The terrestrial heat-flow density is not only an important constraint for
geophysical studies, but it is also a fundamental parameter for the assessment
of geothermal resources. In principle, the determination of heat-flow density is
straightforward, but possible perturbations to the subsurface thermal field,
arising from geological evolution, thermal conductivity structure, climatic history,
and groundwater movement, need to be carefully evaluated, if possible, for
each heat-flow density site. The form of the so far used databases generally
mixes text and tabular data in irregular fields and requires users to write
specific computer programs to extract information in a useful format. This
reduces the flexibility of the databases and impedes accessing to most of the
scientific community. An appropriate data model has to be established in order
to store all the information contained in the terrestrial heat-flow density
determination and to simplify the access to databases. The data format should
satisfy the analysis problems that might arise. An applicative example is
presented for the Tyrrhenian-Northern Apennines region (Italy). Heat-flow
density data have been divided into subsets, based on the measurement
techniques: determinations in boreholes, mine shafts and tunnels, in petroleum
exploration wells, in sea sediments. The main corrections for drilling
disturbance, topographic relief, sedimentation and erosion, climate and nearby
bodies of water were included. Based on the main geological features, the
dataset was sorted into various groups, each belonging to a different tectonic
province. We compiled the current data into a relational database and
developed subsets of retrievable data and derivative maps. The data subsets
are accessible in a variety of forms, e.g., tables, colour contour maps, location
maps, borehole sections, etc., and include text descriptions that enable non-
specialists to understand the strengths and limitations of the resource.
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