ORCID Profile
0000-0001-5494-2296
Current Organisation
Australian National University
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Research Topics
In Research Link Australia (RLA), "Research Topics" refer to ANZSRC FOR and SEO codes. These topics are either sourced from ANZSRC FOR and SEO codes listed in researchers' related grants or generated by a large language model (LLM) based on their publications.
Top 5 Research Topics
ANZSRC Field of Research (FoR)
Geophysics | Seismology and Seismic Exploration | Atomic molecular and optical physics | Geophysics Not Elsewhere Classified | Nanofabrication growth and self assembly | Seismology and seismic exploration | Earthquake Seismology | Geophysics | Geotectonics | Astronomical instrumentation | Photonics optoelectronics and optical communications | Geodynamics | Nonlinear optics and spectroscopy | Tectonics
ANZSRC Socio-Economic Objective (SEO)
Expanding Knowledge in the Earth Sciences | Environmental and Natural Resource Evaluation not elsewhere classified | Copper Ore Exploration | Earth sciences |
Related Links
Publications
Introduction to the Focus Section on EarthScope Alaska and Canada
Publisher: Seismological Society of America (SSA)
Date: 23-09-2020
DOI: 10.1785/0220200307
Seismic Evidence for Thermal and Chemical Heterogeneities in D″ Region Beneath Central America From Grid Search Modeling
Publisher: American Geophysical Union (AGU)
Date: 20-07-2021
DOI: 10.1029/2021GL092493
Abstract: Large lateral variations in the depth, sharpness, and magnitude of the D″ discontinuity are observed beneath Central America and the Caribbean using a new innovative grid search modeling method. The strong correlation between the D″ topography and the underlying seismic velocities suggests a large lateral gradient in the thermal condition in the lowermost mantle. Low‐velocity patches were identified among the high‐velocity areas, coinciding with regions showing a disruption in the D″ discontinuity. The low‐velocity zones may be attributed to the heat trapped in the middle of the Farallon slab remnant while those farther to the west are likely to be associated with the upwelling generated at the edge of the ancient slab. A broad range in the sharpness of the D″ discontinuity was also observed, suggesting the existence of different chemical components in the region, as a result of a disparate mixture of basalt, harzburgite, and pyrolite.
SASSY21: A 3-D seismic structural model of the lithosphere and underlying mantle beneath Southeast Asia from multi-scale adjoint waveform tomography
Publisher: Wiley
Date: 18-08-2021
Inherited lithospheric structures control arc-continent collisional heterogeneity
Publisher: Geological Society of America
Date: 05-02-2021
DOI: 10.1130/G48246.1
Abstract: From west to east along the Sunda-Banda arc, convergence of the Indo-Australian plate transitions from subduction of oceanic lithosphere to arc-continent collision. This region of eastern Indonesia and Timor-Leste provides an opportunity for unraveling the processes that occur during collision between a continent and a volcanic arc, and it can be viewed as the temporal transition of this process along strike. We collected a range of complementary geological and geophysical data to place constraints on the geometry and history of arc-continent collision. Utilizing ∼4 yr of new broadband seismic data, we imaged the structure of the crust through the uppermost mantle. Ambient noise tomography shows velocity anomalies along strike and across the arc that are attributed to the inherited structure of the incoming and colliding Australian plate. The pattern of anomalies at depth resembles the system of salients and embayments that is present offshore western Australia, which formed during rifting of east Gondwana. Previously identified changes in geochemistry of volcanics from Pb isotope anomalies from the inner arc islands correlate with newly identified velocity structures representing the underthrusted and subducted Indo-Australian plate. Reconstruction of uplift from river profiles from the outer arc islands suggests rapid uplift at the ends of the islands of Timor and western Sumba, which coincide with the edges of the volcanic-margin protrusions as inferred from the tomography. These findings suggest that the tectonic evolution of this region is defined by inherited structure of the Gondwana rifted continental margin of the incoming plate. Therefore, the initial template of plate structure controls orogenesis.
Erosion of the continental lithosphere at the cusps of the Calabrian arc: Evidence fromSreceiver functions analysis
Publisher: American Geophysical Union (AGU)
Date: 12-2011
DOI: 10.1029/2011GL049455
Supplemental Material: Inherited lithospheric structures control arc-continent collisional heterogeneity
Publisher: Geological Society of America
Date: 15-01-2021
Abstract: Description of the methodology. br
The structural evolution of the deep continental lithosphere
Publisher: Elsevier BV
Date: 2017
Establishing earthquake monitoring in Timor–Leste
Publisher: Society of Exploration Geophysicists
Date: 17-08-2017
Southwest Australia Seismic Network (SWAN): Recording Earthquakes in Australia’s Most Active Seismic Zone
Publisher: Seismological Society of America (SSA)
Date: 18-01-2023
DOI: 10.1785/0220220323
Abstract: The geological structure of southwest Australia comprises a rich, complex record of Precambrian cratonization and Phanerozoic continental breakup. Despite the stable continental cratonic geologic history, over the past five decades the southwest of Western Australia has been the most seismically active region in continental Australia, though the reason for this activity is not yet well understood. The Southwest Australia Seismic Network (SWAN) is a temporary broadband network of 27 stations that was designed to both record local earthquakes for seismic hazard applications and provide the opportunity to dramatically improve the rendering of 3D seismic structure in the crust and mantle lithosphere. Such seismic data are essential for better characterization of the location, depth, and attenuation of the regional earthquakes, and hence understanding of earthquake hazard. During the deployment of these 27 broadband instruments, a significant earthquake swarm occurred that included three earthquakes of local magnitude 4.0 and larger, and the network was supplemented by an additional six short-term nodal seismometers at 10 separate sites in early 2022, as a rapid deployment to monitor this swarm activity. The SWAN experiment has been continuously recording since late 2020 and will continue into 2023. These data are archived at the International Federation of Digital Seismograph Networks (FDSN) - recognized Australian Passive Seismic (AusPass) Data center under network code 2P and will be publicly available in 2025.
