scholarly journals Preliminary result for crustal properties derivation related to tectonics for hazard mitigation in Eastern Indonesia using Teleseismic P Coda

2021 ◽  
Vol 325 ◽  
pp. 01012
Author(s):  
Anang Sahroni ◽  
Leni Sophia Heliani ◽  
Cecep Pratama ◽  
Hidayat Panuntun ◽  
Wiwit Suryanto
Keyword(s):  
Cross Correlation ◽  
Receiver Functions ◽  
P Wave ◽  
Eastern Indonesia ◽  
Complex Interactions ◽  
Tectonic Processes ◽  
Resource Exploration ◽  
Crustal Origin ◽  
Different Origins ◽  
Mafic Lower Crust

Eastern Indonesia is tectonically complex, formed by different plates and microplates interactions from different origins. This complexity gives geoscientists a challenge to solve the ’jigsaw’ of the complex interactions. The understanding of tectonic processes can lead to a breakthrough in both resource exploration and disaster risk reduction. We utilize teleseismic P wave coda for random coda from scattering and deterministic coda originated from the crust-mantle boundary (Moho) to derive the crustal properties, including thickness, Vp/Vs, and qualitative scattering characteristics. For the scattering properties, we apply Iterative Cross-Correlation and Stacking (ICCS) to align the waveform. At the same time, for the crust characteristic, we employ the Receiver Functions (RF) method alongside H-k stacking. The crustal thickness recovered from the RF and H-k stacking has a good correlation with the crustal origin, where the thickness in older and stable crust originated from Sundaland and Gondwana is thicker than a younger plate of the crust arc and subduction origin. The Vp/Vs is high in a region that is interpreted to be dominated by mafic lower crust originated from oceanic-oceanic subduction during Eocene, anisotropy, or by a magmatic anomaly. The P coda also correlated well with the subsurface magmatic anomaly by providing a unique pattern.

scholarly journals No mafic layer in 80 km thick Tibetan crust

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Gaochun Wang ◽  
Hans Thybo ◽  
Irina M. Artemieva
Keyword(s):  
Seismic Data ◽  
P Wave ◽  
Indian Plate ◽  
Low Velocity ◽  
Crustal Earthquakes ◽  
Tectonic Processes ◽  
P Wave Velocity ◽  
Juvenile Crust ◽  
Mafic Lower Crust ◽  
Thick Crust

AbstractAll models of the magmatic and plate tectonic processes that create continental crust predict the presence of a mafic lower crust. Earlier proposed crustal doubling in Tibet and the Himalayas by underthrusting of the Indian plate requires the presence of a mafic layer with high seismic P-wave velocity (Vp > 7.0 km/s) above the Moho. Our new seismic data demonstrates that some of the thickest crust on Earth in the middle Lhasa Terrane has exceptionally low velocity (Vp < 6.7 km/s) throughout the whole 80 km thick crust. Observed deep crustal earthquakes throughout the crustal column and thick lithosphere from seismic tomography imply low temperature crust. Therefore, the whole crust must consist of felsic rocks as any mafic layer would have high velocity unless the temperature of the crust were high. Our results form basis for alternative models for the formation of extremely thick juvenile crust with predominantly felsic composition in continental collision zones.

Orientation of broadband seismographs in the Kashmir Himalaya: Effect on vector-based studies

2021 ◽  
Author(s):  
Ramees Mir ◽  
Imtiyaz Parvez ◽  
Vinod Gaur
Keyword(s):  
Cross Correlation ◽  
High Reliability ◽  
Receiver Functions ◽  
Fast Component ◽  
P Wave ◽  
Kashmir Himalaya ◽  
Ladakh Himalaya ◽  
Moho Depths ◽  
Data Elements ◽  
Arrival Angles

