Heterogeneous crust and upper mantle across the SE Brazilian Highlands and the relationship to surface deformation as inferred from magnetotelluric imaging

2008 ◽  
Vol 113 (B3) ◽  
Author(s):  
I. Figueiredo ◽  
M. A. Meju ◽  
S. L. Fontes
Keyword(s):  
Upper Mantle ◽  
Surface Deformation ◽  
Crust And Upper Mantle ◽  
The Relationship ◽  
Magnetotelluric Imaging

scholarly journals INVESTIGATION OF LITHOSPHERIC STRUCTURE IN MONGOLIA: INSIGHTS FROM INSAR OBSERVATIONS AND MODELLING

2017 ◽  
Vol XLII-2/W7 ◽  
pp. 609-616
Author(s):  
Z. Jing ◽  
F. Bihong ◽  
S. Pilong ◽  
G. Qiang
Keyword(s):  
Fault Zone ◽  
Surface Deformation ◽  
Line Of Sight ◽  
Tectonic Deformation ◽  
Deformation Pattern ◽  
Interferometric Synthetic Aperture Radar ◽  
Crust And Upper Mantle ◽  
Western Mongolia ◽  
Deformation Velocity ◽  
The Relationship

The western Mongolia is a seismically active intracontinental region, with ongoing tectonic deformation and widespread seismicity related to the far-field effects of India-Eurasia collision. During the 20th century, four earthquakes with the magnitude larger than 8 occurred in the western Mongolia and its surrounding regions, providing a unique opportunity to study the geodynamics of intracontinental tectonic deformations. The 1957 magnitude 8.3 Gobi-Altai earthquake is one of the largest seismic events. The deformation pattern of rupture zone associated with this earthquake is complex, involving left-lateral strike-slip and reverse dip-slip faulting on several distinct geological structures in a 264&amp;thinsp;×&amp;thinsp;40&amp;thinsp;km wide zone. To understand the relationship between the observed postseismic surface deformation and the rheological structure of the upper lithosphere, Interferometric Synthetic Aperture Radar (InSAR) data are used to study the 1957 earthquake. Then we developed a postseismic model in a spherical, radially layered elastic-viscoelastic Earth based on InSAR results, and further analysed the dominant contribution to the surface deformation. This work is important for understanding not only the regional tectonics, but also the structure and dynamics of the lithosphere. <br><br> SAR data were acquired from the ERS1/2 and Envisat from 1996 to 2010. Using the Repeat Orbit Interferometry Package (ROI_PAC), 124 postseismic interferograms are produced on four adjacent tracks. By stacking these interferograms, the maximum InSAR line-of-sight deformation rate along the Gobi-Altai fault zone is obtained. The main results are as follows: (1) The maximum InSAR line-of-sight deformation velocity along this large fault zone is about 6&amp;thinsp;mm/yr; (2) The modelled surface deformation suggests that the viscoelastic relaxation is the most reasonable mechanism to explain the observed surface motion; (3) The optimal model cover the Gobi-Altai seismogenic thickness is 10&amp;thinsp;km; (4) The lower bound of Maxwell viscosity of lower crust and upper mantle is approximately 9&amp;thinsp;×&amp;thinsp;10<sup>19</sup>&amp;thinsp;Pa&amp;thinsp;s, and the Maxwell relaxation time corresponding to this viscosity is 95.13 years.

Earthquake energy release and isostasy

1964 ◽  
Vol 54 (2) ◽  
pp. 777-784
Author(s):  
Joseph W. Berg ◽  
Robert Gaskell ◽  
Verrill Rinehart
Keyword(s):  
United States ◽  
Energy Release ◽  
Upper Mantle ◽  
West Indies ◽  
Averaging Method ◽  
The United States ◽  
Crust And Upper Mantle ◽  
Earthquake Energy ◽  
East Indies ◽  
The Relationship

ABSTRACT The relationship between isostatic anomalies and average annual earthquake energy released was investigated. Data were used for the United States, West Indies, East Indies, Japan, Africa, and India. The above areas were subdivided into smaller areas, 5° on the side, and the data for the smaller areas were used to determine a relationship between the variables. Because the data were considerably scattered, an averaging method was used for smoothing. Results of the research indicate that (1) a relationship exists between the average annual earthquake energy released from regions and the isostatic relief (or gradient) of the regions, and (2) the isostatic relief can be used as an index of the strain level of the crust and upper mantle.

LASA anomalies and their relations to crust and upper-mantle structure

1970 ◽  
Author(s):  
H.M. Iyer ◽  
A.R. Jackson ◽  
J.H. Healy ◽  
T.E. Landers
Keyword(s):  
Upper Mantle ◽  
Mantle Structure ◽  
Crust And Upper Mantle ◽  
Upper Mantle Structure

THE CRUST AND UPPER MANTLE STRUCTURES IN CENTRAL ANATOLIA, TURKEY, CONSTRAINED BY GRAVITY AND SEISMIC DATA

2020 ◽  
Author(s):  
Yagmur Yilmaz ◽  
◽  
Alain Plattner ◽  
Rezene Mahatsente ◽  
Ibrahim Çemen ◽  
...  
Keyword(s):  
Upper Mantle ◽  
Seismic Data ◽  
Central Anatolia ◽  
Crust And Upper Mantle
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