Hydrogeology Journal

, Volume 17, Issue 5, pp 1233–1246

A structural and geophysical approach to the study of fractured aquifers in the Scansano-Magliano in Toscana Ridge, southern Tuscany, Italy

  • Roberto Francese
  • Francesco Mazzarini
  • Andrea Bistacchi
  • Gianfranco Morelli
  • Giorgio Pasquarè
  • Nicola Praticelli
  • Henry Robain
  • Nigel Wardell
  • Annalisa Zaja
Report
  • 266 Downloads

Abstract

Fresh water availability has recently become a serious concern in the Italian Apennines, as various activities rely on a predictable supply. Along the ridge between Scansano and Magliano in Toscana, in southern Tuscany, the situation is further complicated by contamination of the nearby alluvial aquifers. Aquifers locally consist of thin fractured reservoirs, generally within low-permeability formations, and it can be difficult to plan the exploitation of resources based on conventional techniques. An integrated study based on geological data investigated the link between tectonics and groundwater circulation, to better define the hydrological model. After the regional identification of fault and fracture patterns, a major structure was investigated in detail to accurately map its spatial position and to understand the geometry and properties of the associated aquifer and assess its exploitation potential. The subsurface around the fault zone was clearly imaged using ground probing radar, two-dimensional and three-dimensional resistivity tomography, and three-dimensional shallow seismic surveys. The vertical and horizontal contacts between the different geological units of the Ligurian and Tuscan series were resolved with a high degree of spatial accuracy. Three-dimensional high-resolution geophysical imaging proved to be a very effective means of characterising small-scale fractured reservoirs.

Keywords

Italy Fractured rocks Geophysical methods Tectonics Groundwater exploration 

Approche structurale et géophysique pour l’étude d’un aquifère fracture dans le Scansano-Magliano dans la chaîne toscane, Sud de la Toscane, Italie

Resume

L’accès à l’eau potable est devenu une préoccupation importante dans les Apennins en Italie, du fait que de nombreuses activités nécessitent une alimentation en eau. Le long de la chaîne montagneuse entre Scansano et Magliano dans le Sud de la Tosacne, la situation concernant l’alimentation en eau est de plus complexe, au vu de la contamination des aquifères alluviaux. Au niveau régional, les aquifères se développent au sein de réservoirs fracturés de faible puissance, généralement au sein de formations de faible perméabilité. Il est ainsi difficile de procéder à l’exploitation de la ressource à partir des techniques d’investigation classiquement utilisées en hydrogéologie. Une étude selon une approche intégrée basée sur des données géologiques a été réalisée afin de déterminer les relations entre la tectonique et les circulations d’eau souterraine ainsi que d’établir un modèle hydrogéologique conceptuel. Après une identification des familles de failles et fractures au niveau régionale, une structure principale a été étudiée en détail afin de réaliser une cartographie précise de sa position géographique, de comprendre la géométrie et les propriétés de l’aquifère associé et d’évaluer le potentiel d’exploitation. La sub-surface autour de la zone de failles a été clairement imagée en utilisant du radar pénétrant, des tomographies de résistivité électrique en 2 et 3 dimension et des investigations sismiques 3D de faible profondeur. Les contacts verticaux et horizontaux entre les différentes unités géologiques des séries Ligures et Toscanes ont été identifiées avec une très bonne résolution spatiale. L’imagerie géophysique de haute résolution en 3D s’est révélée être un moyen très efficace de caractériser de petits réservoirs fissurés.

Un enfoque estructural y geofísico para el estudio de acuíferos fracturados en el Cordón Scansano-Magliano en Toscana, en el sur de la región Toscana, Italia

Resumen

La disponibilidad de agua dulce se ha convertido recientemente en una preocupación seria en los apeninos italianos puesto que diversas actividades que dependen de una oferta previsible de agua. En la divisoria entre Scansano y Magliano en Toscana, en el sur de la región Toscana, la situación es más complicada aún por la contaminación de los acuíferos aluviales próximos. Los acuíferos localmente consisten de delgados reservorios fracturados, generalmente dentro de formaciones de baja permeabilidad, y puede ser difícil planificar la explotación de los recursos sobre la base de técnicas convencionales. Un estudio integrado basado en la investigación de datos geológico. Un estudio integrado basado en datos geológicos investigó la conexión entre la tectónica y la circulación de las aguas subterráneas para definir mejor el modelo hidrológico. Después de una identificación regional de los esquemas de fallamiento y fracturas, una estructura principal fue investigada en detalle para mapear en forma precisa su posición entender la geometría y propiedades de los acuíferos asociados y evaluar su potencial explotación. En el subsuelo la zona de falla fue claramente reflejada usando georadar, tomografía de resistividad bidimensional (2D) y tridimensional (3D), y relevamientos sísmicos poco profundos 3D. Los contactos vertical y horizontal entre las diferentes unidades geológicas de la serie de Liguria y Toscana fueron resueltos con un alto grado de resolución espacial. Las imágenes geofísicas 3D de alta resolución demostraron ser un medio muy efectivo para caracterizar de los reservorios fracturados en pequeña escala.