&lt;p&gt;We used regional as well as global Rayleigh wave signals (source-receiver distance: 5&amp;#176;-175&amp;#176;; M&amp;#8805; 6, Depth &amp;#8804; 150 km) recorded at 12 broadband seismic stations in northwestern Himalaya to compute arrival angles of surface waves at each station, assuming orthogonality of the horizontal components, and error-free levelling of the instrument. The average of all measurements at a station with cross-correlation values &gt; 0.8, between Hilbert transformed vertical and radial components, was interpreted as the degree of misalignment of the horizontal components in a geographic frame of reference.&lt;/p&gt;&lt;p&gt;Out of the 12 station data used in this analysis, 3 were found to have instrument misorientation errors between 5&amp;#176; and 10&amp;#176; w.r.t geographic north, 2 between 10&amp;#176; and 15&amp;#176; and the remaining 7 &lt; 5&amp;#176;. The number of measurements at each of these stations ranged from 75 to 331, with 11 stations having more than 90 measurements, assuring high reliability. We also analysed data from two nearby broadband instruments located in Ladakh Himalaya. One of these (LEH) with 46 measurements showed a misorientation error of 14.87&amp;#176;&amp;#177;4.87&amp;#176; and the other (HNL) with 48 showed an error of 0.75&amp;#176;&amp;#177;3.48&amp;#176;. Since misorientation errors based on less than 90 data elements are considered to be unstable, these were not used for further analysis.&lt;/p&gt;&lt;p&gt;We evaluated the effect of seismograph misorientations on the inverted solutions for P-wave receiver functions (RFs) and core-refracted shear waves (SKS). The errors in Moho depths and those of other intra-crustal features were within &amp;#177;2 km for instrument misorientations of up to ~15&amp;#176;, that is close to the resolution errors. But, the SKS results, notably the azimuths of the fast component, were, found to be quite sensitive to instrument misalignment. For example, a ~14&amp;#176; error in orientation was found to cause a shift of up to 20&amp;#176; in the calculated azimuth of the fast component. Corrections of misorientation errors in both cases showed reduction of variance in the inverted solutions.&lt;/p&gt;

Correlational Methods for Analysis of Dance Movements

2011 ◽  
Vol 29 (supplement) ◽  
pp. 283-304 ◽  
Author(s):  
Timothy R. Brick ◽  
Steven M. Boker
Keyword(s):  
Motion Capture ◽  
Mirror Symmetry ◽  
Cross Correlation ◽  
The Other ◽  
Free Form ◽  
Motion Capture Data ◽  
Complex Interactions ◽  
Dance Movements ◽  
Time Lagged ◽  
Insight Into

Among the qualities that distinguish dance from other types of human behavior and interaction are the creation and breaking of synchrony and symmetry. The combination of symmetry and synchrony can provide complex interactions. For example, two dancers might make very different movements, slowing each time the other sped up: a mirror symmetry of velocity. Examining patterns of synchrony and symmetry can provide insight into both the artistic nature of the dance, and the nature of the perceptions and responses of the dancers. However, such complex symmetries are often difficult to quantify. This paper presents three methods – Generalized Local Linear Approximation, Time-lagged Autocorrelation, and Windowed Cross-correlation – for the exploration of symmetry and synchrony in motion-capture data as is it applied to dance and illustrate these with examples from a study of free-form dance. Combined, these techniques provide powerful tools for the examination of the structure of symmetry and synchrony in dance.

scholarly journals Post-collisional mantle delamination in the Dinarides implied from staircases of Oligo-Miocene uplifted marine terraces

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Philipp Balling ◽  
Christoph Grützner ◽  
Bruno Tomljenović ◽  
Wim Spakman ◽  
Kamil Ustaszewski
Keyword(s):  
Balkan Peninsula ◽  
Receiver Functions ◽  
P Wave ◽  
S Wave ◽  
Slab Geometry ◽  
Surface Uplift ◽  
River Incision ◽  
Marine Terraces ◽  
Convergence System ◽  
Internal Dinarides

AbstractThe Dinarides fold-thrust belt on the Balkan Peninsula resulted from convergence between the Adriatic and Eurasian plates since Mid-Jurassic times. Under the Dinarides, S-wave receiver functions, P-wave tomographic models, and shear-wave splitting data show anomalously thin lithosphere overlying a short down-flexed slab geometry. This geometry suggests a delamination of Adriatic lithosphere. Here, we link the evolution of this continental convergence system to hitherto unreported sets of extensively uplifted Oligocene–Miocene (28–17 Ma) marine terraces preserved at elevations of up to 600 m along the Dinaric coastal range. River incision on either side of the Mediterranean-Black Sea drainage divide is comparable to the amounts of terrace uplift. The preservation of the uplifted terraces implies that the most External Dinarides did not experience substantial deformation other than surface uplift in the Neogene. These observations and the contemporaneous emplacement of igneous rocks (33–22 Ma) in the internal Dinarides suggest that the Oligo-Miocene orogen-wide uplift was driven by post-break-off delamination of the Adriatic lithospheric mantle, this was followed by isostatic readjustment of the remaining crust. Our study details how lithospheric delamination exerts an important control on crustal deformation and that its crustal signature and geomorphic imprint can be preserved for millions of years.

scholarly journals Reliable workflow for inversion of seismic receiver function and surface wave dispersion data: a “13 BB Star” case study

2019 ◽  
Vol 24 (1) ◽  
pp. 101-120
Author(s):  
Kajetan Chrapkiewicz ◽  
Monika Wilde-Piórko ◽  
Marcin Polkowski ◽  
Marek Grad
Keyword(s):  
Surface Wave ◽  
Inverse Problems ◽  
Receiver Function ◽  
Joint Inversion ◽  
Wave Dispersion ◽  
Receiver Functions ◽  
P Wave ◽  
Surface Wave Dispersion ◽  
Phase Velocity Dispersion ◽  
Wide Range

