value). Based on calculations showed that the a-value and b-value for the 20-year and 90-year intervals ranged between 6.16-10.9 and 0.953-2.17, respectively. Earthquakes return periods at intervals of 20 years and 90 years for the magnitude range 4.0-4.4 produced almost the same return period, namely less than one year. Meanwhile, earthquakes with magnitudes of 4.5-6 had recurrence periods ranging from 1 to 63 years.
Analysis Of Seismic Rate Change Based On Spatial Distribution Of Seismotectonics And Deformation Extension In West Nusa Tenggara Aprimanda Mulya Rizki, Rifa; Syafriani; Amir, Harman; Zulhendra, Zulhendra
Jurnal Pendidikan, Sains, Geologi, dan Geofisika (GeoScienceEd Journal) Vol. 6 No. 1 (2025): Februari
Publisher : Mataram University

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

Wilayah Nusa Tenggara Barat memiliki aktivitas kegempaan yang tinggi. Sebelum terjadinya suatu kejadian gempa bumi, terlebih dahulu didahului oleh keadaan seismik tenang. Tujuan dari penelitian ini untuk mengetahui perubahan laju seismik yang diamati dari fenomena seismik tenang dan luas deformasi. Metode perubahan laju seismik yang digunakan adalah distribusi spasial z-value. Dan metode luas deformasi yang digunakan adalah rumusan Utsu dan Seki untuk gempa bumi M7,0 pada tanggal 5 Agustus 2018 dengan input magnitudo permukaan. Penelitian ini menggunakan data dari website USGS periode 1983-2023. Pada penelitian ini terdapat tiga zona fokus penelitian yaitu gempa bumi tahun 2009 (M6,6), gempa bumi tahun 2018 (M7,0) dan gempa bumi tahun 2018 (M6,9). Dengan menggunakan metode distribusi spasial z-value, wilayah dibagi menjadi beberapa grid. Nilai z dihitung pada setiap grid dan menggambarkan perubahan laju seismik. Fenomena tersebut dapat dilihat berdasarkan perubahan laju seismik yang telah diperoleh. Hasil yang diperoleh, pada zona pertama terjadi peningkatan aktivitas seismik sebelum gempa bumi 2009, zona kedua dan zona ketiga terjadi fenomena seismic quiescence yang mendahului gempa bumi 2018. Berdasarkan sebaran spasial z-value awal tahun 2023, terjadi fenomena penurunan aktivitas seismik di sebagian wilayah Nusa Tenggara Barat. Serta terjadi deformasi sebesar 1.091,44 km2 pada gempa bumi M7,0 tanggal 5 Agustus 2018. Hal ini patut diduga sebagai awal gejala gempa bumi di masa mendatang .
Analysis Of Seismic Quiescence Precursors Before The M7.4 Earthquake Of 28 September 2018 In Central Sulawesi Based On Seismotectonic Spatial Distribution And Earthquake Fracture Lengths zu, Zurahma; Syafriani; Dwiridal, Letmi; Zulhendra, Zulhendra
Jurnal Pendidikan, Sains, Geologi, dan Geofisika (GeoScienceEd Journal) Vol. 6 No. 1 (2025): Februari
Publisher : Mataram University