Collisional Processes and Links to Episodic Changes in Subduction Zones
Publisher: Mineralogical Society of America
Date: 31-03-2015
Constraints on the tectonic evolution of the westernmost Mediterranean and northwestern Africa from shear wave splitting analysis
Publisher: Elsevier BV
Date: 08-2013
Breaking the slab
Publisher: Springer Science and Business Media LLC
Date: 11-2008
DOI: 10.1038/NGEO341
Aspherical structural heterogeneity within the uppermost inner core: Insights into the hemispherical boundaries and core formation
Publisher: Elsevier BV
Date: 10-2013
Melting under the Colorado Plateau, USA
Publisher: Geological Society of America
Date: 05-2012
DOI: 10.1130/G32619.1
Intermediate-Depth Earthquakes Controlled by Incoming Plate Hydration Along Bending-Related Faults
Publisher: American Geophysical Union (AGU)
Date: 04-04-2019
DOI: 10.1029/2018GL081585
Major disruption of D″ beneath Alaska
Publisher: American Geophysical Union (AGU)
Date: 05-2016
DOI: 10.1002/2015JB012534
Co-seismic deformation of deep slabs based on summed CMT data
Publisher: American Geophysical Union (AGU)
Date: 04-2012
DOI: 10.1029/2011JB008943
SASSIER22: Full-waveform tomography of the eastern Indonesian region that includes surface topography and the fluid ocean
Publisher: Wiley
Date: 08-06-2022
Upper mantle structure beneath the Caribbean‐South American plate boundary from surface wave tomography
Publisher: American Geophysical Union (AGU)
Date: 2009
DOI: 10.1029/2007JB005507
Abstract: We have measured shear wave velocity structure of the crust and upper mantle of the Caribbean‐South American boundary region by analysis of fundamental mode Rayleigh waves in the 20‐ to 100‐s period band recorded at the BOLIVAR/GEODINOS stations from 2003 to 2005. The model shows lateral variations that primarily correspond to tectonic provinces and boundaries. A clear linear velocity change parallels the plate bounding dextral strike‐slip fault system along the northern coast of Venezuela, illustrating the differences between the South American continental lithosphere, the Venezuelan archipelago, and the Caribbean oceanic lithosphere. At depths up to 120 km beneath the Venezuelan Andes and the Maracaibo block, there is evidence of underthrusting of the Caribbean plate, but there is no other evidence of subduction of the Caribbean plate beneath the South American plate. In eastern Venezuela, linear crustal low velocities are associated with the fold and thrust belts whereas as higher crustal velocities are imaged in the Guayana shield lithosphere. The subducting oceanic part of the South American plate is imaged beneath the Antilles arc. The surface wave images combined with seismicity data suggest shear tearing of the oceanic lithosphere away from the buoyant continental South American plate offshore of northeastern Venezuela. The continental lithosphere south of the slab tear is bent down toward the plate boundary in response to the propagating tear in the lithosphere. We interpret a nearly vertical low‐velocity “column” west of the tear centered beneath the Cariaco Basin, with three‐dimensional asthenospheric flow around the southern edge of the subducting oceanic lithosphere, with the asthenosphere escaping from beneath continental South America and rising into the plate boundary zone. The complex plate boundary structure is best examined in three dimensions. We discuss the new surface wave tomographic inversion in the context of results from other researchers including local seismicity, teleseismic shear wave splits, and interpretations from active source profiling.
High frequency seismic waves and slab structures beneath Italy
Publisher: Elsevier BV
Date: 04-2014
Continent–arc collision in the Banda Arc imaged by ambient noise tomography
Publisher: Elsevier BV
Date: 09-2016
Evolutionary aspects of lithosphere discontinuity structure in the western U.S.
Publisher: American Geophysical Union (AGU)
Date: 07-2012
DOI: 10.1029/2012GC004056
Tectonic inheritance during plate boundary evolution in southern California constrained from seismic anisotropy
Publisher: Wiley
Date: 19-08-2021
Segmentation and Radial Anisotropy of the Deep Crustal Magmatic System Beneath the Cascades Arc
Publisher: American Geophysical Union (AGU)
Date: 03-2023
DOI: 10.1029/2022GC010738
Abstract: Volcanic arcs consist of many distinct vents that are ultimately fueled by the common melting processes in the subduction zone mantle wedge. Seismic imaging of crustal‐scale magmatic systems can provide insight into how melt is organized in the deep crust and eventually focused beneath distinct vents as it ascends and evolves. Here, we investigate the crustal‐scale structure beneath a section of the Cascades arc spanning four major stratovolcanoes: Mt. Hood, Mt. St. Helens (MSH), Mt. Adams (MA), and Mt. Rainier, based on ambient noise data from 234 seismographs. Simultaneous inversion of Rayleigh and Love wave dispersion constrains the isotropic shear velocity ( Vs ) and identifies radially anisotropic structures. Isotropic Vs shows two sub‐parallel low‐ Vs zones (∼3.45–3.55 km/s) at ∼15–30 km depth with one connecting Mt. Rainier to MA, and another connecting MSH to Mt. Hood, which are interpreted as deep crustal magma reservoirs containing up to ∼2.5%–6% melt, assuming near‐equilibrium melt geometry. Negative radial anisotropy, from vertical fractures like dikes, is prevalent in this part of the Cascadia, but is interrupted by positive radial anisotropy, from subhorizontal features like sills, extending vertically beneath MA and Mt. Rainier at ∼10–30 km depth and weaker and west‐dipping positive anisotropy beneath MSH. The positive anisotropy regions are adjacent to rather than co‐located with the isotropic low‐ Vs anomalies. Ascending melt that stalled and mostly crystallized in sills with possible compositional differences from the country rock may explain the near‐average Vs and positive radial anisotropy adjacent to the active deep crustal magma reservoirs.
Multiscale crustal architecture of Alaska inferred from P receiver functions
Publisher: GeoScienceWorld
Date: 30-01-2018
DOI: 10.1130/L701.1
Subduction-driven recycling of continental margin lithosphere
Publisher: Springer Science and Business Media LLC
Date: 11-2014
DOI: 10.1038/NATURE13878
Abstract: Whereas subduction recycling of oceanic lithosphere is one of the central themes of plate tectonics, the recycling of continental lithosphere appears to be far more complicated and less well understood. Delamination and convective downwelling are two widely recognized processes invoked to explain the removal of lithospheric mantle under or adjacent to orogenic belts. Here we relate oceanic plate subduction to removal of adjacent continental lithosphere in certain plate tectonic settings. We have developed teleseismic body wave images from dense broadband seismic experiments that show higher than expected volumes of anomalously fast mantle associated with the subducted Atlantic slab under northeastern South America and the Alboran slab beneath the Gibraltar arc region the anomalies are under, and are aligned with, the continental margins at depths greater than 200 kilometres. Rayleigh wave analysis finds that the lithospheric mantle under the continental margins is significantly thinner than expected, and that thin lithosphere extends from the orogens adjacent to the subduction zones inland to the edges of nearby cratonic cores. Taking these data together, here we describe a process that can lead to the loss of continental lithosphere adjacent to a subduction zone. Subducting oceanic plates can viscously entrain and remove the bottom of the continental thermal boundary layer lithosphere from adjacent continental margins. This drives surface tectonics and pre-conditions the margins for further deformation by creating topography along the lithosphere-asthenosphere boundary. This can lead to development of secondary downwellings under the continental interior, probably under both South America and the Gibraltar arc, and to delamination of the entire lithospheric mantle, as around the Gibraltar arc. This process reconciles numerous, sometimes mutually exclusive, geodynamic models proposed to explain the complex oceanic-continental tectonics of these subduction zones.
