scholarly journals Time-evolving surface and subsurface signatures of Quaternary volcanism in the Cascades arc: COMMENT

Geology ◽  
2021 ◽  
Vol 49 (7) ◽  
pp. e525-e525
Author(s):  
David R. Sherrod
Keyword(s):  
Quaternary Volcanism ◽  
Evolving Surface

scholarly journals Time-evolving surface and subsurface signatures of Quaternary volcanism in the Cascades Arc: REPLY

Geology ◽  
2021 ◽  
Vol 49 (7) ◽  
pp. e526-e526
Author(s):  
Daniel O'Hara ◽  
Leif Karlstrom ◽  
David W. Ramsey
Keyword(s):  
Quaternary Volcanism ◽  
Evolving Surface

scholarly journals Supplemental Material: Time-evolving surface and subsurface signatures of Quaternary volcanism in the Cascades Arc

2020 ◽  
Author(s):  
Daniel O'Hara ◽  
et al.
Keyword(s):  
Quaternary Volcanism ◽  
Evolving Surface

Additional description of the datasets, analyses, and results presented in this study.<br>

scholarly journals Supplemental Material: Time-evolving surface and subsurface signatures of Quaternary volcanism in the Cascades Arc

2020 ◽  
Author(s):  
Daniel O'Hara ◽  
et al.
Keyword(s):  
Quaternary Volcanism ◽  
Evolving Surface

Additional description of the datasets, analyses, and results presented in this study.<br>

Dense GPS derived deformation and rotation of intraplate blocks in Central Europe - comparison to seismicity and volcanism

2021 ◽  
Author(s):  
Zhiguo Deng ◽  
Torsten Dahm
Keyword(s):  
High Precision ◽  
Velocity Fields ◽  
Shear Stresses ◽  
Intraplate Seismicity ◽  
Strain Rates ◽  
Horizontal Shear ◽  
Regional Patterns ◽  
Quaternary Volcanism ◽  
Intraplate Deformation ◽  
Horizontal Strain

&lt;p&gt;Intraplate deformation is often small but can nowdays be resolved from high precision GNSS velocity fields derived from decade-long time series and high precision network or point wise &amp;#160;solutions if uncertainties are smaller than ~0.2 mm/a.&lt;/p&gt;&lt;p&gt;If local effects are discarded, dense velocity fields may resolve regional patterns of intraplate deformation and motion, which are related to the bending of lithospheric plates, to mantle upwelling, the diffuse or zoned deformation along structural weaknesses or faults, and the rotation of rigid blocks within a plate.&amp;#160;&lt;/p&gt;&lt;p&gt;We derive for the first time, dense high precision network solutions at 323 GNSS stations in Germany and adjacent areas and resolve regions experiencing uplift with velocities of up to ~2 mm/a, rotational relative motions with angular velocities of ~0.7&amp;#177;0.3 mas/a, and horizontal shear along an extended, &amp;#160;NS trending zone with strain rates in the range of 10-8 1/a.&amp;#160;&lt;/p&gt;&lt;p&gt;We integrate European dense velocity solutions into our dataset to discuss the geodynamic context to European microplate motions, the Alpine collision, the structure of the European mantle, Quaternary volcanism and historical seismicity.&amp;#160;&lt;/p&gt;&lt;p&gt;Unexpectedly, the zones of high horizontal strain rates only partly correlate to seismicity. Such a non-correlation between ongoing horizontal strain and seismicity has been recognized before. We discuss possible reasons for the absence of intraplate seismicity in regions experiencing recent strain, including the stress shadow effects if the strain buildup is reducing shear stresses from plate tectonics. The combination of GNSS derived dense velocity fields with time dependent seismicity models may change our current understanding of intraplate seismicity and impact the assessment of intraplate seismic hazard in future.&amp;#160;&lt;/p&gt;

Numerical evidence of persisting surface roughness when deposition stops

2022 ◽  
Vol 2022 (1) ◽  
pp. 013202
Author(s):  
Chuan Wang ◽  
Hui Xia
Keyword(s):  
Stochastic Models ◽  
Sand Dune ◽  
Angle Of Repose ◽  
Scaling Properties ◽  
Interesting Issue ◽  
Material Deposition ◽  
Evolving Surface ◽  
Qualitative Exploration ◽  
Flattening Process ◽  
Evolving Surfaces

