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Subducted Lithospheric Boundary Tomographically Imaged Beneath Arc-Continent Collision in Eastern Indonesia
Harris C.W.a, Miller M.S.b, Supendi P.c, Widiyantoro S.d,e
a Department of Earth Science, University of Southern California, Los Angeles, United States
b Research School of Earth Sciences, Australian National University, Canberra, Australia
c Meteorological, Climatological, and Geophysical Agency (BMKG), Bandung, Indonesia
d Global Geophysics Research Group, Institut Teknologi Bandung, Bandung, Indonesia
e Faculty of Engineering, Maranatha Christian University Bandung, Bandung, Indonesia
[vc_row][vc_column][vc_row_inner][vc_column_inner][vc_separator css=”.vc_custom_1624529070653{padding-top: 30px !important;padding-bottom: 30px !important;}”][/vc_column_inner][/vc_row_inner][vc_row_inner layout=”boxed”][vc_column_inner width=”3/4″ css=”.vc_custom_1624695412187{border-right-width: 1px !important;border-right-color: #dddddd !important;border-right-style: solid !important;border-radius: 1px !important;}”][vc_empty_space][megatron_heading title=”Abstract” size=”size-sm” text_align=”text-left”][vc_column_text]©2020. American Geophysical Union. All Rights Reserved.We use traveltimes from a temporary seismic deployment of 30 broadband seismometers and a national catalog of arrival times to construct a finite-frequency teleseismic P-wave tomographic model of the upper mantle beneath eastern Indonesia, where subduction of the Indo-Australian plate beneath the Banda Arc transitions to arc-continent collision. The change in tectonics is due to a change from oceanic to continental lithosphere in the lower plate as inferred from geological mapping and geophysical, geochemical, and geodetic measurements. At this inferred transition, we seismically image the subducted continent-ocean boundary at upper mantle depths that links volcanism on Flores to amagmatic orogenesis on Timor. Our tomographic images reveal a relatively high-velocity feature within the upper mantle, which we interpret as the subducted Indo-Australian slab. The slab appears continuous yet deformed as a result of the change in buoyancy due to the composition of the incoming continental lithosphere. Accordingly, there is a difference in dip angle between the oceanic and continental sections of the slab albeit not a gap or discontinuity. We suggest the slab has deformed without tearing to accommodate structural and kinematic changes across the continent-ocean boundary as the two sections of the slab diverge. These results suggest that deformation in tectonic collisions can be localized along a continent-ocean boundary, even at depth. We propose that future slab tearing may develop where we observe slab deformation in our study region and that a similar process may take place in collisions generally.[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Author keywords” size=”size-sm” text_align=”text-left”][vc_column_text][/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Indexed keywords” size=”size-sm” text_align=”text-left”][vc_column_text]continental subduction,lithospheric deformation,P wave,subduction zone,tectonic collision,tomography[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Funding details” size=”size-sm” text_align=”text-left”][vc_column_text][{‘$’: “We would like to thank the (BMKG) for access to Indonesian earthquake catalogs. We also thank the (IPG) of Timor‐Leste, without their fieldwork support this work would not have been possible. Specifically, we would like to thank the field team, including Nova Roosmawati, Leland O’Driscoll, Eugénio Soares, Luís Teófilo da Costa, and Robert Porritt. This work was funded by the National Science Foundation (NSF) Grant EAR‐1250214 as well as DIKTI Grant 127/SP2H/PTNBH/DRPM/2018. All data used to create the velocity model in this publication are freely available for download on Dryad (doi: 10.5061/dryad.w3r2280mv ). Badan Meteorologi, Klimatologi, dan Geofisika Instituto do Petróleo e Geologia”}, {‘$’: “We would like to thank the Badan Meteorologi, Klimatologi, dan Geofisika (BMKG) for access to Indonesian earthquake catalogs. We also thank the Instituto do Petr?leo e Geologia (IPG) of Timor-Leste, without their fieldwork support this work would not have been possible. Specifically, we would like to thank the field team, including Nova Roosmawati, Leland O’Driscoll, Eug?nio Soares, Lu?s Te?filo da Costa, and Robert Porritt. This work was funded by the National Science Foundation (NSF) Grant EAR-1250214 as well as DIKTI Grant 127/SP2H/PTNBH/DRPM/2018. All data used to create the velocity model in this publication are freely available for download on Dryad (doi:10.5061/dryad.w3r2280mv).”}][/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”DOI” size=”size-sm” text_align=”text-left”][vc_column_text]https://doi.org/10.1029/2019JB018854[/vc_column_text][/vc_column_inner][vc_column_inner width=”1/4″][vc_column_text]Widget Plumx[/vc_column_text][/vc_column_inner][/vc_row_inner][/vc_column][/vc_row][vc_row][vc_column][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][/vc_column][/vc_row]