Seismology

  • Article
    | Open Access

    Low-frequency earthquakes are a series of small earthquakes with lower dominant frequencies than ordinary earthquakes. By comparing the simulated earthquakes with the real data, we find that low-frequency earthquakes represent an earthquake rupture process that arrests spontaneously.

    • Xueting Wei
    • , Jiankuan Xu
    •  & Xiaofei Chen
  • Article
    | Open Access

    The 2013 Castor seismic sequence, offshore Spain, is a rare example of seismicity induced by gas storage operations. Here we show that early seismicity marked the progressive failure of a fault in response to pore pressure diffusion, while later larger earthquakes resulted by the failure of loaded asperities.

    • Simone Cesca
    • , Daniel Stich
    •  & William L. Ellsworth
  • Article
    | Open Access

    Seismic imaging of subducted plates offers a way to improve plate tectonic reconstructions. Here, Braszus et al. use new ocean-bottom seismometer data from the Lesser Antilles to locate subducted spreading centres and faults thus providing a new understanding of the evolution of the Caribbean plate.

    • Benedikt Braszus
    • , Saskia Goes
    •  & Marjorie Wilson
  • Article
    | Open Access

    Anomalously slow earthquakes play a critical role in the earthquake cycle and fault sliding. Here, the authors detect continuous seismic radiation from a glacier sliding over its bed and show persistent coastal shaking to represent an addition to the family of slow earthquakes.

    • Evgeny A. Podolskiy
    • , Yoshio Murai
    •  & Shin Sugiyama
  • Article
    | Open Access

    Models of the viscosity evolution of mantle rocks are central to analyses of postseismic deformation but constraints on underlying physical processes are lacking. Here, the authors present measurements of microscale stress heterogeneity in olivine suggesting that long-range dislocation interactions contribute to viscosity evolution.

    • David Wallis
    • , Lars N. Hansen
    •  & Ricardo A. Lebensohn
  • Article
    | Open Access

    Ordinary cracks in bulk materials feature square root singular deformation fields near their edge. Here, the authors show that rupture fronts propagating along frictional interfaces, while resembling ordinary cracks in some respects, feature edge sigularity that differs from the conventional square root one.

    • Efim A. Brener
    •  & Eran Bouchbinder
  • Article
    | Open Access

    Laboratory experiments reproducing earthquake slip in non cohesive fault rocks under fluid pressurised conditions are challenging. Thanks to these experiments, the authors show that earthquake slip occurring in tsunamigenic subduction zone faults is controlled by dilatancy and pressurisation processes.

    • S. Aretusini
    • , F. Meneghini
    •  & G. Di Toro
  • Article
    | Open Access

    The authors here study the origin of seismic Love waves induced by ocean waves. The study finds Love waves to originate along steep bathymetry and underlying geological interfaces, particularly sedimentary basins, yielding spatio-temporal information about ocean-land coupling in deep water.

    • Florian Le Pape
    • , David Craig
    •  & Christopher J. Bean
  • Article
    | Open Access

    This study shows how seismic and aseismic events are related in Mexico between 2017 and 2019. Based on a series of observations and models, the study suggests that the Mw 8.2 intraslab earthquake of 8 September 2017 severely altered the mechanical properties of the plate interface, facilitating the interaction between the events and disrupting the slow slip cycles at a regional scale.

    • V. M. Cruz-Atienza
    • , J. Tago
    •  & E. Kazachkina
  • Article
    | Open Access

    The authors locate the maximum seismic energy imprint and lateral extent of the seismic sources generated by Typhoon Ioke. Based on this data set, they present a new tool to shed light on the generation mechanism of secondary microseisms body waves.

    • Lise Retailleau
    •  & Lucia Gualtieri
  • Article
    | Open Access

    The authors here present a deep learning method to determine the source focal mechanism of earthquakes in realtime. They trained their network with approximately 800k synthetic samples and managed to successfully estimate the focal mechanism of four 2019 Ridgecrest earthquakes with magnitudes larger than Mw 5.4.

    • Wenhuan Kuang
    • , Congcong Yuan
    •  & Jie Zhang
  • Article
    | Open Access

    The authors here present geodetic and seismic data for a complete eruptive cycle (2005-2018) for Sierra Negra volcano, Galapagos Island. The data shows the largest pre-eruptive inflation (6.5 m) and rates of seismicity ever observed before a basaltic eruption and provides a rare illustration of caldera resurgence mechanisms.

