P and S velocity sturcture of the crust and the upper mantle beneath Central Java from local tomography inversion
| Autor: | Antonius Ratdomopurbo, Kirbani Sri Brotopuspito, Günter Asch, Nanang T. Puspito, M. A. Purbawinata, A. Manzanares, Birger Lühr, Heidrun Kopp, Wolfgang Rabbel, M. Bohm, Ivan Koulakov, E. Shevkunova, P. Fauzi |
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| Rok vydání: | 2007 |
| Předmět: |
Atmospheric Science
010504 meteorology & atmospheric sciences Mantle wedge Inversion (geology) Soil Science 550 - Earth sciences Aquatic Science Induced seismicity 010502 geochemistry & geophysics Oceanography 01 natural sciences Geochemistry and Petrology Earth and Planetary Sciences (miscellaneous) 0105 earth and related environmental sciences Earth-Surface Processes Water Science and Technology geography geography.geographical_feature_category Ecology Volcanic arc Subduction Anomaly (natural sciences) Paleontology Forestry Crust Geophysics Space and Planetary Science Slab Geology Seismology |
| Zdroj: | Journal of Geophysical Research: Solid Earth, 112 (B8). B08310. Journal of Geophysical Research |
| Popis: | Here we present the results of local source tomographic inversion beneath central Java. The data set was collected by a temporary seismic network. More than 100 stations were operated for almost half a year. About 13,000 P and S arrival times from 292 events were used to obtain three-dimensional (3-D) Vp, Vs, and Vp/Vs models of the crust and the mantle wedge beneath central Java. Source location and determination of the 3-D velocity models were performed simultaneously based on a new iterative tomographic algorithm, LOTOS-06. Final event locations clearly image the shape of the subduction zone beneath central Java. The dipping angle of the slab increases gradually from almost horizontal to about 70°. A double seismic zone is observed in the slab between 80 and 150 km depth. The most striking feature of the resulting P and S models is a pronounced low-velocity anomaly in the crust, just north of the volcanic arc (Merapi-Lawu anomaly (MLA)). An algorithm for estimation of the amplitude value, which is presented in the paper, shows that the difference between the fore arc and MLA velocities at a depth of 10 km reaches 30% and 36% in P and S models, respectively. The value of the Vp/Vs ratio inside the MLA is more than 1.9. This shows a probable high content of fluids and partial melts within the crust. In the upper mantle we observe an inclined low-velocity anomaly which links the cluster of seismicity at 100 km depth with MLA. This anomaly might reflect ascending paths of fluids released from the slab. The reliability of all these patterns was tested thoroughly. |
| Databáze: | OpenAIRE |
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