Mapping Earth's deepest secrets
Publisher: American Association for the Advancement of Science (AAAS)
Date: 12-06-2020
Abstract: Sequencing seismograms pinpoint new structures near Earth's core-mantle boundary
Oligocene-Neogene lithospheric-scale reactivation of Mesozoic terrane accretionary structures in the Alaska Range suture zone, southern Alaska, USA
Publisher: Geological Society of America
Date: 03-08-2020
DOI: 10.1130/B35665.1
Abstract: Terrane accretion forms lithospheric-scale fault systems that commonly experience long and complex slip histories. Unraveling the evolution of these suture zone fault systems yields valuable information regarding the relative importance of various upper crustal structures and their linkage through the lithosphere. We present new bedrock geologic mapping and geochronology data documenting the geologic evolution of reactivated shortening structures and adjacent metamorphic rocks in the Alaska Range suture zone at the inboard margin of the Wrangellia composite terrane in the eastern Alaska Range, Alaska, USA. Detrital zircon uranium-lead (U-Pb) age spectra from metamorphic rocks in our study area reveal two distinct metasedimentary belts. The Maclaren schist occupies the inboard (northern) belt, which was derived from terranes along the western margin of North America during the mid- to Late Cretaceous. In contrast, the Clearwater metasediments occupy the outboard (southern) belt, which was derived from arcs built on the Wrangellia composite terrane during the Late Jurassic to Early Cretaceous. A newly discovered locality of Alaska-type zoned ultramafic bodies within the Clearwater metasediments provides an additional link to the Wrangellia composite terrane. The Maclaren and Clearwater metasedimentary belts are presently juxtaposed by the newly identified Valdez Creek fault, which is an upper crustal reactivation of the Valdez Creek shear zone, the Late Cretaceous plate boundary that initially brought them together. 40Ar/39Ar mica ages reveal independent post-collisional thermal histories of hanging wall and footwall rocks until reactivation localized on the Valdez Creek fault after ca. 32 Ma. Slip on the Valdez Creek fault expanded into a thrust system that progressed southward to the Broxson Gulch fault at the southern margin of the suture zone and eventually into the Wrangellia terrane. Detrital zircon U-Pb age spectra and clast assemblages from fault-bounded Cenozoic gravel deposits indicate that the thrust system was active during the Oligocene and into the Pliocene, likely as a far-field result of ongoing flat-slab subduction and accretion of the Yakutat microplate. The Valdez Creek fault was the primary reactivated structure in the suture zone, likely due to its linkage with the reactivated boundary zone between the Wrangellia composite terrane and North America in the lithospheric mantle.
The geophysical signatures of the West African Craton
Publisher: Elsevier BV
Date: 03-2016
Three-dimensional numerical models of the influence of a buoyant oceanic plateau on subduction zones
Publisher: Elsevier BV
Date: 03-2010
Evolution of mantle structure beneath the northwest Pacific: Evidence from seismic tomography and paleogeographic reconstructions
Publisher: American Geophysical Union (AGU)
Date: 07-2006
DOI: 10.1029/2005TC001909
Geodynamics of oceanic plateau and plume head accretion and their role in Phanerozoic orogenic systems of China
Publisher: Elsevier BV
Date: 2015
Formation of cratonic mantle keels by arc accretion: Evidence from S receiver functions
Publisher: American Geophysical Union (AGU)
Date: 09-2010
DOI: 10.1029/2010GL044366
Inflation and Asymmetric Collapse at Kīlauea Summit During the 2018 Eruption From Seismic and Infrasound Analyses
Publisher: American Geophysical Union (AGU)
Date: 10-2021
DOI: 10.1029/2021JB022139
Abstract: Characterizing the large M4.7+ seismic events during the 2018 Kīlauea eruption is important to understand the complex subsurface deformation at the Kīlauea summit. The first 12 events (May 17–May 26) are associated with long‐duration seismic signals and the remaining 50 events (May 29–August 2) are accompanied by large‐scale caldera collapses. Resolving the source location and mechanism is challenging because of the shallow source depth, significant nondouble‐couple components, and complex velocity structure. We demonstrate that combining multiple geophysical data from broadband seismometers, accelerometers, and infrasound is essential to resolve different aspects of the seismic source. Seismic moment tensor solutions using near‐field summit stations show the early events are inflationary. Infrasound data and particle motion analysis identify the source of inflation as the Halema'uma'u reservoir. For the later collapse events, two‐independent moment tensor inversions using local and global stations consistently show that asymmetric slips occur on inward‐dipping normal faults along the northwest corner of the caldera. While the source mechanism from May 29 onwards is not fully resolvable seismically using far‐field stations, infrasound records, and simulations suggest there may be inflation during the collapse. The summit events are characterized by both inflation and asymmetric slip, which are consistent with geodetic data. Based on the location of the slip and microseismicity, the caldera may have failed in a “see‐saw” manner: small continuous slips in the form of microseismicity on the southeast corner of the caldera, compensated by large slips on the northwest during the large collapse events.
The influence of the 2018 Lombok earthquake sequence, Indonesia on the unrest Rinjani volcano inferred from InSAR time-series analysis 
Publisher: Copernicus GmbH
Date: 27-03-2022
DOI: 10.5194/EGUSPHERE-EGU22-3579
Abstract: & & Rinjani volcano is a highly active volcano located on Lombok Island in eastern Indonesia which has experienced ten eruptions in the last 100 years. Between 2014 and 2020, this stratovolcano has erupted twice, on 25& sup& th& /sup& October 2015 and on 1st August 2016. Both eruptions lasted approximately two months, with activity concentrated in the volcanoes central Barujari Crater region. In 2018, four deadly (Mw 6.2 to 6.9) earthquakes struck the north coast of Lombok Island on 28& sup& th& /sup& July, 5& sup& th& /sup& August, and 19& sup& th& /sup& August, causing hundreds of fatalities and extensive damage. These earthquakes also resulted in the remobilization of ash deposits on the flanks of Rinjani volcano located on the north island as landslides. Our InSAR-based finite fault rupture modelling suggests the estimated maximum fault slip of 1.4 m, 2.3 m, and 2.5 m for the three mainshocks located on southward dipping fault planes to the northwest-northeast of the Rinjani volcano occurred at depths of ~15 km, 12 km, and 32 km, respectively. Coulomb stress change modelling based on the these rupture models indicates about 1 MPa of extensional stress change at 10 to 20 km of depth around the crater region was observed, which may promote opening of the magma conduit. The short distance between the peak slip region and the volcano, as well as the stress change, raises the question of whether the earthquake sequence may have influenced the spatio-temporal deformation pattern of the Rinjani volcano.We use an InSAR time-series, consisting of 658 descending and 370 ascending Sentinal-1 interferograms to investigate the time-dependent inflation and deflation signals around the crater region generated by the 2015, 2016 eruptions and the 2018 earthquakes. We analyse the average inflation/deflation rate and the cumulative displacements in different periods between 2014 and 2020 to quantify the volcano deformation before and after the 2018 earthquake sequence. Our preliminary results reveal that the crater region has undergone rapid inflation of up to 20 mm/yr through the 2014 to 2017 period, before significantly slowing to ~10 mm/yr over the 2017 to 2018 period. During the first three months following the 2018 earthquake sequence, a noticeable deflation of the edifice was detected, followed by gentle inflation lasting until late 2020. These results imply that the influence of the 2018 earthquakes acted to reduce the pressure in the reservoir, at least temporarily. We will present results from modelling the volume change and the location of the volcano pressure source for better understanding how changes in the magma body and magma movement may have been influenced by the 2018 Lombok earthquake sequence.& &
SASSY21: A 3‐D Seismic Structural Model of the Lithosphere and Underlying Mantle Beneath Southeast Asia From Multi‐Scale Adjoint Waveform Tomography
Publisher: American Geophysical Union (AGU)
Date: 03-2022
DOI: 10.1029/2021JB022930
Abstract: We present the first continental‐scale seismic model of the lithosphere and underlying mantle beneath Southeast Asia obtained from adjoint waveform tomography (often referred to as full‐waveform inversion or FWI), using seismic data filtered at periods from 20 to 150 s. Based on ,000 hr of analyzed waveform data gathered from ∼13,000 unique source‐receiver pairs, we image isotropic P ‐wave velocity, radially anisotropic S ‐wave velocity and density via an iterative non‐linear inversion that begins from a 1‐D reference model. At each iteration, the full 3‐D wavefield is determined through an anelastic Earth, accommodating effects of topography, bathymetry and ocean load. Our data selection aims to maximize sensitivity to deep structure by accounting for body wave arrivals separately. SASSY21 , our final model after 87 iterations across seven period bands, is able to explain true‐ litude data from events and receivers not included in the inversion. The trade‐off between inversion parameters is estimated through an analysis of the Hessian‐vector product. SASSY21 reveals detailed anomalies down to the mantle transition zone, including multiple subduction zones. The most prominent feature is the (Indo‐)Australian plate descending beneath Indonesia, which is imaged as one continuous slab along the 180° curvature of the Banda Arc. The tomography confirms the existence of a hole in the slab beneath Mount Tambora and locates a high S ‐wave velocity zone beneath northern Borneo that may be associated with subduction termination in the mid‐late Miocene. A previously undiscovered feature beneath the east coast of Borneo is also revealed, which may be a signature of post‐subduction processes, delamination or underthrusting from the formation of Sulawesi.
