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13 results on '"Yudistira, T"'

1. Crustal structure of Borneo, Makassar Strait and Sulawesi from ambient noise tomography

Author

Heryandoko, N, primary, Nugraha, A D, additional, Zulfakriza, Z, additional, Rosalia, S, additional, Yudistira, T, additional, Rohadi, S, additional, Daryono, D, additional, Supendi, P, additional, Nurpujiono, N, additional, Yusuf, F, additional, Fauzi, F, additional, Lesmana, A, additional, Husni, Y M, additional, Prayitno, B S, additional, Triyono, R, additional, Adi, S P, additional, Karnawati, D, additional, Greenfield, T, additional, Rawlinson, N, additional, and Widiyantoro, S, additional

Published
2024
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2. Limits of the seismogenic zone in the epicentral region of the 26 December 2004 great Sumatra-Andaman earthquake: Results from seismic refraction and wide-angle reflection surveys and thermal modeling

Author

Klingelhoefer, Frauke, Gutscher, Marc-André, Ladage, S., Dessa, J. -X., Graindorge, David, Franke, D., André, C., Permana, Haryadi, Yudistira, T., and Chauhan, Ajay

Subjects
Physics - Geophysics
Abstract

The 26 December 2004 Sumatra earthquake (Mw = 9.1) initiated around 30 km depth and ruptured 1300 km of the Indo-Australian Sunda plate boundary. During the Sumatra OBS (ocean bottom seismometer) survey, a wide angle seismic profile was acquired across the epicentral region. A seismic velocity model was obtained from combined travel time tomography and forward modeling. Together with reflection seismic data from the SeaCause II cruise, the deep structure of the source region of the great earthquake is revealed. Four to five kilometers of sediments overlie the oceanic crust at the trench, and the subducting slab can be imaged down to a depth of 35 km. We find a crystalline backstop 120 km from the trench axis, below the fore arc basin. A high velocity zone at the lower landward limit of the raycovered domain, at 22 km depth, marks a shallow continental Moho, 170 km from the trench. The deep structure obtained from the seismic data was used to construct a thermal model of the fore arc in order to predict the limits of the seismogenic zone along the plate boundary fault. Assuming 100C-150C as its updip limit, the seismogenic zone is predicted to begin 530 km from the trench. The downdip limit of the 2004 rupture as inferred from aftershocks is within the 350C 450C temperature range, but this limit is 210-250 km from the trench axis and is much deeper than the fore arc Moho. The deeper part of the rupture occurred along the contact between the mantle wedge and the downgoing plate.

Published
2010
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11. Shear wave velocity structure beneath Bandung basin, West Java, Indonesia from ambient noise tomography.

Author

Pranata, B, Yudistira, T, Widiyantoro, S, Brahmantyo, B, Cummins, P R, Saygin, E, Zulfakriza, Z, Rosalia, S, and Cipta, A

Subjects
*SURFACE waves (Seismic waves), *FRICTION velocity, *SHEAR waves, *SEISMIC wave velocity, *GROUP velocity dispersion, *GREEN'S functions
Abstract

We investigated the seismic shear wave velocity structure of the upper crust beneath the Bandung area in West Java, Indonesia, using ambient seismic noise tomography. We installed 60 seismographs to record ambient seismic noise continuously in the city of Bandung and its surrounding area for 8 months. After interstation cross-correlation of recordings of ambient seismic noise, we obtained empirical Green's functions for Rayleigh waves. Group velocity dispersion curves for Rayleigh waves between periods of 1  and 8 s were measured on each interstation path by applying the multiple filter analysis method with phase-matched processing. The spatial variation of group velocities shows a good correlation with the geological structure of the Bandung Basin. The Rayleigh wave dispersion maps were inverted to obtain the 1-D shear wave velocity profiles beneath each station, which were interpolated to infer a pseudo-3-D structure under the study region. The results show that the Bandung Basin has a thick layer of sediment. Along the northern, eastern and southern mountains surrounding the Bandung Basin there is high-velocity structure, except to the west of the Tangkuban Parahu volcano, where a massive low-velocity structure extending throughout the upper crust might indicate the presence of fluids or partial melts. [ABSTRACT FROM AUTHOR]

Published
2020
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12. The crustal structure beneath the Netherlands inferred from ambient seismic noise

Author

Yudistira, T., Trampert, J., Paulssen, J.A.M., and University Utrecht

Subjects
crust, tomography, surface waves, group velocity, ambient seismic noise, Netherlands
Abstract

A 3-D shear velocity model of the crust beneath the Netherlands is determined from fundamental mode Rayleigh and Love wave group measurements derived from ambient seismic noise recordings. The data are obtained from a temporary array of broad-band seismometers in and around the Netherlands (the NARS-Netherlands project, 2008-2012) complemented with data from existing networks in the Netherlands, Belgium and Germany. Rayleigh and Love wave group velocity maps were constructed for the period range of 10 to 30 s. The lateral variations in the group velocity maps primarily reflect variations in sedimentary thickness across the Netherlands. The 2ψ Rayleigh wave and 4ψ Love wave fast directions of the group velocity maps are in agreement with the NW-SE direction of maximum compressive stress as well as with the NW-SE dominant direction of faulting in the Netherlands. The frequency dependence suggests that the azimuthal anisotropy is caused by lattice preferred orientation (LPO) of lower crustal minerals. The 3-D shear-velocity model is obtained by inversion of the group velocity maps using the Neighborhood Algorithm. The results show a top layer that varies in thickness from 2 to 4 km with with a pattern that is similar to the base of the Rotliegend. A midcrustal discontinuity is found at a depth of about 13 km. The Moho appears to be relatively flat with an average depth of 33 km. Radial anisotropy is mainly positive (VSH - VSV > 0) for the lower crust. This can be an expression of LPO but also of horizontal layering or lamination. The top layer shows the largest variations in radial anisotropy with distinct areas of negative radial anisotropy that can be attributed to high-density near-vertical faulting in those regions.

Published
2015

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