Examining the suitability of the geomorphic parameters in generating the Relative Index of Active Tectonics: an example from Himalayan Frontal Thrust, India

2021 ◽  
Author(s):  
Aashna Tandon ◽  
Siddharth Prizomwala
Keyword(s):  
Spatial Variability ◽  
Active Tectonics ◽  
Active Regions ◽  
Relative Index ◽  
Himalayan Frontal Thrust ◽  
Geomorphic Parameters ◽  
Uplift Rates ◽  
Tectonically Active ◽  
Mountain Front ◽  
And Function

<p>This work emphasizes the efficient use of geomorphic parameters to form a unified index ~ Relative Index of Active Tectonics (RIAT), which has seldom been tested in areas with broader variability in the rate of deformation. This study aims to verify whether the geomorphic parameters can be used efficiently for RIAT to assess the spatial variability in deformation along the fault. The Himalayan Frontal Thrust has been chosen for morphotectonic evaluation owing to its active interplate thrust fault setting. For this purpose, we select vertical uplift sensitive geomorphic parameters viz., Mountain front sinuosity (S<sub>mf</sub>), Valley floor width-height ratio (V<sub>f</sub>), and Steepness index (K<sub>sn</sub>), as a primary tool to test the RIAT.</p><p>The result of RIAT shows the along-strike variation in response to the varying degree of deformation along the HFT. This is in fine agreement with the available long-term uplift/shortening rates and geodetic rates. Overall examination reveals RIAT being an excellent tool to assess the spatial variability in uplift rates in large tectonically active regions. However, the detailed scrutiny of individual geomorphic parameters reveals that only V<sub>f, </sub>and the K<sub>sn</sub> index are more responsive and go hand-in-hand with the RIAT variation. Whereas, S<sub>mf</sub> shows no spatial variation and function as least sensitive to such an investigation. The sensitivity of these individual parameters has implications for studies with similar settings elsewhere when quantitative rates are absent.</p>

scholarly journals TECTONIC GEOMORPHOLOGY OF ESCARPMENTS: THE CASES OF KOMPOTADES AND ΝΕΑ ANCHIALOS FAULTS

2004 ◽  
Vol 36 (4) ◽  
pp. 1716 ◽  
Author(s):  
E. Zovoili ◽  
E. Konstantinidi ◽  
I. K. Koukouvelas
Keyword(s):  
Active Tectonics ◽  
Tectonic Activity ◽  
Tectonic Geomorphology ◽  
Stream Length ◽  
Sinuosity Index ◽  
Geomorphic Indices ◽  
Tectonic Processes ◽  
Uplift Rates ◽  
Mountain Front ◽  
Active Processes

Most active processes on the surface imply that tectonics and geomorphology converge in a way that landscape change may be used as a tectonic signal, given that erosion and weathering have been taken into account. We selected two faults, the Kompotades and the Nea Anchialos faults in the Sperchios and South Thessaly rift zones respectively, and we performed a morphometric analysis. This analysis comprises geomorphic indices that have been used successfully in studies of active tectonics, as the mountain front sinuosity index (Smf), stream gradient index (SL) and valley floor width to valley height ratio (Vf). At both studied mountain fronts, the Vf index ranged between 0,4 to 1,2, implying high uplift rates, while the Smf «1 index revealed relatively high tectonic activity, which decreases towards the west. On the other hand, the SL index though more sensitive to non-tectonic processes, (i.e. the rock resistance, stream length) is less indicative of tectonic activity. Based on the distribution of the geomorphic indices a two-fault strand model is suggested forming the mountain front in the two examples with the range-ward fault strand to be more appropriate for Kompotades fault and the basinward fault strand for Nea Anchialos fault.

scholarly journals Glacial isostatic uplift of the European Alps

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Jürgen Mey ◽  
Dirk Scherler ◽  
Andrew D. Wickert ◽  
David L. Egholm ◽  
Magdala Tesauro ◽  
...  
Keyword(s):  
Ice Sheets ◽  
Active Tectonics ◽  
Active Regions ◽  
Eastern Alps ◽  
European Alps ◽  
Ice Caps ◽  
Ice Cap ◽  
Tectonically Active ◽  
Continental Ice Sheets ◽  
Rhone Valley

Abstract Following the last glacial maximum (LGM), the demise of continental ice sheets induced crustal rebound in tectonically stable regions of North America and Scandinavia that is still ongoing. Unlike the ice sheets, the Alpine ice cap developed in an orogen where the measured uplift is potentially attributed to tectonic shortening, lithospheric delamination and unloading due to deglaciation and erosion. Here we show that ∼90% of the geodetically measured rock uplift in the Alps can be explained by the Earth’s viscoelastic response to LGM deglaciation. We modelled rock uplift by reconstructing the Alpine ice cap, while accounting for postglacial erosion, sediment deposition and spatial variations in lithospheric rigidity. Clusters of excessive uplift in the Rhône Valley and in the Eastern Alps delineate regions potentially affected by mantle processes, crustal heterogeneity and active tectonics. Our study shows that even small LGM ice caps can dominate present-day rock uplift in tectonically active regions.

