INTERNATIONAL SOCIETY FOR SOIL MECHANICS AND GEOTECHNICAL ENGINEERING

This paper was downloaded from the Online Library of the International Society for Soil Mechanics and Geotechnical Engineering (ISSMGE). The library is available here: https://www.issmge.org/publications/online-library

This is an open-access database that archives thousands of papers published under the Auspices of the ISSMGE and maintained by the Innovation and Development Committee of ISSMGE. Paper No. IGCEV

INTEGRATED GEOTECHNICAL CHARACTERIZATION OF DISTRIBUTED SITES IN THE MOLISE REGION (ITALY) FOR SEISMIC VULNERABILITY ANALYSIS

Lorenza EVANGELISTA1, Silvia FABBROCINO2, Giovanni LANZANO3, Fabio TODISCO3, Filippo SANTUCCI de MAGISTRIS3, Giovanni FABBROCINO3

ABSTRACT

Management of distributed infrastructures is a complex task that requires procedures able to track safety conditions of bridges and other structures, many of them aimed at supporting soil thrusts. Therefore, geotechnical characterization is the base for any other quantitative evaluation. Nature and characteristics of distributed infrastructures, i.e. road networks, lead to stress the relevance of joint characterization and the optimization of approaches used for design of a single or a group of structures. A specific case study is addressed in the present paper that refers to Molise region, Italy. Herein, first, some considerations on the seismic hazard and on the geological and geomorphologic context of the reference area are given. Then, the results of detailed geological survey and of the specific in situ tests are presented. It is observed that the joint analysis is a valid tool for a better interpretation and comprehension of the experimental results, remarking that the type and quantity of data needed are dependent on the complexity and heterogeneity of the subsoil and on the overall dimension of the project.

Keywords: Geological survey, Geotechnical characterization, Joint interpretation, In situ tests, MASW test, Regional geology.

INTRODUCTION

In most of engineering and environmental investigations, several seismic in situ tests, geophysical methods, drilling, logging and laboratory tests are used together, especially for the definition of the geotechnical model of the subsoil. The optimization of the type, location, extension and quality of the in situ and laboratory geotechnical tests, for a given project, is one of the main challenging tasks for engineers. Even if lots of methods are applied to one site, individual exploration techniques are analyzed separately. Only in the last stage of the exploration work, joint or integrated interpretation, such as interpretation of seismic and traditional static tests, is usually carried out. However, the joint interpretation is performed just empirically or visually, not applying any mathematical and physical sound model. If it is possible to analyze several seismic exploration data together, subjectivity and non- uniqueness in each method can be reduced. Hence, the quality of whole investigation will increase. This kind of approach is called joint analysis or joint inversion (Tarantola, 2005), and it was applied mainly to the interpretation of non-invasive Surface Wave Method or in the so called “inverse problems” (Evangelista, 2010).

1 Post Doctoral Fellow, Department of Hydraulics, Hydraulic, Geotechnical and Environmental Engineering, University of Naples Federico II, e-mail: [email protected] 2 Assistant Professor, Department of Earth Sciences, University of Naples Federico II 3 Structural and Geotechnical Dynamics Laboratory StreGa, SAVA Department, University of Molise. 5th International Conference on Earthquake Geotechnical Engineering January 2011, 10-13 Santiago, Chile This is the case of seismic vulnerability assessment of distributed infrastructures, i.e. road networks. The latter are generally characterized by complex structures, like bridges and other geotechnical structures, i.e. retaining wall, foundations of piles (fib, 2007). In the present paper, the main geological and geotechnical aspects of the approach are addressed with specific reference to a regional road network located in Molise region, Italy (Di Carluccio et al., 2009).

In particular, it is illustrated the joint methodology used for the site characterization of three bridges, located along one of the main roads of the Molise Region. In some of the sites the joint analysis appeared to be a valid tool for a better interpretation and comprehension of the experimental results.

GEOLOGICAL AND MORPHOLOGICAL OUTLINES OF THE MOLISE REGION

Geological features of the region reflect the complex evolution of the fault and thrust Apennine chain (see for instance Scrocca & Tozzi, 1999; Di Luzio et al., 1999; Pertusati & Buonanno, 2009).