    • Andrew F. Bell
    • , Peter C. La Femina
    •  & Michael J. Stock
  • Article
    | Open Access

    The authors here investigate the stiffness reduction of solid geomaterials during earthquakes via combining field, experimental and numerical data. The study shows multiple metastable contacts at small surface separations below a few diameters of a water molecule due to the oscillatory hydration interaction.

    • Su-Yang Wang
    • , Hai-Yang Zhuang
    •  & Yu Miao
  • Article
    | Open Access

    Crustal doubling in Tibet and the Himalayas by underthrusting of the Indian plate is thought to require the presence of a mafic layer above the Moho. Here, the authors present seismic data which shows that the middle Lhasa Terrane has very low velocity (Vp < 6.7 km/s) throughout the 80 km thick crust, which they suggest is predominantly felsic in composition.

    • Gaochun Wang
    • , Hans Thybo
    •  & Irina M. Artemieva
  • Review Article
    | Open Access

    This review dives deep into how earthquakes affect volcanoes, specifically into the relation between tectonic seismic activity and subsequent eruptions. Activity may increase in any volcanic setting in the 2–5 years following an earthquake, and especially at volcanic centres featuring vigorous hydrothermal activity.

    • Gilles Seropian
    • , Ben M. Kennedy
    •  & Arthur D. Jolly
  • Article
    | Open Access

    Knowledge of shear-wave anisotropy is important to understanding the structure and dynamics of the subduction zone mantle wedge. Here, the authors find unambiguous evidence that forearc anisotropy resides in the upper-plate crust, while weak anisotropy in the most seaward part of the mantle wedge indicates decoupling from the slab

    • Naoki Uchida
    • , Junichi Nakajima
    •  & Youichi Asano
  • Article
    | Open Access

    The authors show that seismogenic faults can be activated by stress perturbations by all possible modes of slip independently of the frictional properties. They demonstrate, that the nature of seismicity is mostly governed by the initial stress level along the faults.

    • François X. Passelègue
    • , Michelle Almakari
    •  & Marie Violay
  • Article
    | Open Access

    The transition from wide continental rift to continental break-up remains enigmatic. Here, the authors show that northern margin of the South China Sea records the transition between wide continental rift to a highly extended continental margin, with strikingly similar structures and metamorphic core complexes to those described from the North American Cordillera and the Aegean.

    • Hongdan Deng
    • , Jianye Ren
    •  & Pan Luo
  • Article
    | Open Access

    The origin of deep long-period earthquakes beneath active volcanoes that are sometimes considered as precursors to eruptions remains not fully understood. Here the authors show that these earthquakes can be generated by the rapid degassing in response to the slow decompression of magma over-saturated with H2O and CO2.

    • Oleg Melnik
    • , Vladimir Lyakhovsky
    •  & Olga Bergal-Kuvikas
  • Article
    | Open Access

    Regions of the subducting oceanic crust are often considered to be overpressured, owing to fluid trapped beneath an impermeable seal along the overlying inter-plate boundary. Here, the authors show that slow slip earthquakes at the Cascadia subduction zone occur immediately below a 6-10 km-thick shear zone, in which slab-derived fluids are likely trapped at near-lithostatic pore pressures.

    • Andrew J. Calvert
    • , Michael G. Bostock
    •  & Martyn J. Unsworth
  • Article
    | Open Access

    In this study, the authors investigate the predictability of sudden eruptions, motivated by the 2019 eruption at Whakaari (White Island), New Zealand. The paper proposes a machine learning approach that is able to identify eruption precursors in data streaming from a single seismic station at Whakaari.

    • D. E. Dempsey
    • , S. J. Cronin
    •  & A. W. Kempa-Liehr
  • Article
    | Open Access

    The Central Atlantic Magmatic Province is the most aerially extensive magmatic event in Earth’s history, yet few constraints exist on the volumes of intrusions at depth. Here, the authors find limited intrusive volumes beneath the South Georgia Rift, consistent with modest potential mantle temperatures (<1500 °C) related to syn-rift decompression melting.