Islands of acetylated histone H4 in polytene chromosomes and their relationship to chromatin packaging and transcriptional activity

1990 ◽  
Vol 96 (2) ◽  
pp. 335-346
Author(s):  
B.M. Turner ◽  
L. Franchi ◽  
H. Wallace
Keyword(s):  
Polytene Chromosomes ◽  
Active Regions ◽  
Immunogold Electron Microscopy ◽  
Double Labelling ◽  
Histone H4 ◽  
Nucleosome Core ◽  
Amino Terminal ◽  
Experimental Systems ◽  
Lysine Residues ◽  
And Function

The four histones of the nucleosome core particle are all subject to enzyme-catalysed, post-translational acetylation at defined lysine residues in their amino-terminal domains. Much circumstantial evidence suggests a role for this process in modifying chromatin structure and function, but detailed mechanisms have not been defined. To facilitate studies on the functional significance of histone acetylation, we have prepared antibodies specific for the acetylated isoforms of histone H4. Because of the extreme evolutionary conservation of H4, these antisera can be applied to a wide variety of organisms and experimental systems. In the present study we have used polytene chromosomes from the salivary glands of larvae of the midge Chironomus to examine the distribution of acetylated H4 in interphase chromatin. By indirect immunofluorescence, antisera to acetylated H4 labeled the four Chironomus chromosomes with reproducible patterns of sharply defined, fluorescent bands. An antiserum to non-acetylated H4 gave a completely different, more-diffuse labelling pattern. Thus, there are defined regions, or islands, in the interphase genome that are enriched in acetylated H4. Double-labelling experiments with two antisera specific for H4 molecules acetylated at different sites, showed that each antiserum gave the same banding pattern. Immunolabelling patterns were not dependent on the pattern of phase-dense bands characteristic of these chromosomes; strongly labelled regions could correspond to phase-dense bands (i.e. condensed chromatin), to interbands or, frequently, to band-interband junctions. Immunogold electron microscopy confirmed the immunofluorescence results and showed further that regions of relatively high labelling could be either transcriptionally active or quiescent, as judged by the presence or absence of ribonucleoprotein particles. Two rapidly transcribed genes on chromosome 4 of Chironomus form characteristic ‘puffs’, the Balbiani rings BRb and BRc. The antiserum to non-acetylated H4 gave diffuse labelling throughout these puffs, demonstrating the continued presence of this histone in these transcriptionally active regions. Antisera to acetylated H4 strongly labelled the boundaries of BRb and BRc, and revealed clearly defined islands of increased H4 acetylation just within the expanded chromatin of the puffs. Labelling within the central region of each puff was much less intense. A similar pattern was observed in puffs on other chromosomes. Thus, increased H4 acetylation is not found throughout actively transcribed chromatin but occurs only at defined sites, possibly in the non-transcribed flanking regions. H4 acetylation is clearly not required for the passage of RNA polymerase through the nucleosome and we speculate that its role may be to facilitate the binding to DNA of polymerases and other proteins prior to the onset of transcription and possibly replication.

scholarly journals Origins and Function of VL30 lncRNA Packaging in Small Extracellular Vesicles: Implications for Cellular Physiology and Pathology

Biomedicines ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1742
Author(s):  
Stefania Mantziou ◽  
Georgios S. Markopoulos
Keyword(s):  
Extracellular Vesicles ◽  
Active Regions ◽  
Regulatory Elements ◽  
Binding Motif ◽  
Regulatory Sequences ◽  
Chromosomal Distribution ◽  
Non Coding Rna ◽  
Rna Biology ◽  
And Function