Segmentation and radial anisotropy of the deep crustal magmatic system beneath the Cascades arc
Publisher: Wiley
Date: 19-10-2022
Imaging crustal and upper mantle structure beneath the Colorado Plateau using finite frequency Rayleigh wave tomography
Publisher: American Geophysical Union (AGU)
Date: 07-2011
DOI: 10.1029/2011GC003611
On the destructive tendencies of cratons
Publisher: Geological Society of America
Date: 07-10-2020
DOI: 10.1130/G48111.1
Abstract: We propose that subducting slabs may cause lithospheric removal by directing mantle flow along the craton margin. This process could carve and shape the cratons, leading to conditions that impact the overall (in)stability of the lithosphere. We use three-dimensional geodynamic models to investigate how subduction-driven directed flow interacts with cratonic lithosphere of differing shape, concluding that the margin shape controls both channelization of flow around the craton as well as the potential for destruction. While the simulations show that all craton shapes aid in channelization, the cratons with straight vertical margins are the most resistant to deformation, and the cratons with gradually thickening margins are less resistant to deformation. The dependence on shape could contribute to the progressive removal of cratonic lithosphere along its margin in a runaway process until a more stable vertical margin shape evolves.
Towards 3D Multiscale Adjoint Waveform Tomography of the Lithosphere and Underlying Mantle beneath Southeast Asia
Publisher: Copernicus GmbH
Date: 03-03-2021
DOI: 10.5194/EGUSPHERE-EGU21-1586
Abstract: & & Southeast Asia is one of the most complex tectonic regions on Earth. This is mainly a result of its location within the triple junction of the Australian, Eurasian and Philippine Sea plates which has created a complicated configuration of active plate tectonic boundaries. Adjoint waveform tomography is especially suitable for imaging such complex regions. By simulating the 3D wavefield, it is possible to directly compare observed and simulated seismograms, thereby taking into account both body and surface waves. The method can account for the effects of anisotropy, anelasticity, wavefront healing, interference and (de)focusing that can h er other seismological methods.& & & & To date, sparse instrument coverage in the region has contributed to a heterogeneous path coverage. In this project, we make use of publicly available data as well as our recently deployed networks of broadband seismometers on Borneo and Sulawesi. This, in addition to access to national permanent networks, provides data from over 300 stations which promises a significant improvement in data coverage around the Banda Arc, Borneo and Sulawesi. We employ a geographical weighting scheme to minimise the effect of dense regional arrays and compile a catalogue of 118& well-constrained earthquakes, optimising for coverage, signal-to-noise ratio and data availability. An optimised window selection algorithm allows us to balance litude differences and include as much signal as possible while avoiding noisy data.& & & & Here, we present a seismic waveform tomography for upper mantle structure in Southeast Asia, imaging radially anisotropic S velocity, P velocity and density. We use a gradient-based optimisation scheme (L-BFGS) and adjoint methods to obtain sensitivity kernels as the corresponding gradients.& In the first part of the inversion, periods down to 50 s are used to update a 1D initial model, adapting a multi-scale approach in which long periods are inverted for first to avoid cycle skipping.& In our long-period results, we observe a strong& regional low S-velocity structure with an underlying high-velocity anomaly. The& results& are& consistent with the global& & em& S40RTS& /em& model.& & &
The impact of the 2018 Lombok earthquake sequence, Indonesia on the unrest Rinjani-Samalas volcanic complex inferred from the time-dependent seismic and volcanic source models
Publisher: Copernicus GmbH
Date: 15-05-2023
DOI: 10.5194/EGUSPHERE-EGU23-13534
Abstract: In 2018, four deadly (Mw 6.2 to 6.9) earthquakes struck the north coast of Lombok Island, on 28 July, 5August, and 19 August, distributed between the Flores back-arc thrust and the Rinjani-Samalas volcanic complex, causing hundreds of fatalities and extensive damage. We performed a comprehensive analysis of relocated aftershocks, static coulomb stress changes, and co-seismic and post-seismic deformation, to improve our understanding of this earthquake sequence. The fault geometries and slip distributions of the three mainshocks are modelled by inverting the co-seismic deformation imaged using an interferometric analysis of Sentinel-1 synthetic aperture radar (InSAR) measurements, based on rectangular dislocations embedded in a multi-layered elastic half-space. The earthquake sequence aftershocks were analysed using an unsupervised learning method (ST-DBSCAN) to cluster these relocated aftershocks so that we can identify the source of each aftershock. We used a time-series consisting of 658 descending and 370 ascending Sentinal-1 InSAR interferograms to investigate the time-dependent post-seismic deformation in the two years following the Lombok 2018 earthquake sequence, deriving a combined model that simulates the viscoelastic relaxation and afterslip simultaneously. The Coulomb stress change modelling based on the co-seismic and post-seismic rupture models indicates about 1 MPa of extensional stress change at 10 to 20 km of depth and 0.5 Mpa extensional stress change at 15 to 25 km of depth around the Barujari Crater region, respectively, which affects the open of the magma conduct, reflected as caldera-scale deflation and inflation. To quantify the influence of the earthquake sequence on the spatiotemporal deformation pattern of the volcano edifice, we extended our InSAR time-series range forward to the year 2014, just prior to the two eruptions that occurred on 25th October 2015 and 1st August 2016, and perform Principal Component Analysis to investigate the time-dependent inflation and deflation signals. We modelled the volume change and the location of the volcano pressure source for a better understanding of how changes in the magma body and magma movement may have been influenced by the 2018 Lombok earthquake sequence. A double-source compound model is used to invert the parameters of the magma chamber, including a shallow Moji point pressure source centred at 1.3 km north of the Barujari cone, and a deep source centred at 1.5 km northeast of the Rinjani cone, at ~3.9 km and ~3.5 km depth below the sea level respectively. We also used a uniform sill and dike combined model to interpret the co-eruptive signals surrounding the observed eruptive fissures. Our best-fit dike is nearly vertical, reaching a depth of 2 km below sea level with an opening of 8.5 cm, and the sill is at the depth of 3.1 km with a contraction of 40 cm.
