Further studies on the Fennoscandian gravity field versus the Moho depth and land uplift

Sjöberg, Lars E.; Fan, Huaan; Nord, Tomas

doi:10.1007/bf00807990

Cited by 8 publications

(8 citation statements)

References 11 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…After removing the effect of crustal thickening, the negative anomaly in the gravity field was almost completely removed [Marquart, 1989], supporting the conclusion that crustal thickening is dominant in the gravity field. A more elaborate method [Sjöberg et al, 1994] improved on this study and concluded that postglacial uplift was responsible for −28 mGal and crustal thickening for −12 mGal in the observed gravity anomaly. In a recent study, Sjöberg and Bagherbandi [2013] apply bandpass filtering to the spherical harmonic coefficients, assuming the GIA signal resides ROOT ET AL.…”

Section: Introductionmentioning

confidence: 88%

“…−30 mGal [Mitrovica and Peltier, 1989;Sjöberg et al, 1994;Sjöberg and Bagherbandi, 2013]. The spread in predicted gravity anomalies shows that the observed static gravity anomaly could be a useful constraint on GIA modelling, provided that the uncertainty from other static gravity sources can be corrected for.…”

Section: Gia Modelmentioning

confidence: 93%

“…Some studies [e.g., Sjöberg et al, 1994] have separated the GIA signal from other gravity anomaly sources by filtering the spherical harmonic series. For example, Sjöberg and Bagherbandi [2013] use the geoid signal in the spherical harmonic domain of degree and order 10-70 (12 m peak value) to constrain remaining uplift in Fennoscandia to 80 m. The idea behind this band-pass filtering of the spherical harmonic coefficients is to ROOT ET AL.…”

Section: Separating Gia Gravity Signal Using Spherical Harmonic Coeffmentioning

confidence: 99%

“…Figure 1 shows the satellite-derived free-air anomaly observed in the Fennoscandian region. The negative gravity anomaly observed in the Bay of Bothnia (for geographical references, see Figure 2) is linked to the Glacial Isostatic Adjustment (GIA) in that area [Heiskanen and Vening Meinesz, 1958;Balling, 1980;Sjöberg et al, 1994]. However, the characteristic elliptic shape of GIA is not immediately visible in the static gravity field.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Glacial isostatic adjustment in the static gravity field of Fennoscandia

et al. 2015

View full text Add to dashboard Cite

In the central part of Fennoscandia, the crust is currently rising, because of the delayed response of the viscous mantle to melting of the Late Pleistocene ice sheet. This process, called Glacial Isostatic Adjustment (GIA), causes a negative anomaly in the present-day static gravity field as isostatic equilibrium has not been reached yet. Several studies have tried to use this anomaly as a constraint on models of GIA, but the uncertainty in crustal and upper mantle structures has not been fully taken into account. Therefore, our aim is to revisit this using improved crustal models and compensation techniques. We find that in contrast with other studies, the effect of crustal anomalies on the gravity field cannot be effectively removed, because of uncertainties in the crustal and upper mantle density models. Our second aim is to estimate the effects on geophysical models, which assume isostatic equilibrium, after correcting the observed gravity field with numerical models for GIA. We show that correcting for GIA in geophysical modelling can give changes of several kilometer in the thickness of structural layers of modeled lithosphere, which is a small but significant correction. Correcting the gravity field for GIA prior to assuming isostatic equilibrium and inferring density anomalies might be relevant in other areas with ongoing postglacial rebound such as North America and the polar regions.

show abstract

Section: Introductionmentioning

confidence: 88%

Section: Gia Modelmentioning

confidence: 93%

Section: Separating Gia Gravity Signal Using Spherical Harmonic Coeffmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Glacial isostatic adjustment in the static gravity field of Fennoscandia

et al. 2015

View full text Add to dashboard Cite

show abstract

“…Discussions of the relation between the geoidal depression and the structure of the Moho were given in a series of studies, e.g. Sjöberg et al (1991, 1994), Nord (1992), and Nord & Sjöberg (1992). In these studies, an integral formulation and recent Moho maps were employed.…”

Section: Introductionmentioning

confidence: 99%

Structural effects of the crust on the geoid modelled using deep seismic sounding interpretations

Kakkuri

Wang

1998

Geophys. J. Int.

View full text Add to dashboard Cite

According to the theory of isostasy, the Earth has a tendency to deform its surface in order to reach an equilibrium state. The land‐uplift phenomenon in the area of the Fennoscandian Shield is thought to be a process of this kind. The geoid, as an equipotential surface of the Earth’s gravity field, contains information on how much the Earth’s surface departs from the equilibrium state. In order to study the isostatic process through geoidal undulations, the structural effects of the crust on the geoid have to be investigated. The structure of the crust of the Fennoscandian Shield has been extensively explored by means of deep seismic sounding (DSS). The data obtained from DSS are used to construct a 3‐D seismic‐velocity structure model of the area’s crust. The velocity model is converted to a 3‐D density model using the empirical relationship that holds between seismic velocities and crustal mass densities. Structural effects are then estimated from the 3‐D density model. The structural effects computed from the crustal model show that the mass deficiency of the crust in Fennoscandia has caused a geoidal depression twice as deep as that observed from the gravimetric geoid. It proves again that the crust has been isostatically compensated by the upper mantle. In other words, an anomalously high‐density upper mantle must exist beneath Fennoscandia.

show abstract

Gravity Inversion

Sjöberg¹,

Bagherbandi²

2017

Gravity Inversion and Integration

View full text Add to dashboard Cite

Further studies on the Fennoscandian gravity field versus the Moho depth and land uplift

Cited by 8 publications

References 11 publications

Glacial isostatic adjustment in the static gravity field of Fennoscandia

Glacial isostatic adjustment in the static gravity field of Fennoscandia

Structural effects of the crust on the geoid modelled using deep seismic sounding interpretations

Gravity Inversion

Contact Info

Product

Resources

About