An integrated seismic microzoning and geological model toward
Inspire
P.L. Fantozzi(1), M. Corongiu (2), S.Romanelli (2), M. Baglione (3)
(1) Department of Earth Sciences, University of Siena, Siena, Italy
(2)LAMMA Consortium, Sesto Fiorentino, Italy
(3) Tuscany Regional Government, Florence, Italy
This paper aims at contributing to the research and testing activity for the design and
creation of interoperating spatial data models, in full compliance with the INSPIRE
European Directive (2007) and with the requirements of the seismic microzoning (SM).
Seismic microzoning is a very crucial theme recently ruled by the Italian Civil
Protection and the Regional Administrations (for full bibliography see “Indirizzi e
criteri per la microzonazione sismica”, 2008, published by Dipartimento della
Protezione Civile e Conferenza delle Regioni e delle Province Autonome and “Standard
per la Rappresentazione ed archiviazione informatica”, published by the Dipartimento
della Protezione Civile). In the current guidelines for SM, many detailed indication for
several type of geological, geomorphological, geotechnical and geophysical analyses to
be carried out, and for the production of maps which express the level of seismic risks
for a detailed area.
By a multidisciplinary and multiscale approach, three levels of seismic micro-zonation
must be assessed. The levels are defined by an increasing degree of details, weight and
quantification. In particular, Level I aims at the identification and mapping of areas
characterized by homogeneous seismic behavior (stable areas, areas where 1-D
stratigraphic amplification effects may occur) or areas where the possible presence of
more complex seismic phenomena requires more detailed analyses (2D modeling, etc.).
At Level 1 of analysis, only qualitative indications are provided. Level 2 provides
quantitative estimates (amplification factors FA) for each of the areas mapped at Level
I. More detailed investigations for specific zones (seismic response studies) are
provided at Level 3. A basic element of seismic microzoning is the definition of the
geological and geomorphological model of the studied area. This model was determined
by the creation of a synthetic map of geological, geomorphological, and geotechnical
data including the subsurface geological model and a extensive seismic characterization
of the explored area (resonance frequency, representative Vs profiles) monitoring the
ambient vibration (single station and array configurations). All the data are organized by
a geodatabase where geological, geomorphological and geophysical information are
stored and processed using GIS technique. Level 1 SM map for the San Gimignano
Municipality (Siena, Italy) is used as case study, and as example of geological,
geomorphological, and investigation map.
The targets of the research activity are the study and design of a data model which is
functional to the needs of SM and fully compliant with the following requirements:
- The adoption of the European Directive INSPIRE (2007), in terms of the constitution
of an interoperable Spatial Data Infrastructure congruent with Annex II theme
“Geology” (Inspire GE, 2011);
- the design and implementation of a spatial data base according to the application
schema, which supports the relational and topological constraints among the target
objects and proposes a structuring of the interaction levels between the data models;
- the elaboration of SM maps according to the current guidelines (see the above
citation).
Currently the databases that interact with SM are referred to several thematic contexts
such as geology, geophysics and topography. As an initial approach, the modeling
activity is referred to the existing relationship between the seismic and the geologic and
geomorphologic contexts, as data surveyed on to these themes are more widely diffused
and available in Italy and particularly in Tuscany for managing geological and
geomorphologic contexts: Carg Regione Toscana (RT), the indications supplied
specifically for SM and the application schema describe by INSPIRE for Data
Specification on Geology (INSP).
Furthermore the scalability of the database allows the implementations of the three
levels of analysis (liv.1, liv2, liv3) requested by the SM guidelines. The main steps of
our design activity can be summarized as follows:
1. preliminary design by the use of UML of the main thematic contents defined by SM
guidelines
2. comparison between the three UML schemas (RT, SM, INSP). This activity is based
on the comparison of the main classes of the three schemas. The main tool of this
activity is the creation of a matching table of RT, SM, INSP schema contents: in this
attempt of correlation and compilation the different value are discussed and
analyzed in term of ontological meanings. In this activity we stress the different
level of detail and abstraction between the data structure of RT compared to the
INSP data model on Geology; these difference are consequences of the major level
of details in modelling activity that characterize the RT that is referred to a very
accurate level of field survey of the geological occurrences
3. Evolution and transformation of the SM model towards the INSP model, since this
latter is a general reference model for the interoperability between different model
and systems. In this way we remarks that the SM model can be referred to the
application of different application schemas of the INSPIRE models (Geology (GE),
Environmental Monitoring Facilities (EF), Natural Resources (NR) Themes)
4. As an example of physical implementation and about the relative difficulties in this
exercise, we have considered the cases of geological unit, geomorphology (in term
of landform) and geophysical investigation. These cases are present in SM schemas
but not present in RT schemas and both must be identified within three different
INSPIRE data models.
5. Evolution and transformation of the model towards the INSPIRE model.
Since the above described activities are still in progress, at the moment there are no
relevant and consolidated results. Currently we are carrying out the experimental stage
in order to implement a data model which fulfills the requirements of INSPIRE and of
the interoperability between the different data bases and specific applications for
Geology and Seismic Microzoning. The major critical aspect of the new data base
design is the difficult integration of multi-source and multi-accuracy information. For
example most elements derived from geological and geomorphological surveys are (for
their nature) partially interpretative, while geophysical, geotechnical and topographical
data are quantitative or metrical, so the new data base must be adequately structured in
order to guarantee a useful processing of these different data.
Another relevant result from this work is the organization of our data model as a use
case toward INSPIRE mapping. This is a consequence of a not direct matching with a
sole model but across different models (GE,EF,NR themes).