Continuing Colorado plateau uplift by delamination-style convective lithospheric downwelling
Publisher: Springer Science and Business Media LLC
Date: 04-2011
DOI: 10.1038/NATURE10001
Abstract: The Colorado plateau is a large, tectonically intact, physiographic province in the southwestern North American Cordillera that stands at ∼1,800-2,000 m elevation and has long been thought to be in isostatic equilibrium. The origin of these high elevations is unclear because unlike the surrounding provinces, which have undergone significant Cretaceous-Palaeogene compressional deformation followed by Neogene extensional deformation, the Colorado plateau is largely internally undeformed. Here we combine new seismic tomography and receiver function images to resolve a vertical high-seismic-velocity anomaly beneath the west-central plateau that extends more than 200 km in depth. The upper surface of this anomaly is seismically defined by a dipping interface extending from the lower crust to depths of 70-90 km. The base of the continental crust above the anomaly has a similar shape, with an elevated Moho. We interpret these seismic structures as a continuing regional, delamination-style foundering of lower crust and continental lithosphere. This implies that Pliocene (2.6-5.3 Myr ago) uplift of the plateau and the magmatism on its margins are intimately tied to continuing deep lithospheric processes. Petrologic and geochemical observations indicate that late Cretaceous-Palaeogene (∼90-40 Myr ago) low-angle subduction hydrated and probably weakened much of the Proterozoic tectospheric mantle beneath the Colorado plateau. We suggest that mid-Cenozoic (∼35-25 Myr ago) to Recent magmatic infiltration subsequently imparted negative compositional buoyancy to the base and sides of the Colorado plateau upper mantle, triggering downwelling. The patterns of magmatic activity suggest that previous such events have progressively removed the Colorado plateau lithosphere inward from its margins, and have driven uplift. Using Grand Canyon incision rates and Pliocene basaltic volcanism patterns, we suggest that this particular event has been active over the past ∼6 Myr.
New Insights Into Crustal Deformation of the Indonesia–Australia–New Guinea Collision Zone From a Broad‐Scale Kinematic Model
Publisher: American Geophysical Union (AGU)
Date: 02-2023
DOI: 10.1029/2022JB024810
Abstract: The Indonesia‐Australia‐New Guinea collision zone comprises a complex system of tectonic blocks whose relative motion accommodates convergence of the Sunda Block, Pacific, Australian, and Philippine Sea plates. Previous studies have considered either the western or eastern ends of this system, in eastern Indonesia and Papua New Guinea, respectively. However, these studies had limited ability to characterize either the kinematics of the central part of the system or transitions in tectonic regime across it. In this study, we perform a simultaneous inversion of 492 earthquake slip vectors and 267 GPS velocities to quantify the block movement spanning the Sunda‐Banda Arc, Western New Guinea, and Papua New Guinea. Our best‐fitting kinematic block model comprises 23 elastic blocks, for which we estimate the rotation rates and block boundary slip rates. We show how the Cenderawasih Bay sphenochasm was likely formed by a combination of both rotations (2.82 ± 0.11°/Myr anticlockwise) of the Bird's Head Block and southwest‐directed convergence (39.9 ± 1.7 mm/yr) along the Lowlands fault. Our estimated relative slip vectors across the New Guinea Fold‐and‐Thrust Belt indicate a transition in the tectonic regime of the block boundary from predominately thrust faulting at its western segment, with a convergence rate up to 19.5 ± 0.6 mm/yr, to predominately sinistral motion in the center segment with slip rate ∼7 mm/yr, and returning to thrust in the eastern segment with a convergence rate up to 9.0 ± 0.5 mm/yr, implying the combined effect of multiple driving mechanisms.
Study of the western edge of the African Large Low Shear Velocity Province
Publisher: American Geophysical Union (AGU)
Date: 08-2013
DOI: 10.1002/GGGE.20185
Mantle Flow Deflected by Arc–Continent Collision and Continental Subduction in Eastern Indonesia
Publisher: Seismological Society of America (SSA)
Date: 23-03-2022
DOI: 10.1785/0220210281
Abstract: We investigate seismic anisotropy across southeastern Indonesia where the Indo-Australian plate subducts beneath and collides with the Sunda-Banda arc. Geochemical, geodetic, and tomographic studies reveal an along-strike transition from oceanic subduction to continental subduction and collision near central Flores that is due to a change of lithospheric composition in the subducting plate. To investigate the anisotropic fabric and dynamics of the upper mantle surrounding this young (∼5 Ma) arc–continent collision, we perform shear wave splitting analysis on local and teleseismic S waves recorded by an array of broadband seismometers that crosses the subduction–collision boundary. Seismic anisotropy inferred from our local S dataset shows that anisotropic sources above the slab extend to depths exceeding 100 km. Analysis of teleseismic SKS and SKKS waves reveal a shift in subslab fast axes from trench-parallel to trench-perpendicular near the ocean–continent boundary in the lower plate, which we relate to regional subslab mantle flow being deflected around the subducted continental lithosphere. Along-strike variations in anisotropic fast axes from teleseismic phases overlap with distinct structural and tectonic boundaries that ide distinct regions of the collision, implying the effects of the collision transcend any one dataset and highlighting the complexity of collisional boundaries. These results shed light on the interaction between tectonic structure and mantle dynamics in an emergent collision, and help constrain the nature of upper mantle deformation in the early stages of collision.
Introduction to “Orogenic Cycles: From Field Observations to Global Geodynamics”
Publisher: American Geophysical Union (AGU)
Date: 2019
DOI: 10.1029/2018TC005376
Hypocenter, Fault Plane, and Rupture Characterization of Australian Earthquakes: Application to the September 2021 Mw 5.9 Woods Point Earthquake
Publisher: Seismological Society of America (SSA)
Date: 16-03-2023
DOI: 10.1785/0220220348
Abstract: The Australian Seismometers in Schools (AuSIS) network operates 50 broadband seismic stations across Australia that are hosted at schools. The instruments augment the Australian National Seismograph Network providing valuable data from urban and regional Australia. The network coverage is quite sparse, but these vital records of rare, moderate Australian earthquakes can improve our understanding of the deformation within the stable continental region of Australia, especially for events with no surface rupture. In this study, we present the feasibility of identifying the fault plane of moderate earthquakes on the Australian continent, using data from the AuSIS network. We examine the fault plane of the September 2021 Mw 5.9 Woods Point earthquake that occurred about 130 km northeast of the Melbourne metropolitan area. We estimate the hypocenter and the centroid moment tensor (CMT) to identify the fault plane from the auxiliary plane in the focal mechanism. We explore a range of 1D models and a 3D Earth model to simulate seismic arrivals and full waveform data. The hypocenter is resolved using P- and S-wave arrivals in a probabilistic framework and the CMT is derived from full waveform modeling through grid search over a set of trial points around the hypocenter. Our solution suggests the mainshock ruptured the depth of 15 ± 4 km, with a strike-slip mechanism striking 348° north on a nearly vertical plane. The high double-couple percentage of this event indicates a simple rupture that propagated from the south (hypocenter) toward the north (centroid) and remained subsurface. This indicates that the causative fault had a deeper structure than the previously known shallow, northwest–southeast-striking faults of the region. The P and T axes deduced from our fault model are notably aligned with the maximum horizontal crustal stress in the region.