Long non-coding RNAs (lncRNAs) have emerged during the post-genomic era as significant epigenetic regulators. Viral-like 30 elements (VL30s) are a family of mouse retrotransposons that are transcribed into functional lncRNAs. Recent data suggest that VL30 RNAs are efficiently packaged in small extracellular vesicles (SEVs) through an SEV enrichment sequence. We analysed VL30 elements for the presence of the distinct 26 nt SEV enrichment motif and found that SEV enrichment is an inherent hallmark of the VL30 family, contained in 36 full-length elements, with a widespread chromosomal distribution. Among them, 25 elements represent active, present-day integrations and contain an abundance of regulatory sequences. Phylogenetic analysis revealed a recent spread of SEV-VL30s from 4.4 million years ago till today. Importantly, 39 elements contain an SFPQ-binding motif, associated with the transcriptional induction of oncogenes. Most SEV-VL30s reside in transcriptionally active regions, as characterised by their distribution adjacent to candidate cis-regulatory elements (cCREs). Network analysis of SEV-VL30-associated genes suggests a distinct transcriptional footprint associated with embryonal abnormalities and neoplasia. Given the established role of VL30s in oncogenesis, we conclude that their potential to spread through SEVs represents a novel mechanism for non-coding RNA biology with numerous implications for cellular homeostasis and disease.

scholarly journals Estimation of absolute stress in the hypocentral region of the 2019 Ridgecrest, California, earthquakes

2020 ◽  
Author(s):  
Yuri Fialko
Keyword(s):  
Seismic Data ◽  
Plate Tectonics ◽  
Active Faults ◽  
Active Regions ◽  
Seismogenic Zone ◽  
Shear Stresses ◽  
Strong Earthquakes ◽  
Frictional Strength ◽  
Tectonically Active ◽  
Weak Fault

Abstract Strength of the upper brittle part of the Earth's lithosphere controls deformation styles in tectonically active regions, surface topography, seismicity, and the occurrence of plate tectonics, yet it remains one of the least constrained and most debated quantities in geophysics. Seismic data (in particular, earthquake focal mechanisms) have been used to infer orientation of the principal stress axes. Here I show that the focal mechanism data can be combined with information from precise earthquake locations to place robust constraints not only on the orientation, but also on the magnitude of absolute stress at depth. The proposed method uses machine learning to identify quasi-linear clusters of seismicity associated with active faults. A distribution of the relative attitudes of conjugate faults carries information about the amplitude and spatial heterogeneity of the deviatoric stress and frictional strength in the seismogenic zone. The observed diversity of dihedral angles between conjugate faults in the Ridgecrest (California, USA) area that hosted a recent sequence of strong earthquakes suggests the effective coefficient of friction of 0.4-0.6, and depth-averaged shear stresses on the order of 25-40 MPa, intermediate between predictions of the "strong" and "weak" fault theories.

scholarly journals Moment magnitude estimates for Central Anatolian earthquakes using coda waves

2019 ◽  
Author(s):  
Tuna Eken
Keyword(s):  
Empirical Relation ◽  
Active Regions ◽  
Moment Magnitude ◽  
Central Anatolia ◽  
Coda Wave ◽  
Seismic Experiment ◽  
Tectonically Active ◽  
Passive Seismic ◽  
Passive Seismic Experiment ◽  
Good Agreement

Abstract. Proper estimate of moment magnitude that is a physical measure of the energy released at earthquake source is essential for better seismic hazard assessments in tectonically active regions. Here a coda wave modeling approach that enables the source displacement spectrum modeling of examined event was used to estimate moment magnitude of central Anatolia earthquakes. To achieve this aim, three component waveforms of local earthquakes with magnitudes 2.0 ≤ ML ≤ 5.2 recorded at 72 seismic stations which have been operated between 2013 and 2015 within the framework of the CD-CAT passive seismic experiment. An inversion on the coda wave traces of each selected single event in our database was performed in five different frequency bands between 0.75 and 12 Hz. Our resultant moment magnitudes (MW-coda) exhibit a good agreement with routinely reported local magnitude (ML) estimates for study area. Finally, we present an empirical relation between MW-coda and ML for central Anatolian earthquakes.

scholarly journals The origins and implications of paleochannels in hyperarid, tectonically active regions: The northern Atacama Desert, Chile

2020 ◽  
Vol 185 ◽  
pp. 103083 ◽  
Author(s):  
S.A. Binnie ◽  
K.R. Reicherter ◽  
P. Victor ◽  
G. González ◽  
A. Binnie ◽  
...  
Keyword(s):  
Atacama Desert ◽  
Active Regions ◽  
Tectonically Active
Sign in / Sign up

Export Citation Format

Share Document