Correspondence |
Featured
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Letter |
Experimental evidence that thrust earthquake ruptures might open faults
Earthquake rupture experiments and mathematical modelling reveal the existence of a torquing mechanism of thrust fault ruptures near the free surface that causes them to dynamically unclamp, open and slip large distances.
- Vahe Gabuchian
- , Ares J. Rosakis
- & Hiroo Kanamori
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Research Highlights |
Quake shows rare complexity
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Letter |
Evidence for a Fe3+-rich pyrolitic lower mantle from (Al,Fe)-bearing bridgmanite elasticity data
The authors report single-crystal elasticity data on (Al,Fe)-bearing bridgmanite and show that its elastic behaviour is markedly different from that of the MgSiO3 endmember.
- A. Kurnosov
- , H. Marquardt
- & L. Ziberna
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Letter |
Rheological separation of the megathrust seismogenic zone and episodic tremor and slip
A model of the conditions required for episodic tremor and accompanying slow slip to occur, near the megathrust seismogenic zone, reconciles seemingly contradictory observations.
- Xiang Gao
- & Kelin Wang
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News |
Long-awaited mathematics proof could help scan Earth's innards
Proposed solution to geometry puzzle allows an object’s structure to be determined from limited information.
- Davide Castelvecchi
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Research Highlights |
Gravity changes before quake hits
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Letter |
Dynamics of a seafloor-spreading episode at the East Pacific Rise
Seismic observations clarify the roles of magma pressure and tectonic stress in the development of seafloor spreading during the most recent eruption at the East Pacific Rise.
- Yen Joe Tan
- , Maya Tolstoy
- & William S. D. Wilcock
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Letter |
Asthenosphere rheology inferred from observations of the 2012 Indian Ocean earthquake
Analysis of the postseismic deformation of the moment magnitude 8.6 Indian Ocean earthquake in 2012 reveals that the asthenospheric layer must be thin and of low viscosity, constraining the structure of oceanic upper-mantle rheology.
- Yan Hu
- , Roland Bürgmann
- & Kelin Wang
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News |
Italian scientists shocked by earthquake devastation
In a region known to be seismically active, destruction on this scale was still a surprise.
- Alison Abbott
- & Quirin Schiermeier
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News |
'Terrifying shaking': Deadly Italian quake strikes 40 kilometres from L’Aquila
Unlike 2009 tragedy, no seismic activity was recorded prior to the latest quake.
- Quirin Schiermeier
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Letter |
High-resolution seismic constraints on flow dynamics in the oceanic asthenosphere
Rayleigh waves recorded with an ocean-bottom seismograph array in the central Pacific Ocean constrain the seismic anisotropy within the oceanic lithosphere–asthenosphere system: seafloor-spreading-induced lithospheric fabric generates the strongest anisotropy, while density- and/or pressure-driven flow produces a secondary peak in anisotropy at the base of the asthenosphere.
- Pei-Ying Patty Lin
- , James B. Gaherty
- & Greg Hirth
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Letter |
Mid-ocean-ridge seismicity reveals extreme types of ocean lithosphere
The structure and accretion modes of two end-member types of oceanic lithosphere are described using a detailed seismicity survey along 390 kilometres of an ultraslow ridge axis, indicating deeper seismicity in amagmatic regions and explaining the uneven crustal production at ultraslow-spreading ridges.
- Vera Schlindwein
- & Florian Schmid
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News |
Canadian earthquake detector has deep-sea edge over US rival
Sea-floor instruments will monitor seismic activity very close to the Cascadia fault.
- Nicola Jones
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Books & Arts |
Books in brief
Barbara Kiser reviews five of the week's best science picks.
- Barbara Kiser
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Books & Arts |
Astronomy: Cosmic detectives
Bernie Fanaroff surveys a study that probes telescopes in history and across the electromagnetic spectrum.
- Bernie Fanaroff
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Letter |
Seafloor geodetic constraints on interplate coupling of the Nankai Trough megathrust zone
Seafloor geodetic data from the Nankai Trough, off southwestern Japan, show that most offshore sites in this earthquake-prone region have high slip-deficit rates, revealing previously unknown locations that could be important for the mitigation of future earthquake- and tsunami-associated disasters.
- Yusuke Yokota
- , Tadashi Ishikawa
- & Akira Asada
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Letter |
The Parkfield tremors reveal slow and fast ruptures on the same asperity
A tremor source on the San Andreas Fault produced an unusual sequence of low-frequency earthquakes until it was disrupted by the 2004 Parkfield earthquake; the peculiar recurrence pattern has now been modelled, showing that such slip behaviour occurs when the tremor asperity size is close to the critical nucleation size of earthquakes.