地质构造和地球物理结合研究裂隙含水层:以意大利托斯卡纳区南部托斯卡纳山Scansano-Magliano为例

摘要

由于许多活动有赖于有限的淡水, 意大利亚平宁山区的供应能力备受关注。在位于托斯卡纳省南部的Scansano 和 Magliano之间的山区, 由于邻近冲积含水层受到污染, 情况变得更为复杂。含水层局部由薄的裂隙储层构成, 而大部分存在于低渗地层之中。基于传统方法来规划水资源的开采遇到困难。一项基于地质资料的综合研究查明了构造和地下水循环之间的联系, 以更好地定义水文模型。在确定了区域断层和裂隙型式之后, 详细调查了某主要构造, 以精确测绘其空间位置, 了解相关含水层的几何形态和性质, 并评价其开采潜力。应用地质雷达、二维和三维电阻率层析成像及三维浅部地震进行勘查, 清晰地对断层附近的地下区域进行成像。以较高的空间精度解决了Ligurian 和 Tuscan序列不同地质单元之间垂向和水平向的接触关系问题。证实了三维高精度地球物理成像是刻画小尺度裂隙储层的一种非常有效的方法。

Uma abordagem estrutural e geofísica para o estudo de aquíferos fracturados em Scansano-Magliano, na cordilheira Toscana, sul da Toscana, Itália

Resumo

A disponibilidade de água doce tornou-se recentemente uma grave preocupação nos Apeninos Italianos, dado que várias actividades dependem de um abastecimento seguro. Ao longo da cordilheira entre Scansano e Magliano, na Toscana, no sul da Toscana, a situação complica-se ainda mais, devido à contaminação dos aquíferos aluviais próximos. Os aquíferos consistem localmente em reservatórios fracturados de pouca espessura, de modo geral em formações de baixa permeabilidade, o que pode dificultar o planeamento da exploração dos recursos baseada em técnicas convencionais. Num estudo integrado baseado em dados geológicos investigou-se a relação entre a tectónica e a circulação da água subterrânea, para obter uma melhor definição do modelo hidrológico. Após a identificação regional de padrões de falhas e fracturas, estudou-se em pormenor uma estrutura principal, para cartografar de forma precisa a sua posição espacial e compreender a geometria e as propriedades do aquífero associado, avaliando o seu potencial de exploração. Imagens claras do subsolo em volta da zona de falhas foram obtidas com a utilização de radar de penetração no solo, tomografia de resistividade bidimensional (2D) e 3D, e ensaios sísmicos 3D pouco profundos. Os contactos verticais e horizontais entre as diferentes unidades geológicas das séries Ligurianas e Toscanas foram detectados com um alto grau de precisão espacial. As imagens geofísicas de alta resolução 3D provaram ser meios muito eficazes para a caracterização de reservatórios fracturados de pequena escala.

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Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  • Roberto Francese
    • 1
  • Francesco Mazzarini
    • 2
  • Andrea Bistacchi
    • 3
  • Gianfranco Morelli
    • 4
  • Giorgio Pasquarè
    • 5
  • Nicola Praticelli
    • 6
  • Henry Robain
    • 7
  • Nigel Wardell
    • 1
  • Annalisa Zaja
    • 6
  1. 1.Istituto Nazionale di Oceanografia e di Geofisica SperimentaleTriesteItaly
  2. 2.Istituto Nazionale di Geofisica e VulcanologiaPisaItaly
  3. 3.Dipartimento di Geologia e GeotecnologiaUniversità di Milano BicoccaMilanoItaly
  4. 4.Geostudi Astier S.r.l.LivornoItaly
  5. 5.Dipartimento di GeologiaUniversità di MilanoMilanoItaly
  6. 6.Dipartimento di GeoscienzeUniversità di PadovaPadovaItaly
  7. 7.Institute de Recherche pour le DéveloppementBondy CedexFrance

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