    • R. E. Marzen
    • , D. J. Shillington
    •  & S. H. Harder
  • Article
    | Open Access

    Earth surface continues to slip after large earthquakes at a slow velocity for a period of a year or more. In this study, the authors show how such slow slip before and after large earthquakes relates to the interaction of the brittle zone of the fault with the ductile zone at greater depth.

    • Giuseppe Petrillo
    • , Eugenio Lippiello
    •  & Alberto Rosso
  • Article
    | Open Access

    Subglacial lakes and jökulhlaups (glacier outburst floods) are common in volcanic and glaciated environments, and can pose potential threats to communities living downstream. Here, the authors find that seismic tremor signals during subglacial floods can be used to locate and track the speed and size of the flood before it arrives at the river system, and improves previous methods of early glacial flood warning by a factor of 5.

    • Eva P. S. Eibl
    • , Christopher J. Bean
    •  & Kristin S. Vogfjörd
  • Article
    | Open Access

    Applying high-pressure and -temperature experiments, the authors here measure sound velocities in various liquid Fe-S alloys under conditions expected for the upper Martian core. The results together with future InSight mission data will help to understand whether the Martian core is molten Fe-S.

    • Keisuke Nishida
    • , Yuki Shibazaki
    •  & Kei Hirose
  • Article
    | Open Access

    Slow slip events are commonly observed on natural faults all around the world and are suggested to precede large magnitude and/or high frequency earthquakes. The authors here identify merging phases of slow slip events using continuous GPS measurements and define areas and periods at risk of large earthquake occurrence.

    • Quentin Bletery
    •  & Jean-Mathieu Nocquet
  • Article
    | Open Access

    The dynamics of continental subduction is largely controlled by the rheological properties of rocks involved along the subduction channel. Here, the authors reveal a prominent, yet previously undetected, low-velocity body beneath the Western Alps, along the plate interface between the European slab and the overlying Adriatic mantle, which they interpret as a serpentinite layer.

    • Liang Zhao
    • , Marco G. Malusà
    •  & Stefano Solarino
  • Article
    | Open Access

    The motions of subducted slabs are expected to drive mantle flow around slab edges, however, evidence of deep mantle flow has so far remained elusive. Here, the authors present a Full Waveform Inversion 3-D anisotropy model which allows them to infer deep subduction-induced mantle flows underneath the Mid-Americas and the Caribbean.

    • Hejun Zhu
    • , Robert J. Stern
    •  & Jidong Yang
  • Article
    | Open Access

    Indian continental subduction can explain crustal deformation, magmatic activity and uplift of the Tibetan Plateau following collision, however, the nature of the Indian subducting slab beneath Myanmar and the related tectonic regime remain unclear. Here, the authors present direct structural evidence of present-day Indian continental subduction beneath Asia.

    • Tianyu Zheng
    • , Yumei He
    •  & Myo Thant
  • Article
    | Open Access

    This study investigates deep intracontinental earthquakes. Based on field data from exhumed lower crustal pseudotachylytes and mylonites from Lofoten, northern Norway, the authors describe a novel model of earthquake nucleation in the lower crust as a transient consequence of ongoing localised aseismic creep.

    • L. R. Campbell
    • , L. Menegon
    •  & G. Pennacchioni
  • Article
    | Open Access

    Using data recorded by a new seafloor seismic network, the authors reveal the detailed 3D structure of the source zone of the great 2011 Tohoku-oki earthquake, which sheds new light on the mechanism of the great earthquake and tsunami.

    • Yuanyuan Hua
    • , Dapeng Zhao
    •  & Yixian Xu
  • Article
    | Open Access

    Decrease of friction during seismic slip is linked to temperature increase and weak phases production inside the fault core. Here the authors propose a mathematical framework which explains the frictional behaviour of all materials reported in literature and precisely captures material weakening during fault slip.

    • Hadrien Rattez
    •  & Manolis Veveakis
  • Article
    | Open Access

    Cratons represent the ancient cores of continental plates and are generally thought to have been stable since the Archean. Here however, the authors combine seismic analysis with kimberlite data to infer complete destruction of cratonic lithosphere in some places of the African continent.

    • Nicolas Luca Celli
    • , Sergei Lebedev
    •  & Carmen Gaina