Lower slope morphology of the Sumatra trench system

被引：36

作者：

Kopp, H. ^{[1
]}

Weinrebe, W. ^{[1
]}

Ladage, S. ^{[2
]}

Barckhausen, U. ^{[2
]}

Klaeschen, D. ^{[1
]}

Flueh, E. R. ^{[1
]}

Gaedicke, C. ^{[2
]}

Djajadihardja, Y. ^{[3
]}

Grevemeyer, I. ^{[1
]}

Krabbenhoeft, A. ^{[1
]}

Papenberg, C. ^{[1
]}

Zillmer, M. ^{[1
]}

机构：

[1] IFM GEOMAR, Leibniz Inst Marine Sci, Kiel, Germany

[2] BGR, Fed Inst Geosci & Nat Resources, Hannover, Germany

[3] BPPT, Agcy Assessment & Applicat Technol, Jakarta, Indonesia

来源：

BASIN RESEARCH | 2008年 / 20卷 / 04期

关键词：

D O I：

10.1111/j.1365-2117.2008.00381.x

中图分类号：

P [天文学、地球科学];

学科分类号：

07 ;

摘要：

At convergent margins, the structure of the subducting oceanic plate is one of the key factors controlling the morphology of the upper plate. We use high-resolution seafloor mapping and multichannel seismic reflection data along the accretionary Sumatra trench system to investigate the morphotectonic response of the upper plate to the subduction of lower plate fabric. Upper plate segmentation is reflected in varying modes of mass transfer. The deformation front in the southern Enggano segment is characterized by neotectonic formation of a broad and shallow fold-and-thrust belt consistent with the resumption of frontal sediment accretion in the wake of oceanic relief subduction. Conversely, surface erosion increasingly shapes the morphology of the lower slope and accretionary prism towards the north where significant oceanic relief is subducted. Subduction of the Investigator Fracture Zone and the fossil Wharton spreading centre in the Siberut segment exemplifies this. Such features also correlate with an irregularly trending deformation front suggesting active frontal erosion of the upper plate. Lower plate fabric extensively modulates upper plate morphology and the large-scale morphotectonic segmentation of the Sumatra trench system is linked to the subduction of reactivated fracture zones and aseismic ridges of the Wharton Basin. In general, increasing intensity of mass-wasting processes, from south to north, correlates with the extent of oversteepening of the lower slope (lower slope angle of 3.8 degrees in the south compared with 7.6 degrees in the north), probably in response to alternating phases of frontal accretion and sediment underthrusting. Accretionary mechanics thus pose a second-order factor in shaping upper plate morphology near the trench.

引用

页码：519 / 529

页数：11

共 35 条

[1] The June 2000 Mw 7.9 earthquakes south of Sumatra:: Deformation in the India-Australia Plate -: art. no. 2018 [J].