Show Abstract | Download Original | Original Source | Check in Google Scholar

Abstract

The Central Sulawesi earthquake with coordinates 2°30‘S -1°50’ N and 119°0'-124°20 E magnitude 7.4 in Palu, Donggala Regency on 28 September 2018. This earthquake was a significant and destructive earthquake in Central Sulawesi. A significant earthquake is preceded by a seismic quiescence. The aim of the study was to determine when the seismic quiescence occurred and seismic activity after the earthquake alongside fracture length. The method of analysis of seismic quiescence and fracture length is z-value and Wells and Coppersmith equation. Data processed with MATLAB and Zmap were 1478 events from 1983-2023. The study area is divided into several grids with sizes of 0.1°* 0.1°. The number of earthquakes included (N = 800, 700, 600, 500, 400, 300, and 200). The z-value was calculated for each grid based on the earthquake data organized in one grid and seismic activity after earthquake. The results of the analysis of the z-value calculation in each grid show of seismic quiescence before a significant earthquake. Based on the results of the spatial distribution of z-value in Central Sulawesi, the seismic quiescence preceded the 28 September 2018 earthquake event (M 7.4) by about 21 years beginning in 1990. When cut at 2019.6, there was a decrease in seismic activity again, which indicated that an earthquake would occur, so it was thought to be a trigger factor for future earthquake precursors. While the fracture length of the 7.4 Mw earthquake of 104,232 meters shows a positive correlation between magnitude and fracture length.
Estimation Of Maximum Ground Acceleration Value Based On Mentawai Earthquake Scenario Using Atkinson Boore and Zhao Khairunnissa, Shafira; Syafriani; Fauzi, Ahmad; Zulhendra, Zulhendra
Jurnal Pendidikan, Sains, Geologi, dan Geofisika (GeoScienceEd Journal) Vol. 5 No. 4 (2024): November
Publisher : Mataram University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/goescienceed.v5i4.510

Abstract

We have estimated the value and intensity of maximum ground acceleration in West Sumatra based on the Mentawai earthquake scenario by using the formulation of Atkinson Boore (2003) and Zhao (2006). This study aims to determine the PGA value of an area as the level of activity and intensity of the earthquake in West Sumatra region from the Mentawai earthquake scenario as a measure of damage caused by the earthquake and analyze its distribution. This study uses earthquake information data for the period 1900-2023 with magnitude > 7 SR and depth < 100 km and shear wave velocity model at a depth of 30 meters (Vs 30) sourced from the National Earthquakes Information Center US Geological Survey (NEIC/USGS) catalog. After that, calculations are carried out so that the estimated maximum ground acceleration value is obtained using the Atkinson Boore (2003) and Zhao (2006) formulas. The maximum ground acceleration and earthquake intensity values for each city/regency in West Sumatra were calculated with a 0.1° grid. The estimation results show that the largest values for each scenario are in Mentawai Islands and South Pesisir because those areas are close to the subduction zone. In addition, it is also influenced by the epicenter, magnitude and soil type in the region. So that the maximum ground acceleration value in West Sumatra ranges from 0.007 g - 2.117 g with earthquake intensity ranging from I - X+ MMI. This indicates that the area is vulnerable to damage if an earthquake occurs. Keywords: Earthquakes, Atkinson Boore, Zhao, PGA, Intensity
Analysis of Seismicity and Return Period of Earthquakes in South Pesisir Regency West Sumatra Province Using the Likelihood Method Husna, Azmi Asmaul; Syafriani; Hamdi; Letmi Dwiridal
Jurnal Pendidikan, Sains, Geologi, dan Geofisika (GeoScienceEd Journal) Vol. 6 No. 1 (2025): Februari
Publisher : Mataram University

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.29303/goescienceed.v6i1.589

Abstract

The South Pesisir area was one of the areas that was rocked by an earthquake on September 30, 2009. The earthquake that occurred caused damage and loss of life. Based on these conditions, the South Pesisir Regency area was identified as an earthquake-prone area. Therefore, it is necessary to research seismicity and return period in the regency. This research used the statistical likelihood method to determine the accumulated rock stress, seismcity and return period of eartquakes. The data used is earthquake data for the period 1934-2023 with a magnitude ≥4 SR and a depth of ≤300 km. The results of this research provided an overview of the seismicity and return period in the South Pesisir Regency. Seismicity was determined based on rock stress condition (b-value) and on the level seismic activity (a-value). Based on calculations showed that the a-value and b-value for the 20-year and 90-year intervals ranged between 6.16-10.9 and 0.953-2.17, respectively. Earthquakes return periods at intervals of 20 years and 90 years for the magnitude range 4.0-4.4 produced almost the same return period, namely less than one year. Meanwhile, earthquakes with magnitudes of 4.5-6 had recurrence periods ranging from 1 to 63 years.