Gravity data inversion for Moho depth modeling in the Hellenic area

Grigoriadis, Vassilios; Tziavos, I. N.; Τσοκασ, Γ. Ν.; Stampolidis, Alexandros

doi:10.1007/s00024-015-1174-y

Cited by 24 publications

(14 citation statements)

References 36 publications

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“…For both overriding and undergoing plates, four lithological/mechanical layers have been assumed, consisting of sedimentary cover, upper crust, lower crust, and upper mantle. The crustal structure, prevailing lithology, and thickness of the above layers have been retrieved mainly from regional-scale studies based on different and integrated geophysical data and methods, such as gravimetry, seismic reflection and refraction profiles, tomographic inversions based on P and S seismic waves arrival times, or receiver functions analyses (Tiberi et al, 2001, Tirel et al, 2004Zelt et al, 2005;Sodoudi et al, 2006;Makris et al, 2013;Kind et al, 2015;Grigoriadis et al, 2016;Sachpazi et al, 2016, among others). From the analysis of these studies it can be observed that the deepest Moho discontinuity occurs in the axial zone of the Hellenides fold-and-thrust belt with maximum values reaching 40-45 km of depth.…”

Section: Rheological Transects: Data and Methodsmentioning

confidence: 99%

“…Firstly, the Aegean realm presents a large spectrum of tectonic regimes (tensile, compressional, transcurrent) and examples of related active structures can be easily found and tested. Secondly, a fair amount of geological (Doutsos et al, 2006;Mountrakis, 2006) and geophysical data is available for the crustal structure (Sodoudi et al, 2006;Makris et al, 2013;Grigoriadis et al, 2016), as well as for the deformation rates (e.g., Hollenstein et al, 2008;Kreemer et al, 2014). Thirdly, the high seismicity rate that characterizes the Aegean Region allows for the recording of robust and independent seismological data (relocated earthquakes depths, focal mechanisms, spatial distribution of seismicity, etc.…”

Section: Introductionmentioning

confidence: 99%

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Rheological behaviour in continental and oceanic subduction: inferences for the seismotectonics of the Aegean Region

2020

Turkish J Earth Sci

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We reconstructed several rheological transects across the Aegean Region, comparing the behaviour in collisional versus subducting settings. We interpolated closely spaced 1D strength envelopes, realized through a dedicated MATLAB script, for determining the shallow lithospheric distribution of brittle and ductile layers. We mainly used literature data and geodynamic considerations to fix the parameters for the rheological modelling and took particular care in reproducing reliable thermal models. The results of the mechanical-rheological model highlighted the following features and differences between the northern continental collision and the southern oceanic subduction settings: i) a slightly shallower brittle-ductile transition (BDT) in the western sectors of the northern transects (~30-33 km) with respect to the southern ones (~40 km); ii) on the contrary, in the central-eastern sectors of the investigated area, corresponding to an extensional tectonic regime, the northern transects have a relatively deeper BDT (about 20-25 km) compared with the southern ones (about 15 km); iii) the occurrence of a thick, deeper brittle layer below the shallowest BDT, in the centraleastern sectors of the northern transects. We suggest that such regional differences are mainly related and attributable to the surface heat flow distribution (which directly affects the geothermal gradient) and to the tectonic and geodynamic context. The results of the rheological modelling in terms of depth extent of the brittle layer(s) have been compared with the depth distribution of available relocated seismicity, showing good agreement with the rheological layering proposed here. Finally, the depth of the shallowest BDT along the transects has been adopted as a constraint for the seismogenic layer thickness. Such information has been used to improve the seismotectonic characterization of selected crustal seismogenic sources crossing the transects, by estimating their maximum potential magnitudes on the basis of their geometrical features and consistency with the rheological layering.

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Section: Rheological Transects: Data and Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Rheological behaviour in continental and oceanic subduction: inferences for the seismotectonics of the Aegean Region

2020

Turkish J Earth Sci

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“…Gomes-Ortiz and Agarwal (2015) generalized the Parker-Oldenburg's method for a 3D gravity inversion. The Parker-Oldenburg's method has been applied in local and (small-scale) regional studies, for instance, by Rui (1985), Reamer and Ferguson (1989), Ferguson et al (1988), Tiberi et al (2001), Tirel et al (2004), Gomes-Ortiz and Agarwal (2005), Shin et al (2006Shin et al ( , 2007Shin et al ( , 2015, Chappell and Kusznir (2008), Kiamehr and Gomes-Ortiz (2009), Block et al (2009), Prutkin and Saleh (2009), Hsieh et al (2010), Steffen et al (2011), Gómez-Ortiz et al (2011), Bagherbandi (2012), Jiang et al (2012), Aitken et al (2013), Prasanna et al (2013), Meijde et al (2013Meijde et al ( , 2015, Zhang et al (2015), and Grigoriadis et al (2016). The application of this method in (large-scale) regional, continental or global studies is, however, somehow restricted by the fact that this method is formulated in the frame of the Cartesian planar topocentric coordinates, while disregarding the Earth's sphericity.…”