AbstractNon-linear inverse problems arising in seismology are usually addressed either by linearization or by Monte Carlo methods. Neither approach is flawless. The former needs an accurate starting model; the latter is computationally intensive. Both require careful tuning of inversion parameters. An additional challenge is posed by joint inversion of data of different sensitivities and noise levels such as receiver functions and surface wave dispersion curves. We propose a generic workflow that combines advantages of both methods by endowing the linearized approach with an ensemble of homogeneous starting models. It successfully addresses several fundamental issues inherent in a wide range of inverse problems, such as trapping by local minima, exploitation of a priori knowledge, choice of a model depth, proper weighting of data sets characterized by different uncertainties, and credibility of final models. Some of them are tackled with the aid of novel 1D checkerboard tests—an intuitive and feasible addition to the resolution matrix. We applied our workflow to study the south-western margin of the East European Craton. Rayleigh wave phase velocity dispersion and P-wave receiver function data were gathered in the passive seismic experiment “13 BB Star” (2013–2016) in the area of the crust recognized by previous borehole and refraction surveys. Final models of S-wave velocity down to 300 km depth beneath the array are characterized by proximity in the parameter space and very good data fit. The maximum value in the mantle is higher by 0.1–0.2 km/s than reported for other cratons.

scholarly journals Crustal structure beneath Tierra del Fuego, Argentina, inferred from seismic P-wave receiver functions and ambient noise autocorrelations

2019 ◽  
Vol 751 ◽  
pp. 41-53 ◽  
Author(s):  
Carolina Buffoni ◽  
Martin Schimmel ◽  
Nora Cristina Sabbione ◽  
María Laura Rosa ◽  
Gerardo Connon
Keyword(s):  
Crustal Structure ◽  
Ambient Noise ◽  
Receiver Functions ◽  
Tierra Del Fuego ◽  
P Wave

Critical Zone Observatories: Building a network to advance interdisciplinary study of Earth surface processes

2008 ◽  
Vol 72 (1) ◽  
pp. 7-10 ◽  
Author(s):  
S. P. Anderson ◽  
R. C. Bales ◽  
C. J. Duffy
Keyword(s):  
Fluid Transport ◽  
Spatial Scales ◽  
Critical Zone ◽  
Watershed Scale ◽  
Spatial And Temporal Scales ◽  
Complex Interactions ◽  
Tectonic Processes ◽  
Interdisciplinary Approaches ◽  
Dynamic Interface ◽  
Interdisciplinary Study

AbstractWe live at the dynamic interface between the solid Earth and its outer fluid envelopes. This interface, extending from the outer vegetation canopy to the base of active groundwater, was recently named the Critical Zone because it supports life and is increasingly impacted by human actions. Understanding the complex interactions between processes that operate in and shape the Critical Zone requires interdisciplinary approaches that span wide spatial and temporal scales. Tectonic processes, weathering, fluid transport, and biological processes control the function and structure of the Critical Zone. Three Critical Zone Observatories recently established by the U.S. National Science Foundation are designed to integrate studies of process interactions up to the watershed scale. A goal of the program is to build the three independently conceived observatories into a network from which broader understanding — larger spatial scales but also deeper insight — can emerge.

Sharpness of the 410-km discontinuity from the P410s and P2p410s seismic phases

2019 ◽  
Author(s):  
Lev Vinnik ◽  
Yangfan Deng ◽  
Grigoriy Kosarev ◽  
Sergey Oreshin ◽  
Zhou Zhang ◽  
...  
Keyword(s):  
Transition Zone ◽  
Southern Africa ◽  
Amplitude Ratio ◽  
Southern China ◽  
Broad Band ◽  
Receiver Functions ◽  
P Wave ◽  
Seismic Model ◽  
Yangtze Craton ◽  
Zone Water

Summary Sharpness of the 410-km boundary is of interest because it is sensitive to water content in the transition zone. We evaluate the width of the 410-km discontinuity with a new seismic method. Our estimates are inferred from the amplitude ratio of the P2p410s and P410s seismic phases that are detected in P-wave receiver functions. We applied this method to seismic recordings from arrays of broad-band stations deployed in central Fennoscandia, southern Africa and southern China. The obtained estimates of width of the 410-km discontinuity range from 10 to 22 km and always exceed the width of 7 km which is expected for anhydrous conditions. The enlarged width may be interpreted in terms of hydrous conditions, but we have found only one region (the eastern Yangtze Craton in China) where the broad 410-km discontinuity, as expected, is accompanied by a broad transition zone. Water in the transition zone may be a kind of a global phenomenon, but evidence of the enlarged width of the transition zone may be missing in most of our data because the reference seismic model is affected by water, as well.

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