Mapping the Alaskan Moho
Publisher: Seismological Society of America (SSA)
Date: 10-10-2018
DOI: 10.1785/0220180222
Updates to FuncLab, a Matlab based GUI for handling receiver functions
Publisher: Elsevier BV
Date: 02-2018
SASSIER22: Full‐Waveform Tomography of the Eastern Indonesian Region That Includes Topography, Bathymetry, and the Fluid Ocean
Publisher: American Geophysical Union (AGU)
Date: 28-10-2022
DOI: 10.1029/2022GC010563
Abstract: We present a new 3‐D seismic structural model of the eastern Indonesian region and its surroundings from full‐waveform inversion (FWI) that exploits seismic data filtered at periods between 15–150 s. SASSY21 —a recent 3‐D FWI tomographic model of Southeast Asia—is used as a starting model, and our study region is characterized by particularly good data coverage, which facilitates a more refined image. We use the spectral‐element solver Salvus to determine the full 3‐D wavefield, accounting for the fluid ocean explicitly by solving a coupled system of acoustic and elastic wave equations. This is computationally more expensive but allows seismic waves within the water layer to be simulated, which becomes important for periods ≤20 s. We investigate path‐dependent effects of surface elevation (topography and bathymetry) and the fluid ocean on synthetic waveforms, and compare our final model to the tomographic result obtained with the frequently used ocean loading approximation. Furthermore, we highlight some of the key features of our final model— SASSIER22 —after 34 L‐BFGS iterations, which reveals detailed anomalies down to the mantle transition zone, including a convergent double‐subduction zone along the southern segment of the Philippine Trench, which was not evident in the starting model. A more detailed illumination of the slab beneath the North Sulawesi Trench reveals a pronounced positive wavespeed anomaly down to 200 km depth, consistent with the maximum depth of seismicity, and a more diffuse but aseismic positive wavespeed anomaly that continues to the 410 km discontinuity.
Heterogeneity within the subducting Pacific slab beneath the Izu–Bonin–Mariana arc: Evidence from tomography using 3D ray tracing inversion techniques
Publisher: Elsevier BV
Date: 30-06-2005
Chapter 7 Seismic interpretation and processing applications
Publisher: Elsevier
Date: 2001
Imaging changes in morphology, geometry, and physical properties of the subducting Pacific plate along the Izu–Bonin–Mariana arc
Publisher: Elsevier BV
Date: 08-2004
Seismic imaging the D″ region beneath the Central Atlantic
Publisher: Elsevier BV
Date: 07-2019
Static and dynamic support of western United States topography
Publisher: Elsevier BV
Date: 09-2014
Possible chemical modification of oceanic lithosphere by hotspot magmatism: Seismic evidence from the junction of Ninetyeast Ridge and the Sumatra–Andaman arc
Publisher: Elsevier BV
Date: 2008
Lithospheric discontinuity structure in Alaska, thickness variations determined bySpreceiver functions
Publisher: American Geophysical Union (AGU)
Date: 04-2015
DOI: 10.1002/2014TC003669
Banda Arc Experiment—Transitions in the Banda Arc‐Australian Continental Collision
Publisher: Seismological Society of America (SSA)
Date: 07-09-2016
DOI: 10.1785/0220160124
Tectonic Inheritance During Plate Boundary Evolution in Southern California Constrained From Seismic Anisotropy
Publisher: American Geophysical Union (AGU)
Date: 11-2021
DOI: 10.1029/2021GC010099
Abstract: The style of convective force transmission to plates and strain‐localization within and underneath plate boundaries remain debated. To address some of the related issues, we analyze a range of deformation indicators in southern California from the surface to the asthenosphere. Present‐day surface strain rates can be inferred from geodesy. At seismogenic crustal depths, stress can be inferred from focal mechanisms and splitting of shear waves from local earthquakes via crack‐dependent seismic velocities. At greater depths, constraints on rock fabrics are obtained from receiver function anisotropy, P n and P tomography, surface wave tomography, and splitting of SKS and other teleseismic core phases. We construct a synthesis of deformation‐related observations focusing on quantitative comparisons of deformation style. We find consistency with roughly N‐S compression and E‐W extension near the surface and in the asthenospheric mantle. However, all lithospheric anisotropy indicators show deviations from this pattern. P n fast axes and dipping foliations from receiver functions are fault‐parallel with no localization to fault traces and match post‐Farallon block rotations in the Western Transverse Ranges. Local shear wave splitting orientations deviate from the stress orientations inferred from focal mechanisms in significant portions of the area. We interpret these observations as an indication that lithospheric fabric, developed during Farallon subduction and subsequent extension, has not been completely reset by present‐day transform motion and may influence the current deformation behavior. This provides a new perspective on the timescales of deformation memory and lithosphere‐asthenosphere interactions.
Active Seismicity in the Flinders Ranges
Publisher: Virtual Explorer Pty Ltd.
