Gravity inversion by means of growing bodies

Abstract

This paper presents a gravity inversion method for determining the volumes of bodies with pre-established density contrasts. The method works step-by-step on a prismatic partition of the subsurface volume, expanding the anomalous bodies to fit the observed gravity values in a systematic exploration of model possibilities. The process is treated in a 3-D context; at the same time, it can determine a simple regional trend. Moreover, positive and negative density contrasts are simultaneously accepted. The solution is obtained by a double condition: (1) the 2 -fitness to the observed gravity data (model fitness) and (2) the minimization of the total (weighted) anomalous mass (model smoothness). A positive parameter is used to balance the two minimization terms. The method is applied to a simulated example and also to a real example: the volcanic island of Gran Canaria (Canary Islands, Spain). In both cases, the results obtained show the possibilities of the method.

3D Gravity Inversion by Growing Bodies and Shaping Layers at Mt. Vesuvius (Southern Italy)

“…Vesuvius and its magmatic system, we analyze here the Bouguer gravity map that is already available through its interpretion by means of 2.5-dimensional (2.5-D) modelling (BERRINO et al, 1998). We have carried out a 3D interpretation using a new and original algorithm that was specifically realized for this study and that starts from a known algorithm (CAMACHO et al, 2000(CAMACHO et al, , 2002. We have focused our inversions on the Mt.Vesuvius volcano, although we also globally analyze the entire Neapolitan area to investigate the deep structures, and particularly that known as the 'sill' that was revealed by a seismic tomography study carried out by AUGER et al (2001).…”

Shallow structure beneath the Central Volcanic Complex of Tenerife from new gravity data: Implications for its evolution and recent reactivation

“…In this study we use the inversion routine presented in Camacho et al (2000 and, which has also been applied in other gravimetric studies (Camacho et al, 2001 …”

Structure of Alluvial Valleys from 3-D Gravity Inversion: The Low Andarax Valley (Almería, Spain) Test Case

“…The process stops when f approaches 1, resulting in the modelled 3-D structure for anomalous density and a final linear regional trend. Camacho et al (2000 and2002) and Gottsmann et al (2008) give some simulation examples showing the suitability of this 3D inversion approach while also pointing out some limitations.…”

“…In previous papers, (Camacho et al 2000and 2002, and Gottsmann et al 2008 we presented some simulation test examples corresponding to the general GROWTH methodology for gravity inversion. Now, this section shows a brief synthetic example to illustrate the effect of the news (aadoption of a suitable gravity offset, and adoption of stepped density contrasts) corresponding to the study of an alluvial valley.…”