Abstract Do evolving surfaces become flat or not with time evolving when material deposition stops? As one qualitative exploration of this interesting issue, modified stochastic models for persisting roughness have been proposed by Schwartz and Edwards (2004 Phys. Rev. E 70 061602). In this work, we perform numerical simulations on the modified versions of Edwards–Wilkinson (EW) and Kardar–Parisi–Zhang (KPZ) systems when the angle of repose is introduced. Our results show that the evolving surface always presents persisting roughness during the flattening process, and sand dune-like morphology could gradually appear, even when the angle of repose is very small. Nontrivial scaling properties and differences of evolving surfaces between the modified EW and KPZ systems are also discussed.

Focal Mechanisms of West Bohemia, Central Europe, Earthquakes—End of May 2014: Evidence of Volume Changes

2021 ◽  
Author(s):  
Dana Křížová ◽  
Jiří Málek
Keyword(s):  
Central Europe ◽  
Moment Tensor ◽  
Waveform Inversion ◽  
Low Frequency ◽  
Earthquake Swarms ◽  
Quaternary Volcanism ◽  
Moment Tensors ◽  
Isotropic Part ◽  
West Bohemia ◽  
Source Mechanisms

Abstract West Bohemia is a region with a lot of mineral springs and gas outflows, which seems to be related to the remains of Quaternary volcanism in Central Europe. Earthquake swarms in shallow depths (less than 15 km) are very frequent there. We focused on the strongest earthquake over the past 30 yr (31 May, 2014 Mw∼3.8) and on two smaller ones (Mw∼2.9 and 2.5) from the same day. Seismograms from local and regional seismic stations were used to calculate the full and deviatoric moment tensors using low-frequency full-waveform inversion. The studied events have similar source mechanisms. The aforementioned earthquake sequence was selected to observe the isotropic part (negative value = implosion) of full moment tensors. It could relate to the motion and phase transition of fluids, especially water, and CO2. The main goal of this study is to contribute to clarification of the nature of earthquake swarms in the western edge of the Bohemian Massif. Negative value of the isotropic part of full moment tensor could be related to the closing of cracks and fissures during a rupture process.

Igneous activity in central-southern Italy: Is the subduction paradigm still valid?

2022 ◽  
Author(s):  
Michele Lustrino ◽  
Claudio Chiarabba ◽  
Eugenio Carminati
Keyword(s):  
Large Scale ◽  
Oceanic Lithosphere ◽  
Tyrrhenian Sea ◽  
Calc Alkaline ◽  
Quaternary Volcanism ◽  
High K ◽  
Igneous Activity ◽  
Lateral Extent ◽  
Subduction System ◽  
Sea Area

ABSTRACT The Pliocene–Quaternary igneous record of the Tyrrhenian Sea area features a surprisingly large range of compositions from subalkaline to ultra-alkaline and from ultrabasic to acid. These rocks, emplaced within the basin and along its margins, are characterized by strongly SiO2-undersaturated and CaO-rich to strongly SiO2-oversaturated and peraluminous compositions, with sodic to ultrapotassic alkaline and tholeiitic to calc-alkaline and high-K calc-alkaline affinities. We focused on the different models proposed to explain the famous Roman Comagmatic Region, part of the Quaternary volcanism that spreads along the eastern side of the Tyrrhenian area, in the stretched part of the Apennines thrust-and-fold belt. We reviewed data and hypotheses proposed in the literature that infer active to fossil subduction up to models that exclude subduction entirely. Many field geology observations sustain the interpretation that the evolution of the Tyrrhenian-Apennine system was related to subduction of the western margin of Adria continental lithosphere after minor recycling of oceanic lithosphere. However, the lateral extent of the subducting slab in the last millions of years, when magmatism flared up, remains debatable. The igneous activity that developed in the last millions of years along the Tyrrhenian margin is here explained as originating from a subduction-modified mantle, regardless of whether the large-scale subduction system is still active.

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