- Deepa Mele Veedu
- & Sylvain Barbot
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News |
NASA Mars woes could delay other planetary missions
Plan to postpone launch of InSight probe will cost agency an extra US$150 million.
- Devin Powell
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Letter |
Upper-plate controls on co-seismic slip in the 2011 magnitude 9.0 Tohoku-oki earthquake
Residual topography and gravity anomalies reveal a tectonic boundary in northeast Japan, which is proposed to represent the offshore continuation of the Median Tectonic Line; the contrast in frictional properties across this structure may control earthquake behaviour there, as recently demonstrated by the giant 2011 Tohoku-oki earthquake.
- Dan Bassett
- , David T. Sandwell
- & Anthony B. Watts
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Research Highlights |
Unnatural shaking in California
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Letter |
Dehydration of lawsonite could directly trigger earthquakes in subducting oceanic crust
Deformation experiments on lawsonite reveal that unstable fault slip occurs during dehydration reactions with continuous acoustic emission signals; this indicates the potential for unstable frictional sliding in natural lawsonite layers, which could possibly be the source of intermediate-depth earthquakes in cold subduction zones.
- Keishi Okazaki
- & Greg Hirth
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News |
In Japan, small shakes presage big quakes
Clusters of slow-slip events linked to risk of larger ones.
- Alexandra Witze
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Research Highlights |
Mediterranean quake risk rises
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Letter |
Scale dependence of rock friction at high work rate
In metre-sized rock specimens, rock friction starts to decrease at a much smaller work rate than in centimetre-sized rock specimens, thus demonstrating that rock friction is scale-dependent.
- Futoshi Yamashita
- , Eiichi Fukuyama
- & Hironori Kawakata
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News |
Tsunami researchers watch for waves from Chile quake
8.3-magnitude earthquake causes relatively little damage, including to nation's telescopes.
- Quirin Schiermeier
- & Elizabeth Gibney
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Letter |
Lithospheric controls on magma composition along Earth’s longest continental hotspot track
A 2,000-kilometre-long volcanic hotspot track is identified in eastern Australia, along which magma composition and volcanic outcrop show a strong correlation with lithospheric thickness, providing an observational constraint on the sub-continental melting depth of mantle plumes.
- D. R. Davies
- , N. Rawlinson
- & I. H. Campbell
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Letter |
Broad plumes rooted at the base of the Earth's mantle beneath major hotspots
A whole-mantle seismic imaging technique, combining accurate wavefield computations with information contained in whole seismic waveforms, is used to reveal the presence of broad conduits beneath many of Earth’s surface hotspots, supporting the idea that these conduits are the source of hotspot volcanoes.
- Scott W. French
- & Barbara Romanowicz
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Letter |
Western US intermountain seismicity caused by changes in upper mantle flow
Results from mantle flow models reveal a relationship between seismicity away from the plate boundary in the western United States and the rate change of the vertical normal stress from mantle flow, showing that mantle flow plays an important part in shaping topography, tectonics and seismic hazard within such intraplate settings.
- Thorsten W. Becker
- , Anthony R. Lowry
- & Chunquan Yu
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Letter |
The role of ridges in the formation and longevity of flat slabs
Flat-slab subduction is often proposed to cause deformation of continental crust far from plate boundaries as well as unusual patterns of volcanism; a study of the largest-known flat slab, located in Peru, now shows that the ridge is necessary for the formation and longevity of the flat slab, whereas other contributing factors such as trench retreat and suction alone will not suffice.
- Sanja Knezevic Antonijevic
- , Lara S. Wagner
- & Cristobal Condori
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News |
Podcast: Geologists on quake alert, banishing HIV and a volcano mystery solved
Nature's weekly audio round-up.
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News Q&A |
Nuclear monitoring agency reaches out to scientists
Geophysicist Lassina Zerbo discusses the goals of the Comprehensive Nuclear-Test-Ban Treaty Organization, and how researchers are using his organization's data.
- Davide Castelvecchi
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News |
Wastewater disposal causes sharp rise in central US earthquakes
Nearly 90% of region's quakes now caused by water injected into underground wells.
- Alexandra Witze
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News |
Fluid injection causes ground to creep before quakes
Monitoring rock movement could help to prevent seismic activity caused by energy exploration.