Date: 2005
Inflation and Asymmetric Collapse at Kilauea Summit during the 2018 Eruption from Seismic and Infrasound Analyses
Publisher: Wiley
Date: 30-03-2021
Inflation and Asymmetric Collapse at Kīlauea Summit during the 2018 Eruption from Seismic and Infrasound Analyses
Publisher: Wiley
Date: 02-08-2021
Ocean break-up and related mountain rise controlled by a continentalcrustal root
Publisher: Copernicus GmbH
Date: 27-03-2022
DOI: 10.5194/EGUSPHERE-EGU22-6661
Abstract: & & Large-scale topography is thought to be mainly controlled by active tectonic processes. Fennoscandia is located far from any active tectonic setting and yet includes a mountain range along its passive North Atlantic margin. Models proposed to explain the origin of these enigmatic mountains are based on glacial isostatic adjustments, delamination, long-term isostatic equilibration, and dynamic support from the mantle, yet no consensus has been reached.& & & & Here we demonstrate that Precambrian lithospheric structure of Fennoscandia controlled both Cenozoic oceanic breakup and recent mountain rise in the North Atlantic region. Fennoscandia formed by amalgamation of Proterozoic and Archean continental blocks using both S- and P-receiver functions, we discovered that the Fennoscandian lithosphere still retains the original structural heterogeneity and its western margin is composed of three distinct blocks. The southern and northern blocks have relatively thin crust (~40-45 km), while the central block has thick crust (~60 km) that most likely was formed by crustal stacking during the Proterozoic amalgamation. The boundaries of the blocks continue into the oceanic crust as two major structural zones of the North-East Atlantic, suggesting that the Fennoscandian amalgamation structures determined the geometry of the ocean opening.& We found no evidence for mountain root support or delamination in the areas of high topography that could be related to the mountain formation. Instead, our results suggest that the geometry of the observed features creates conditions favorable for edge-driven convection at the adjacent narrow margins that provides dynamic support for the mountains in Scandinavia.& &
Kinematics of slab tear faults during subduction segmentation and implications for Italian magmatism
Publisher: American Geophysical Union (AGU)
Date: 04-2008
DOI: 10.1029/2007TC002143
Unraveling an enigmatic boundary along the Sunda-Banda volcanic arc
Publisher: Elsevier BV
Date: 12-2022
Isostasy, dynamic topography, and the elevation of the Apennines of Italy
Publisher: Elsevier BV
Date: 12-2014
Imaging Canary Island hotspot material beneath the lithosphere of Morocco and southern Spain
Publisher: Elsevier BV
Date: 12-2015
Hot upwelling conduit beneath the Atlas Mountains, Morocco
Publisher: American Geophysical Union (AGU)
Date: 24-11-2014
DOI: 10.1002/2014GL061884
Structure beneath the Alboran from geodynamic flow models and seismic anisotropy
Publisher: American Geophysical Union (AGU)
Date: 08-2013
DOI: 10.1002/JGRB.50309
Reactivated lithospheric-scale discontinuities localize dynamic uplift of the Moroccan Atlas Mountains: REPLY
Publisher: Geological Society of America
Date: 06-2014
DOI: 10.1130/G35715Y.1
Evidence of an upper mantle seismic anomaly opposing the Cocos slab beneath the Isthmus of Tehuantepec, Mexico
Publisher: American Geophysical Union (AGU)
Date: 07-2014
DOI: 10.1002/2014GC005320
Mantle flow at the highly arcuate northeast corner of the Lesser Antilles subduction zone: Constraints from shear-wave splitting analyses
Publisher: GeoScienceWorld
Date: 09-06-2015
DOI: 10.1130/L440.1
Small-scale heterogeneity in the lowermost mantle beneath Alaska and northern Pacific revealed from shear-wave triplications
Publisher: Elsevier BV
Date: 04-2021
Subducted Lithospheric Boundary Tomographically Imaged Beneath Arc‐Continent Collision in Eastern Indonesia
Publisher: American Geophysical Union (AGU)
Date: 28-07-2020
DOI: 10.1029/2019JB018854
Abstract: 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 erge. 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.
Lithospheric architecture beneath Hudson Bay
Publisher: American Geophysical Union (AGU)
Date: 07-2015
DOI: 10.1002/2015GC005845
Banda Arc Experiment—Transitions in the Banda Arc‐Australian Continental Collision
Publisher: Seismological Society of America (SSA)
Date: 07-09-2016
DOI: 10.1785/0220160124
A Detailed Earthquake Catalog for Banda Arc–Australian Plate Collision Zone Using Machine-Learning Phase Picker and an Automated Workflow
Publisher: Seismological Society of America (SSA)
Date: 2022
DOI: 10.1785/0320210041
Abstract: The tectonic setting of Timor–Leste and Eastern Indonesia comprises of a complex transition from oceanic lithosphere subduction to arc-continental collision. To better understand the deformation and convergent-zone structure of the region, we derive a new catalog of earthquake hypocenters and magnitudes from a temporary deployment of five years of continuous seismic data using an automated processing procedure. This includes a machine-learning phase picker, EQTransformer, and a sequential earthquake association and location workflow. We detect and locate ∼19,000 events during 2014–2018, which demonstrates that it is possible to characterize earthquake sequences from raw seismic data using a well-trained machine-learning picker for a complex convergent plate setting. This study provides the most complete catalog available for the region for the duration of the temporary deployment, which includes a complex pattern of crustal events across the collision zone and into the back-arc, as well as abundant deep slab seismicity.
Supplemental Material: Inherited lithospheric structures control arc-continent collisional heterogeneity
Publisher: Geological Society of America
Date: 15-01-2021
DOI: 10.1130/GEOL.S.13584929.V1
Abstract: Description of the methodology. br
The fate of the downgoing oceanic plate: Insight from the Northern Cascadia subduction zone
Publisher: Elsevier BV
Date: 12-2014
Opening of the north-eastern Atlantic and onshore mountain rise controlled by Fennoscandian deep structure
Publisher: Copernicus GmbH
Date: 04-03-2021
DOI: 10.5194/EGUSPHERE-EGU21-15825
Abstract: & & Large-scale topography is thought to be mainly controlled by active tectonic processes. Fennoscandia is located far from any active tectonic setting and yet includes a mountain range along its passive North Atlantic margin. Models proposed to explain the origin of these enigmatic mountains are based on glacial isostatic adjustments, delamination, long-term isostatic equilibration, and dynamic support from the mantle, yet no consensus has been reached. We show that topography along the continental margin of Fennoscandia may be influenced by its deep structure. Fennoscandia formed by amalgamation of Proterozoic and Archean continental blocks using both S- and P-receiver functions, we discovered that the Fennoscandian lithosphere still retains the original structural heterogeneity and its western margin is composed of three distinct blocks. The southern and northern blocks have relatively thin crust (~40-45 km), while the central block has thick crust (~60 km) that most likely was formed by crustal stacking during the Proterozoic amalgamation. The boundaries of the blocks continue into the oceanic crust as two major structural zones of the North-East Atlantic, suggesting that the Fennoscandian amalgamation structures determined the geometry of the ocean opening.& We found no evidence for mountain root support or delamination in the areas of high topography that could be related with mountain formation. Instead, our results suggest that both crustal and lithospheric heterogeneity of Fennoscandia along the continental margin might have a control on geodynamic forces that support the rise of Scandinavian mountains.& & &
Moho structure across the San Jacinto fault zone: Insights into strain localization at depth
Publisher: GeoScienceWorld
Date: 02-2014
DOI: 10.1130/L295.1
Insights on the upper mantle beneath the Eastern Alps
Publisher: Elsevier BV
Date: 10-2014
Morphology of the distorted subducted Pacific slab beneath the Hokkaido corner, Japan
Publisher: Elsevier BV
Date: 06-2006