Section: Accepted Articlementioning

confidence: 99%

“…(2015), and Grigoriadis et al. (2016). The application of this method in (large‐scale) regional, continental, or global studies is, however, somehow restricted by the fact that this method is formulated in the frame of the Cartesian planar topocentric coordinates, while disregarding the Earth's sphericity.…”

Section: Introductionmentioning

confidence: 96%

Moho Depth Estimation Beneath Tibet From Satellite Gravity Data Based on a Condensation Approach

Chen

Tenzer

et al. 2021

Earth and Space Science

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We develop an algorithm for a Moho depth recovery from gravity and gravity gradiometry data and apply this method to estimate the Moho depth beneath the Tibetan Plateau. The basic idea of this algorithm is to describe mathematically the Moho depth undulations in terms of a condensation layer with respect to a mean Moho depth, instead of applying more commonly used isostatic compensation schemes. Expressions that functionally relate gravity field quantities with a (Moho) condensation layer are derived in spectral and spatial domains. The main advantage of this algorithm is that a functional relation between gravity field quantities and surface density anomalies, and consequently Moho depth undulations has a linear form. The proposed algorithm is tested using satellite gravity and gravity gradiometry data. The Moho depth (taken with respect to the geoid surface) estimates obtained based on applying this algorithm are validated against global and regional seismic Moho results at the study area of Tibet. We also compare the result with the corresponding Moho depth estimates obtained by applying the Parker-Oldenburg and Vening Meinesz-Moritz's (VMM) methods. The validation shows that results from all three gravimetric methods are similar, and they also closely agree with a regional seismic Moho model. Nevertheless, the VMM method and our algorithm in this comparison over-perform the Parker-Oldenburg's method. The analysis of results also reveals that the newly developed algorithm provides better result (in terms of the RMS fit with a regional seismic Moho model) when applied for a Moho determination from gravity gradiometry instead of gravity data.

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“…The latter value has been accordingly assumed as more representative for this site. The estimates of the Moho depth are provided by several authors [Sodoudi et al, 2006;Raykova and Nikolova, 2007;Makris et al, 2013;Grigoriadis et al, 2016] using different methods, like P-and S-waves receiver functions, surface waves tomography, gravity data or gravity constrained by seismic profiles. Likely due to the different methodological approaches and original datasets, they provide a quite wide range of values between ~27 to ~40 km.…”

Section: Cephalonia Areamentioning

confidence: 99%

Sensitivity analysis for crustal rheological profiles: examples from the Aegean Region

Maggini

Caputo

2020

Annals of Geophysics

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We tested the validity of rheological profiles and their sensitivity to variations in the input parameters, with particular emphasis on the resulting BDT (brittle-ductile transition) depth and corresponding strength and temperature. For this purpose, we selected two test-sites from the Aegean Region, one in an extensional tectonic setting and the other in a strike-slip regime, and carefully realized the corresponding "reference" rheological profiles based on literature data and specific geological constraints. The reference envelopes have been then compared with a set of different profiles realized by varying the input parameters of the constitutive equations of the brittle and ductile behaviours within reasonable ranges. Firstly, tests were performed by changing the value of only one input parameter per time, with the aim of quantifying and comparing its influence on the BDT properties. The parameters exerting the greatest control are the activation energy, the power-law exponent and the surface heat flow (through its influence on the geothermal gradient), for the creep behaviour. As regards the brittle behaviour parameters, the friction coefficient and the pore fluid pressure could play a significant role especially in determining the maximum strength. In a second phase, we simultaneously varied all the input parameters in order to consider the possible synergistic effects on the resulting rheological profiles and to verify the likelihood and consistency of the reference models. For the statistical approach, one hundred thousand random combinations of the analysed parameters have been generated. The particular care spent on selecting the range of values of each parameter is reflected in the results of the statistical analyses, which show a good agreement with the reference profiles and allow estimating the overall uncertainties. Finally, the obtained strength envelopes have been compared with the accurately relocated depth distribution of recent seismic sequences that affected the two test areas. In both cases, the depth corresponding to the 95% of the total released energy nicely fits the BDT depth obtained from the rheological modelling, therefore confirming that this parameter could represent a reasonable and reliable approximation of the seismogenic layer thickness.

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Gravity data inversion for Moho depth modeling in the Hellenic area

Cited by 24 publications

References 36 publications

Rheological behaviour in continental and oceanic subduction: inferences for the seismotectonics of the Aegean Region

Rheological behaviour in continental and oceanic subduction: inferences for the seismotectonics of the Aegean Region

Moho Depth Estimation Beneath Tibet From Satellite Gravity Data Based on a Condensation Approach

Sensitivity analysis for crustal rheological profiles: examples from the Aegean Region

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