The tectonic units outcropping in the Southern Apennines derive from basin and platform domains of the continental Mesozoic paleomargin of the Apulian plate. The Sannio-Molise units outcrop extensively in the Molise region, recognizable from the North-East of the Matese Mountains up to the front of the thrust belt close to the current coast-line. These allocthonous units have been detached from their substratum and transported onto the foreland sequence of the Adria Platform. Nonetheless, in this structural setting it is possible to discriminate the main paleogeographic units: a) Carbonate platform units (Patacca & Scandone, 1992) that outcrop in the South-West sector; b) Molise-Sannio basin formations that may be identified on the basis of the facies analysis. Namely, Frosolone Unit, shelf-edge and transitional sedimentary deposits; Agnone Unit, Tufillo Unit and Daunia Unit that become progressively more distal. Different is the paleogeographic position of the San Bartolomeo Flysch Unit, that is widespread also in the Molise region. It has been recognized as a piggy-back basin resting on the roof-thrust of the chain (Tortorici, 1975). These flysch deposits are partitioned into two members: the composition of the lower is for the most part argillaceous, the upper is arenaceous-conglomeratic. Noteworthy are also the so-called “Samnitic Nappe” deposits. Their origin is still object of debate; they are mainly represented by the “Variegated Clays” Formation interlayered with calcareous quartz arenite inclusions. Finally, in addition to the cover deposits, in the eastern and periadriatic sector of the Molise region Plio-Pleistocene transgressive-regressive cycles have been noted.

From a morphological point of view, the Molise area appears to be directly connected with its tectonic history. The morphological setting looks particularly articulated because of the highly variable resistance to erosion of the outcropping lithologies. The carbonate and actually arenaceous terrains appear to be sometimes barren, often with very steep slopes and characterized by chemical-physical weathering, whereas the flysch fields have a definitely more smooth morphology. The low-conservative lithologies, as the flysch composed of clays and sandy clays, often have a wavy morphological profile. These terrains, which are mostly present in structural and topographical depressions, are usually characterized by rich vegetation and often exploited for agricultural cultivations. Their morphological evolution is sometimes due to wide landslide phenomena; in other cases, it is modeled by weathering that has determined badland forms. In general, the Molise territory appears to be characterized by slopes with a diversified, though very soft, inclination. Currently, the main active morphoevolutional elements are the many active gravitational phenomena that, according to the outcropping lithologies, give rise to various landslide movements. Excluding the soil creeps, the noticed landslide phenomena, both quiescent as active, may be numbered among a few typologies: rotational slides; debris-flow; and complex movements.

5th International Conference on Earthquake Geotechnical Engineering January 2011, 10-13 Santiago, Chile

SEISMOLOGICAL SETTING

The Molise region is one of most seismic active areas in Italy. In 2002 a moderate earthquake (Mw= 5.4) hit the village of San Giuliano di Puglia, causing the collapse of a primary school and the death of 27 pupils and a teacher (for the geotechnical aspects related to this earthquake see for instance RIG, 2009). The attention towards earthquakes in Italy was strongly triggered by this deadly event.

Figure 1 shows the main earthquakes interesting the region and the main seismogenic sources (Figure 1a after DISS, 2010), together with the recent seismic events (1981-2006) having epicenters within the region (Figure 1b INGV, 2010).

(a) (b) Figure 1. (a) Main earthquake in the area of Molise region and seismogenic sources and (b) recent seismicity (1981-2006) (after DISS, 2010; INGV, 2010)

Table 1. Main features of the seismogenic sources surrounding the Molise Region Gutemberg- Average Time Richeter M Source Number of Seismogenic zone w hypocentral interval parameters max type earthquakes depth (km) (year) a b Medio Marchegiana- 6.30 - 12-20 -100÷1982 63 2.39 0.69 Abruzzese 918 Appennino 6.99 Normal 8-12 -99÷1998 170 2.44 0.65 Abruzzese 923 Molise-Gargano 6.73 Strike-slip 12-20 1125÷2002 46 2.74 0.70 924 Ofanto 925 6.73 Strike-slip 12-20 1361÷1971 23 1.06 0.46 Sannio – Irpinia- 6.96 Normal 8.12 99÷1998 83 1.21 0.49 Basilicata 927

The main features of the seismogenic sources surrounding the area (Meletti & Valenzise, 2004; Caccavale et al., 2010) are summarized in Table I. In the table, based on the data reported in WG CPTI (2004), the a and b parameters of the Gutenberg and Richter (1956) recurrence law are indicated. The latter expresses the relationship between the mean rate of exceedance λm and the earthquake magnitude m in the form: 5th International Conference on Earthquake Geotechnical Engineering January 2011, 10-13 Santiago, Chile log λ m = a − bm (1) According to WG (2004), fixing a returning period of 475 years, the maximum horizontal acceleration on outcropping flat rock is between 0.1and 0.27 g with an aerial distribution reported in Figure 2a. It appears that most of the territory, except from the coastal area, is characterized by medium-high seismicity.

