Subduction zone in Java Island using primary wave tomography from Jacobian relocation method based on ak135 velocity model

Listyaningrum, Risca; Muhlis, Faid; Soesilo, Joko; Palupi, Indriati Retno

doi:10.1063/1.4987053

Cited by 2 publications

(1 citation statement)

References 5 publications

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“…Hypocenter Relocation is required to repositioning the quake at coordinates x, y and depth z by subsurface velocity model using seismic data owned by ISC. Relocation process is conducted with the help of Matlab R2008b based on Jacobian matrix and ak135 velocity model [12]. Grid used is at the x coordinate is 20 km, the y coordinate is 10 km, while the z is variation from 5, 10 to 20 km adjusted with increasing depth, the greater the depth value (z).…”

Section: Methodsmentioning

confidence: 99%

Subsurface S-type Granitoid Identification Based on Gravity and Seismic Tomography Models in Pacitan, East Java

et al. 2019

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Granitoid outcrop has been observed in Montongan, Tulakan Subdistrict, Pacitan District, East Java. Geochemically, granitoid shows peralluminous S-type granitoid which consists of comparable plagioclase and potassium feldspar leading to adamelite and granodiorite variety with andalusite, fine size corundum and cordierite inside. These modal minerals are consistent with its bulk chemical analysis result that shows alumina rich rock. Highly weathered spotted pinkish soil with remaining quartz gravels characterizes its surface. Lateritic pink soil up to more than 25 meters thick covers the granitoid body and this feature is indicative to locate its surface distribution, while its subsurface distribution is remain uncertain. The research aimed to identify granitoid subsurface distribution. To identify the subsurface body, gravity and seismic tomography models were used. According gravity model, the pluton body is 5 km wide which is rootless downward and seems extends eastward. Meanwhile, the north-south seismic tomographic model across Pacitan Region indicates dense solid body override the recent Java subduction zone. The body is assumed to have correlation with surface granitic rock. It supports an idea that there is a micro continent trapped beneath Southern Mountain of East Java. ABSTRAK Singkapan granitoid telah teramati di daerah Montongan, Kecamatan Tulakan, Kabupaten Pacitan, Jawa Timur. Secara geokimia, granitoid Pacitan memperlihatkan granitoid peralumina tipe-S yang tersusun berdasarkan perbandingan plagioklas dan kalium felspar menunjuk pada varian adamelit dan granodiorit dengan andalusit, korundum halus dan kordierit di dalamnya. Mineral modal tersebut konsisten dengan hasil analisis kimia total yang menunjukkan batuan kaya alumina. Tanah berwarna merah muda yang sangat lapuk dengan kerikil sisa kuarsa menjadi ciri khas di permukaannya. Tanah laterit merah muda yang tebalnya lebih dari 25 meter menutupi tubuh granitoid tersebut dan menjadi petunjuk penyebaranya di permukaan, namun penyebaran di bawah permukaannya masih belum pasti. Penelitian ini bertujuan untuk mengetahui penyebaran granitoid di bawah permukaan. Untuk mengidentifikasi tubuh bawah permukaannya, digunakan pemodelan gravitasi dan tomografi seismik. Menurut model gravitasi tubuh pluton mempunyai lebar 5 km dan tampak memanjang ke arah timur yang tidak menentu ke bawahnya. Sementara itu, model tomografi seismik utara-selatan yang memotong wilayah Pacitan, menunjukkan suatu tubuh padat keras berada di atas zona subduksi Jawa saat ini. Tubuh tersebut diasumsikan memiliki hubungan dengan batuan granitik di permukaan. Hal tersebut mendukung ide bahwa terdapat mikro-kontinen terperangkap di bawah Pegunungan Selatan Jawa Timur.

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Section: Methodsmentioning

confidence: 99%

Subsurface S-type Granitoid Identification Based on Gravity and Seismic Tomography Models in Pacitan, East Java

et al. 2019

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First principles study of hydrogen bond symmetrization in δ-AlOOH

Pillai

Jha

Padmalal

et al. 2018

Journal of Applied Physics

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The high pressure behaviour of the hydrous mineral δ-AlOOH has been investigated by many experimental and theoretical studies, but the discrepancy in predicting the value of hydrogen symmetrization pressure was not resolved. Here, we investigated the high pressure behaviour of δ-AlOOH using first principles calculations and found that with proper optimization using pressure routine control, local density approximation (LDA) predicts the hydrogen symmetrization pressure as 15 GPa which is in good agreement with the experimentally predicted value which resolves the existing discrepancy and hence proving the validity of LDA in predicting the hydrogen symmetrization pressure. We further studied the compressibility behaviour of δ-AlOOH at low pressures and confirmed the P21nm to Pnnm transition of δ-AlOOH shown by the experimental work [Kuribayashi et al., Phys. Chem. Miner. 41, 303–312 (2014)]. We have also analysed the dependence of elastic constants, elastic moduli, sound velocities, and Raman spectrum of δ-AlOOH with pressure and found that a subtle change in the position of the hydrogen atom at hydrogen symmetrization pressure results into drastic changes in elastic and vibrational properties. Further, this study has been used to discuss the seismic anomalies observed in the upper mantle beneath the Deccan Volcanic Province in India and the Java subduction zone in the eastern flank of the Indian Ocean.

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Subduction zone in Java Island using primary wave tomography from Jacobian relocation method based on ak135 velocity model

Cited by 2 publications

References 5 publications

Subsurface S-type Granitoid Identification Based on Gravity and Seismic Tomography Models in Pacitan, East Java

Subsurface S-type Granitoid Identification Based on Gravity and Seismic Tomography Models in Pacitan, East Java

First principles study of hydrogen bond symmetrization in δ-AlOOH

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