Three-dimensional visualization of a near-vertical slab tear beneath the southern Mariana arc
Publisher: American Geophysical Union (AGU)
Date: 06-2006
DOI: 10.1029/2005GC001110
Flat‐slab subduction, topography, and mantle dynamics in southwestern Mexico
Publisher: American Geophysical Union (AGU)
Date: 09-2015
DOI: 10.1002/2015TC003908
Insights into the evolution of the Italian lithospheric structure from S receiver function analysis
Publisher: Elsevier BV
Date: 09-2012
Crustal Structure of Active Deformation Zones in Africa: Implications for Global Crustal Processes
Publisher: American Geophysical Union (AGU)
Date: 12-2017
DOI: 10.1002/2017TC004526
Irregular Transition Layer Beneath the Earth's Inner Core Boundary From Observations of Antipodal PKIKP and PKIIKP Waves
Publisher: American Geophysical Union (AGU)
Date: 10-2018
DOI: 10.1029/2018GC007562
Reactivated lithospheric-scale discontinuities localize dynamic uplift of the Moroccan Atlas Mountains
Publisher: Geological Society of America
Date: 22-11-2013
DOI: 10.1130/G34959.1
Craton formation: Internal structure inherited from closing of the early oceans
Publisher: GeoScienceWorld
Date: 02-2014
DOI: 10.1130/L321.1
Seismic Imaging of the Alaska Subduction Zone: Implications for Slab Geometry and Volcanism
Publisher: American Geophysical Union (AGU)
Date: 11-2018
DOI: 10.1029/2018GC007962
Correction to: Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study
Publisher: Springer Science and Business Media LLC
Date: 26-02-2021
Tomographic Imaging of Slab Segmentation and Deformation in the Greater Antilles
Publisher: American Geophysical Union (AGU)
Date: 08-2018
DOI: 10.1029/2018GC007603
Dynamics of continental accretion
Publisher: Springer Science and Business Media LLC
Date: 23-03-2014
DOI: 10.1038/NATURE13033
Abstract: Subduction zones become congested when they try to consume buoyant, exotic crust. The accretionary mountain belts (orogens) that form at these convergent plate margins have been the principal sites of lateral continental growth through Earth's history. Modern ex les of accretionary margins are the North American Cordilleras and southwest Pacific subduction zones. The geologic record contains abundant accretionary orogens, such as the Tasmanides, along the eastern margin of the supercontinent Gondwana, and the Altaïdes, which formed on the southern margin of Laurasia. In modern and ancient ex les of long-lived accretionary orogens, the overriding plate is subjected to episodes of crustal extension and back-arc basin development, often related to subduction rollback and transient episodes of orogenesis and crustal shortening, coincident with accretion of exotic crust. Here we present three-dimensional dynamic models that show how accretionary margins evolve from the initial collision, through a period of plate margin instability, to re-establishment of a stable convergent margin. The models illustrate how significant curvature of the orogenic system develops, as well as the mechanism for tectonic escape of the back-arc region. The complexity of the morphology and the evolution of the system are caused by lateral rollback of a tightly arcuate trench migrating parallel to the plate boundary and orthogonally to the convergence direction. We find geological and geophysical evidence for this process in the Tasmanides of eastern Australia, and infer that this is a recurrent and global phenomenon.
Global quieting of high-frequency seismic noise due to COVID-19 pandemic lockdown measures
Publisher: American Association for the Advancement of Science (AAAS)
Date: 11-09-2020
Abstract: Seismic background noise dramatically decreased as a result of lockdown measures in place for mitigating the spread of COVID-19.
Mantle flow deflected by interactions between subducted slabs and cratonic keels
Publisher: Springer Science and Business Media LLC
Date: 19-08-2012
DOI: 10.1038/NGEO1553
Identification and tectonic implications of a tear in the South American plate at the southern end of the Lesser Antilles
Publisher: American Geophysical Union (AGU)
Date: 11-2008
DOI: 10.1029/2008GC002084
Tectonic Fabric in the Banda Arc‐Australian Continent Collisional Zone Imaged by Teleseismic Receiver Functions
Publisher: American Geophysical Union (AGU)
Date: 27-05-2022
DOI: 10.1029/2021GC010262
Abstract: The convergent plate boundary in eastern Indonesia and Timor‐Leste captures an active oblique collision between the Banda Arc and the Australian plate. We analyzed ∼5 years' worth (2014–2019) of radial and tangential teleseismic Ps receiver functions (RFs) observed at 30 temporary broadband seismic stations across the area. Azimuthal variations in RF arrivals are observed throughout the region, indicative of the presence of oriented tectonic fabrics (dipping contrasts or plunging axis anisotropy) from a variety of crustal depths. The two main strikes of these fabrics are roughly parallel to the orogen and the plate convergence across the outer arc islands, likely associated with orogenic and strike‐slip structures. We observe distinct double polarity‐reversal arrivals with opposite polarity that reflect an anisotropic layer with orogen‐parallel strikes in the shallow crust beneath Timor and Savu, interpreted as metamorphic rocks. Fabrics oriented E‐W are imaged beneath the Flores and Lomblen that host active volcanoes, where we find interesting correlations with magmatic structures. NNW‐SSE striking fabric is imaged at ∼13 km depth beneath central Flores, which relates to a connected dike magmatic system that feeds the aligned cinder cones exposed on the surface. Finally, we identify convergence‐parallel fabrics on the volcano‐extinct islands of Alor and Atauro, consistent with one main fabric orientation imaged in Timor. We suggest all convergence‐parallel fabrics might accommodate strike‐slip motion generated by the overall NNE convergence of the Australian plate with respect to Eurasian plate and contribute to strain partitioning between the trough and backarc resulting from the collision.
Fate of Forearc Lithosphere at Arc‐Continent Collision Zones: Evidence From Local Earthquake Tomography of the Sunda‐Banda Arc Transition, Indonesia
Publisher: American Geophysical Union (AGU)
Date: 23-03-2020
DOI: 10.1029/2019GL086472
VSand density structure beneath the Colorado Plateau constrained by gravity anomalies and joint inversions of receiver function and phase velocity data
Publisher: American Geophysical Union (AGU)
Date: 02-2012
DOI: 10.1029/2011JB008522
Bulldozing the core–mantle boundary: Localized seismic scatterers beneath the Caribbean Sea
Publisher: Elsevier BV
Date: 09-2008
Seismic Imaging of the Subducted Australian Continental Margin Beneath Timor and the Banda Arc Collision Zone
Publisher: American Geophysical Union (AGU)
Date: 19-02-2021
DOI: 10.1029/2020GL089632
Abstract: Detailed crustal and uppermost mantle structure is imaged for the first time utilizing ∼4 years of broadband seismic data newly collected in the Timor‐Leste and Nusa Tenggara Timor region of Indonesia. We apply three techniques, ambient noise tomography, teleseismic P wave receiver function, and coda autocorrelation, to resolve a 3D Vs model and Moho structure. Our tomographic images show low‐velocity anomalies ( km) beneath Timor related to underthrusted Gondwana sequence from the Australian plate, which are vertically offset by the high‐velocity backstop of the Banda forearc terrane. The structure progressively changes along strike, reflecting different collisional stages developed as a result of the oblique convergence. At greater depth, we detect seismically fast lithospheric mantle ( km) and the arc‐ward dipping Moho beneath Timor, both interpreted to be from the Australian plate. Our findings provide direct structural evidence of the Australian continental margin at lithospheric depths beneath the Banda Arc collisional zone.
Seismic imaging of the Cocos plate subduction zone system in central Mexico
Publisher: American Geophysical Union (AGU)
Date: 07-2012
DOI: 10.1029/2012GC004033
Spatial and temporal evolution of the subducting Pacific plate structure along the western Pacific margin
Publisher: American Geophysical Union (AGU)
Date: 02-2006
DOI: 10.1029/2005JB003705
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