Seismic evidence for broken oceanic crust in the 2004 Sumatra earthquake epicentral region

Singh, S. C.; Carton, H. D.; Tapponnier, Paul; Hananto, Nugroho D.; Chauhan, A.; Hartoyo, Djoko; Bayly, Martin; Moeljopranoto, S.; Bunting, Tim; Christie, P. A. F.; Lubis, Hasbi; Martin, James

doi:10.1038/ngeo336

Cited by 122 publications

(142 citation statements)

References 27 publications

Supporting

Mentioning

132

Contrasting

Unclassified

Order By: Relevance

“…1). The thrust events observed after the 2004 earthquake at the subduction front were attributed to a strong coupling between the subducting plate and the overriding plate up to the subduction front, and consequently the seaward propagation of the megathrust rupture up to the trench 21,23 . The bathymetry and seismic reflection data indicate that most of the dip-slip faults along F6 and F7 have N-S strike, not trench parallel as expected for bending related faulting.…”

Section: Discussionmentioning

confidence: 99%

“…It covers the entire segment of the oceanic crust, bounded by two fracture zones, F5 and F6 that lie at the southeast and northwest ends of the profile, respectively. WG2 was shot traversing the subduction zone orthogonally with a direction of N38°E crossing the whole subduction system 21,58 . Here we only show the oceanic part of the profile (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…A marine seismic survey was conducted offshore northern Sumatra in 2006 to investigate the structural properties of the Sumatra subduction zone 21 . Our study area is located B100 km north of the 2012 main shock, close to the 10 January foreshock.…”

mentioning

confidence: 99%

See 2 more Smart Citations

Seismic evidence of a two-layer lithospheric deformation in the Indian Ocean

Qin

Singh

2015

Nat Commun

View full text Add to dashboard Cite

Intra-plate deformation and associated earthquakes are enigmatic features on the Earth. The Wharton Basin in the Indian Ocean is one of the most active intra-plate deformation zones, confirmed by the occurrence of the 2012 great earthquakes (MwZ8.2). These earthquakes seem to have ruptured the whole lithosphere, but how this deformation is distributed at depth remains unknown. Here we present seismic reflection images that show faults down to 45 km depth. The amplitude of these reflections in the mantle first decreases with depth down to 25 km and then remains constant down to 45 km. The number of faults imaged along the profile and the number of earthquakes as a function of depth show a similar pattern, suggesting that the lithospheric mantle deformation can be divided into two layers: a highly fractured fluid-filled serpentinized upper layer and a pristine brittle lithospheric mantle where great earthquakes initiate and large stress drops occur.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Seismic evidence of a two-layer lithospheric deformation in the Indian Ocean

Qin

Singh

2015

Nat Commun

View full text Add to dashboard Cite

show abstract

“…In the tectonic environment of subduction zones, shear zones can reach down to mantle depth as continuation of seismically active fault zones, as for example observed for the Sumatra earthquake in 2004 that caused the infamous tsunami (Singh et al, 2008;Dessa et al, 2009). The macroscale time-dependent rheology of such shear zones is controlled by nano-to micro-scale deformation and recrystallization processes in the affected upper mantle rocks (i.e., peridotites).…”

Section: Introductionmentioning

confidence: 99%

Experimental deformation and recrystallization of olivine – processes and timescales of damage healing during postseismic relaxation at mantle depths

Trepmann¹,

Renner

Druiventak

2013

Solid Earth

View full text Add to dashboard Cite

Abstract. Experiments comprising sequences of deformation (at 300 or 600 • C) and annealing at varying temperature (700 to 1100 • C), time (up to 144 h) and stress (up to 1.5 GPa) were carried out in a Griggs-type apparatus on natural olivine-rich peridotite samples to simulate deformation and recrystallization processes in deep shear zones that reach mantle depth as continuations of seismically active faults. The resulting olivine microfabrics were analysed by polarization and electron microscopy (SEM/EBSD, TEM). Core-and-mantle-like microstructures are the predominant result of our experiments simulating rapid stress relaxation (without or with minor creep) after a high-stress deformation event: porphyroclasts (> 100 µm) are surrounded by new grains comprising fragments and recrystallized grains with a wide range in size (2 to 40 µm). Areas with small grains (≤ 10 µm) trace former high-strain zones generated during initial high-stress deformation even after annealing at a temperature of 1100 • C for 70 h. A weak crystallographic preferred orientation (CPO) of new olivine grains is related to the orientation of the original host crystals but appears unrelated to the strain field. Based on these findings, we propose that olivine microstructures in natural shear-zone peridotites with a large range in grain size, localized fine-grained zones, and a weak CPO not related to the strain field are diagnostic for a sequence of high-stress deformation followed by recrystallization at low stresses, as to be expected in areas of seismic activity. We extended the classic Avrami-kinetics equation by accounting for time-dependent growth kinetics and constrained the involved parameters relying on our results and previous studies devoted to the kinetics of defect processes in olivine. Extrapolation to natural conditions suggests that the observed characteristic microstructure may develop within as little as tens of years and less than ten thousands of years. These recrystallization microstructures have a great diagnostic potential for past seismic activity because they are expected to be stable over geological timescales, since driving forces for further modification are not sufficient to erase the characteristic heterogeneities.

show abstract

“…However, there are three problems in imaging such a rupture plane in subduction zone environments: (1) poor penetration of seismic energy through thick sediments, (2) scattering from rough seafl oor surface, and (3) reverberations of seismic energy in the water column, which are called multiples. For deep penetration of energy, a low-frequency energy source is required, whereas long-offset data are required to remove multiples [Singh et al, 2008].…”

Section: Seismic Reflection Surveymentioning

confidence: 99%

Eos, Transactions, American Geophysical Union Volume 90, Number 49, 8 December 2009

2009

EoS Transactions

View full text Add to dashboard Cite

Seismic evidence for broken oceanic crust in the 2004 Sumatra earthquake epicentral region

Cited by 122 publications

References 27 publications

Seismic evidence of a two-layer lithospheric deformation in the Indian Ocean

Seismic evidence of a two-layer lithospheric deformation in the Indian Ocean

Experimental deformation and recrystallization of olivine – processes and timescales of damage healing during postseismic relaxation at mantle depths

Eos, Transactions, American Geophysical Union Volume 90, Number 49, 8 December 2009

Contact Info

Product

Resources

About