- Alexandra Witze
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Correspondence |
Improve oversight of fracking in China
- Hong Yang
- , Julian R. Thompson
- & Roger J. Flower
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Research Highlights |
New islands reveal Red Sea rifting
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Research Highlights |
Crust crunch leads to huge quakes
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News Q&A |
How scientists are aiding quake recovery in Nepal
Geologist Pradeep Mool talks about the aftermath of the magnitude-7.8 event near Kathmandu.
- Jane Qiu
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News Explainer |
Major earthquake hits Nepal
Scientists have long warned that mounting seismic stress put region near Kathmandu at risk for a severe tremor.
- Alexandra Witze
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Research Highlights |
San Francisco's quake hazard rises
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Letter |
A seismic reflection image for the base of a tectonic plate
A high-resolution image for the base of an oceanic plate that is subducting beneath North Island, New Zealand, reveals a channel, which is interpreted as a sheared zone of ponded partial melts or volatiles; this low-viscosity channel decouples the plate from mantle flow beneath, allowing plate tectonics to work.
- T. A. Stern
- , S. A. Henrys
- & T. Iwasaki
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Letter |
Seismic evidence of effects of water on melt transport in the Lau back-arc mantle
Tomographically derived seismic velocities are used to infer the distribution of partial melt below the Lau Basin, revealing an unexpected relationship between the amount of in situ melt and the water content of the magma, indicating that subducted water enhances melt extraction.
- S. Shawn Wei
- , Douglas A. Wiens
- & James A. Conder
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Letter |
Subduction-driven recycling of continental margin lithosphere
Seismic images of the subducted Atlantic slab under northeastern South America and the Alboran slab beneath the Gibraltar arc region show that subducting oceanic plates viscously entrain and remove the bottom of the continental thermal boundary layer from adjacent continental margins, driving surface tectonics and pre-conditioning the margins for further deformation.
- A. Levander
- , M. J. Bezada
- & M. S. Miller
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Letter |
Prevalence of viscoelastic relaxation after the 2011 Tohoku-oki earthquake
Seafloor Global Positioning System observations immediately after the great 2011 Tohoku-oki earthquake provide unambiguous evidence for the dominant role of viscoelastic relaxation in short-term postseismic deformation, rather than just afterslip on the fault as is commonly assumed.
- Tianhaozhe Sun
- , Kelin Wang
- & Yan Hu
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Letter |
Continuing megathrust earthquake potential in Chile after the 2014 Iquique earthquake
The 2014 Iquique event was not the earthquake that had been expected to fill the regional seismic gap; given that significant sections of the northern Chile subduction zone have not ruptured in almost 150 years, it is likely that future megathrust earthquakes will occur south and potentially north of the 2014 Iquique sequence.
- Gavin P. Hayes
- , Matthew W. Herman
- & Sergey Samsonov
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Letter |
Gradual unlocking of plate boundary controlled initiation of the 2014 Iquique earthquake
A long foreshock series unlocked the South American plate boundary until eventually initiating the M 8.1 Iquique, Chile, earthquake.
- Bernd Schurr
- , Günter Asch
- & Jean-Pierre Vilotte
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Letter |
Possible control of subduction zone slow-earthquake periodicity by silica enrichment
Seismic data from subduction zones that exhibit slow earthquakes reveal that the ratio of compressional-wave to shear-wave velocity of the overriding forearc crust is linearly related to the average recurrence time of slow earthquakes and that this may be associated with quartz enrichment within the forearc crust.
- Pascal Audet
- & Roland Bürgmann
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Letter |
Uplift and seismicity driven by groundwater depletion in central California
Human-caused groundwater depletion in California’s San Joaquin Valley contributes to uplift of the surrounding mountains and may affect the stability of the San Andreas Fault.
- Colin B. Amos
- , Pascal Audet
- & Geoffrey Blewitt
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Letter |
Foundering of lower island-arc crust as an explanation for the origin of the continental Moho
The calculated density and seismic structure of the two best-exposed island arc sections (Kohistan and Talkeetna) reveals that the foundering of the lower arc crust produces a sharp seismic discontinuity characteristic of the continental Mohorovičić discontinuity.
- Oliver Jagoutz
- & Mark D. Behn
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Article |
Intra-oceanic subduction shaped the assembly of Cordilleran North America
A new explanation for the origin of the accreted terranes that form the mountainous Cordillera of western North America is proposed and tested: stationary, intra-oceanic subduction deposited massive slab walls in the mantle and grew volcanic archipelagos at the surface, which were overridden by and accreted to North America during Cretaceous times.
- Karin Sigloch
- & Mitchell G. Mihalynuk