Crustal density structure in the Spanish Central System derived from gravity data analysis (Central Spain)

2005 ◽  
Vol 403 (1-4) ◽  
pp. 131-149 ◽  
Author(s):  
D. Gómez-Ortiz ◽  
R. Tejero-López ◽  
R. Babín-Vich ◽  
A. Rivas-Ponce
Keyword(s):  
Data Analysis ◽  
Gravity Data ◽  
Density Structure ◽  
Central Spain ◽  
Central System ◽  
Crustal Density ◽  
Spanish Central System

Crustal density structure across the Central Indian Shear Zone from gravity data

2011 ◽  
Vol 42 (3) ◽  
pp. 341-353 ◽  
Author(s):  
B. Nageswara Rao ◽  
Niraj Kumar ◽  
A.P. Singh ◽  
M.R.K. Prabhakar Rao ◽  
D.M. Mall ◽  
...  
Keyword(s):  
Shear Zone ◽  
Gravity Data ◽  
Density Structure ◽  
Crustal Density

scholarly journals Determination of present-day stress tensor and neotectonic interval in the Spanish Central System and Madrid Basin, central Spain

1996 ◽  
Vol 266 (1-4) ◽  
pp. 405-424 ◽  
Author(s):  
G. De Vicente ◽  
J.L. Giner ◽  
A. Muñoz-Martín ◽  
J.M. González-Casado ◽  
R. Lindo
Keyword(s):  
Stress Tensor ◽  
Central Spain ◽  
Central System ◽  
Spanish Central System

scholarly journals Clay minerals associations in palaeoweathering profiles from Central Spain: genesis and implications

Clay Minerals ◽  
2012 ◽  
Vol 47 (1) ◽  
pp. 117-129 ◽  
Author(s):  
M. Doval ◽  
R. Martín-García ◽  
Á. La Iglesia ◽  
A. M. Alonso-Zarza
Keyword(s):  
Clay Minerals ◽  
Iron Oxides ◽  
Primary Structure ◽  
Metamorphic Rocks ◽  
Progressive Decrease ◽  
Central Spain ◽  
Central System ◽  
Weathering Processes ◽  
Spanish Central System ◽  
Mixed Layers

AbstractThis study examines part of the thick palaeoweathering mantle that formed on the northern area of the Spanish Central System. The study of a compound profile indicates that despite weathering processes, the primary structure of the metamorphic rocks is preserved, and is only partially lost in some intervals of the upper part of the compound profile. Macro/micromorphology, mineralogy and geochemical changes within the profiles revealed two weathering paths. In the first path, Fe-chlorite weathered to chlorite-smectite mixed-layer/smectite/kaolinite+ iron oxides. In the second path, biotite and/or muscovite weathered to kaolinite + iron oxides. The profiles show a progressive decrease, from base to top, in mica and mixed-layers and an increase in smectite and kaolinite. Thus, the profiles only comprise the lower or intermediate zones of the weathering mantle. The weathering occurred under humid climates; the lower zones of the profiles were poorly drained, whereas the topmost zones were better drained and more oxidizing. The results obtained indicate that detailed mineralogical studies are very useful to reconstruct the characteristics of the weathering mantles, and as palaeogeographic and palaeoclimatic indicators.

scholarly journals P-wave velocity and density structure beneath Mt. Vesuvius: a magma body in the upper edifice?

2013 ◽  
Vol 56 (4) ◽  
Author(s):  
Paolo Capuano ◽  
Guido Russo ◽  
Roberto Scarpa
Keyword(s):  
High Resolution ◽  
Wave Velocity ◽  
Gravity Data ◽  
High Energy ◽  
P Wave ◽  
Gravity Inversion ◽  
Density Structure ◽  
Resolution Image ◽  
High Resolution Image ◽  
P Wave Velocity

<p>A high-resolution image of the compressional wave velocity and density structure in the shallow edifice of Mount Vesuvius has been derived from simultaneous inversion of travel times and hypocentral parameters of local earthquakes and from gravity inversion. The robustness of the tomography solution has been improved by adding to the earthquake data a set of land based shots, used for constraining the travel time residuals. The results give a high resolution image of the P-wave velocity structure with details down to 300-500 m. The relocated local seismicity appears to extend down to 5 km depth below the central crater, distributed into two clusters, and separated by an anomalously high Vp region positioned at around 1 km depth. A zone with high Vp/Vs ratio in the upper layers is interpreted as produced by the presence of intense fluid circulation alternatively to the interpretation in terms of a small magma chamber inferred by petrologic studies. In this shallower zone the seismicity has the minimum energy, whilst most of the high-energy quakes (up to Magnitude 3.6) occur in the cluster located at greater depth. The seismicity appears to be located along almost vertical cracks, delimited by a high velocity body located along past intrusive body, corresponding to remnants of Mt. Somma. In this framework a gravity data inversion has been performed to study the shallower part of the volcano. Gravity data have been inverted using a method suitable for the application to scattered data in presence of relevant topography based on a discretization of the investigated medium performed by establishing an approximation of the topography by a triangular mesh. The tomography results, the retrieved density distribution, and the pattern of relocated seismicity exclude the presence of significant shallow magma reservoirs close to the central conduit. These should be located at depth higher than that of the base of the hypocenter volume, as evidenced by previous studies.</p>

scholarly journals Improvement of density models of geological structures by fusion of gravity data and cosmic muon radiographies

2015 ◽  
Vol 5 (1) ◽  
pp. 83-116 ◽  
Author(s):  
K. Jourde ◽  
D. Gibert ◽  
J. Marteau
Keyword(s):  
Gravity Data ◽  
Field Measurements ◽  
Small Scale ◽  
Density Structure ◽  
Spatial Filters ◽  
Muon Tomography ◽  
Mathematical Expressions ◽  
Integration Formulas ◽  
Muon Radiography ◽  
Gravity Measurements

Abstract. This paper examines how the resolution of small-scale geological density models is improved through the fusion of information provided by gravity measurements and density muon radiographies. Muon radiography aims at determining the density of geological bodies by measuring their screening effect on the natural flux of cosmic muons. Muon radiography essentially works like medical X-ray scan and integrates density information along elongated narrow conical volumes. Gravity measurements are linked to density by a 3-D integration encompassing the whole studied domain. We establish the mathematical expressions of these integration formulas – called acquisition kernels – and derive the resolving kernels that are spatial filters relating the true unknown density structure to the density distribution actually recovered from the available data. The resolving kernels approach allows to quantitatively describe the improvement of the resolution of the density models achieved by merging gravity data and muon radiographies. The method developed in this paper may be used to optimally design the geometry of the field measurements to perform in order to obtain a given spatial resolution pattern of the density model to construct. The resolving kernels derived in the joined muon/gravimetry case indicate that gravity data are almost useless to constrain the density structure in regions sampled by more than two muon tomography acquisitions. Interestingly the resolution in deeper regions not sampled by muon tomography is significantly improved by joining the two techniques. The method is illustrated with examples for La Soufrière of Guadeloupe volcano.

Sign in / Sign up

Export Citation Format

Share Document