An alternative method for density variation modeling of the crust based on 3-D gravity inversion

Ardalan, Alireza A.; Zamzam, Davood; Karimi, Roohollah

doi:10.1016/j.jappgeo.2011.06.033

Cited by 2 publications

(2 citation statements)

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“…Several methodologies have been applied by different authors to obtain the residual gravity anomaly for Iran (e.g. Dehghani & Makris 1984; Snyder & Barazangi 1986; Kiamehr 2006; Ardalan et al 2011), which provided results with variations exceeding 20 mGal among them. One of the main problems in computing the residual gravity anomaly in the Zagros region is the scarcity of geophysical data to add constraints to this calculation.…”

Section: Introductionmentioning

confidence: 99%

3-D lithospheric structure and regional/residual Bouguer anomalies in the Arabia-Eurasia collision (Iran)

Jiménez‐Munt

Fernàndez

Saura

et al. 2012

Geophysical Journal International

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SUMMARY The aim of this work is to propose a first‐order estimate of the crustal and lithospheric mantle geometry of the Arabia–Eurasia collision zone and to separate the measured Bouguer anomaly into its regional and local components. The crustal and lithospheric mantle structure is calculated from the geoid height and elevation data combined with thermal analysis. Our results show that Moho depth varies from ∼42 km at the Mesopotamian–Persian Gulf foreland basin to ∼60 km below the High Zagros. The lithosphere is thicker beneath the foreland basin (∼200 km) and thinner underneath the High Zagros and Central Iran (∼140 km). Most of this lithospheric mantle thinning is accommodated under the Zagros mountain belt coinciding with the suture between two different mantle domains on the Sanandaj–Sirjan Zone. The regional gravity field is obtained by calculating the gravimetric response of the 3‐D crustal and lithospheric mantle structure obtained by combining elevation and geoid data. The calculated regional Bouguer anomaly differs noticeably from those obtained by filtering or just isostatic methods. The residual gravity anomaly, obtained by subtraction of the regional components to the measured field, is analyzed in terms of the dominating upper crustal structures. Deep basins and areas with salt deposits are characterized by negative values (∼−20 mGal), whereas the positive values are related to igneous and ophiolite complexes and shallow basement depths (∼20 mGal).

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Section: Introductionmentioning

confidence: 99%

3-D lithospheric structure and regional/residual Bouguer anomalies in the Arabia-Eurasia collision (Iran)

Jiménez‐Munt

Fernàndez

Saura

et al. 2012

Geophysical Journal International

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“…Blaschek et al (2008) used a new regularization scheme based on the Minimum Gradient Support (MGS) and active constraint balancing to invert the induced polarization data. Ardalan et al (2011) used an alternative method for density variation modeling of the crust from constrained inversion of the terrestrial gravity data. Pašteka et al (2012) used Tikhonov regularization for stable downward continuation of geophysical potential fields.…”

Section: Introductionmentioning

confidence: 99%

Solving ill-posed magnetic inverse problem using a Parameterized Trust-Region Sub-problem

Abdelazeem

2013

Contributions to Geophysics and Geodesy

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Abstract:The aim of this paper is to find a plausible and stable solution for the inverse geophysical magnetic problem. Most of the inverse problems in geophysics are considered as ill-posed ones. This is not necessarily due to complex geological situations, but it may arise because of ill-conditioned kernel matrix. To deal with such ill-conditioned matrix, one may truncate the most ill part as in truncated singular value decomposition method (TSVD). In such a method, the question will be where to truncate? In this paper, for comparison, we first try the adaptive pruning algorithm for the discrete L-curve criterion to estimate the regularization parameter for TSVD method. Linear constraints have been added to the ill-conditioned matrix. The same problem is then solved using a global optimizing and regularizing technique based on Parameterized Trust Region Sub-problem (PTRS). The criteria of such technique are to choose a trusted region of the solutions and then to find the satisfying minimum to the objective function. The ambiguity is controlled mainly by proper choosing the trust region. To overcome the natural decay in kernel with depth, a specific depth weighting function is used. A Matlab-based inversion code is implemented and tested on two synthetic total magnetic fields contaminated with different levels of noise to simulate natural fields. The results of PTRS are compared with those of TSVD with adaptive pruning L-curve. Such a comparison proves the high stability of the PTRS method in dealing with potential field problems. The capability of such technique has been further tested by applying it to real data from Saudi Arabia and Italy.

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An alternative method for density variation modeling of the crust based on 3-D gravity inversion

Cited by 2 publications

References 49 publications

3-D lithospheric structure and regional/residual Bouguer anomalies in the Arabia-Eurasia collision (Iran)

3-D lithospheric structure and regional/residual Bouguer anomalies in the Arabia-Eurasia collision (Iran)

Solving ill-posed magnetic inverse problem using a Parameterized Trust-Region Sub-problem

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