1 km Trigno

S.S.16 Petacciato

Petrara S.S.16

Test sites Rio Vivo CPT DPSH S.S.16 MASW ETR Vallone due Miglia

(a) (b) Figure 2. (a) PGA on outcropping bedrock in the Molise Region for a returning period of 475 years (after http://esse1-gis.mi.ingv.it/) and (b) location of the studied areas along SS16 and of the in situ tests

THE TEST SITES

The investigated sites are located along the interstate Adriatica SS 16, one of the major communication lines in Italy that connects the main cities of the Adriatic coast. Its extension is almost 1,000 km, making it, the longest freeway in the Italian network. In Figure 2b a map of the area is reported and the location of the three test sites (Trigno, Petrara and Rio Vivo) is underlined. This figure includes the position of two more sites Petacciato and Vallone Due Miglia, that are involved in the same geological context and so are useful to improve the investigation data.

The underground investigation campaign was principally aimed at defining: the stratigraphic condition and the geometry of foundation structure of bridges (by resistivity survey); the thickness of shallow subsoils and the bedrock depth (by seismic surveys); geotechnical properties of soil deposits in term of shear wave velocity and resistance (by seismic surveys, penetration tests). All the tests analyzed here were included in a total distance of 30 km. Overall, the investigation campaign consisted of: a detailed geological survey at small scale; a set of in situ MASW test; several penetrometer tests and some cross and longitudinal sections, elaborated with tomography techniques.

Geological setting It is very difficult to minimize the uncertainty of the geological features in wide and complex areas, characterized by the lack of competent existing information, under the constraint of fixed resources in terms of funding and time. It is reasonable to consider, first of all, lithological, stratigraphic, structural and morphological characteristics of the area on which there are infrastructures of interest. The definition of the geological scheme arises the spatial variability of geological units and so the most relevant heterogeneity in a seismic key. These elements, combined with the relevant morphological information, 5th International Conference on Earthquake Geotechnical Engineering January 2011, 10-13 Santiago, Chile allow restricting the area where it is necessary to increase investigation. At the same time, in wide regions this analysis enables to point out the more hazardous sites and leads the working scale and amount and typologies of investigation.

A geological survey of the area was made at a 1:5000 scale, to represent the extension of the outcropping lithologies and their relation with the surrounding areas. The whole area is characterized by plio- pleistocenic arenite deposits, essentially deriving from sands variously thickened in an argillaceous matrix. The terrains may be referred to transgressive-regressive Pliocene and Quaternary cycles, terraced and in some cases cemented and join the deposits of the actual beach. The Trigno bridge abuts on the deposits of beach and old and recent alluvial deposits, albeit the Petrara and Rio Vivo bridges are built on dunes and cemented sands. The highest part of the outcropping terrains is sometimes represented by anthropic landfill (Figure 3). This information is synthetically and directly represented in the “Scheme of the relationships among lithotypes” (Figure 4).

(a) (b) (c) Figure 3. Geolithological scheme of the area close to Trigno (a), Petrara (b) and Rio Vivo (c) bridges. 1) Anthropic landfill, recast deposits from extractive activities; 2) Ancient cemented sands; 3) Actual and recent alluvial deposits; 4) Actual and recent sands. In red, the infrastructure

A geomorphological study was made to detect possible ongoing or potential instabilities that could influence the general vulnerability of the sites. This analysis clearly showed the presence of an intense exploitation of the area for extractive activities in correspondence to the Trigno bridge: indeed, sudden unnatural amphitheaters appear on the downriver left side in the original planar pattern of the riverbanks close to the river mouth. On the other hand, the Petrara and Rio Vivo bridges bound the edge of a quaternary marine terrace characterized by quite steep slopes. In the topographical depressions it is possible to recognize detrital talus today modified by human activities.

5th International Conference on Earthquake Geotechnical Engineering January 2011, 10-13 Santiago, Chile

(a) (b) (c)

Figure 4. Scheme of the relationships among lithotypes and traces of section (a), Petrara (b) and Rio Vivo (c) bridges

Geotechnical investigations Penetrometer tests All the tests were carried out using the Pagani penetrometer equipment (tg 63-200 kN) to perform both static (CPT) and Dynamic Probing Super Heavy (DPSH) penetrometer tests. As well known, the number of blows of DPSH NDPSH could be generally correlated with NSPT. Muromachi & Kobayashi (1982) suggested the correlation (2) for the RTRI-HEAVY Penetrometer, commonly used in Japan which is equivalent to the Pagani instrument:

N30 = 1 (2) N SPT in which N30 is the number of blows of DPSH for a 30 cm penetration. The results of the CPT tests, carried out in the south part of the Molise coast, were compared and showed in figure 5a in terms of peak resistance and ratio qc/RLL, between the tip and lateral resistances. Data of Vallone Due Miglia bridge are also included.

Number of blows NSPT 0 50 100 0 2 Trigno 1 4 Trigno 2 6 Petacciato 8 10 12

depth z (m) z depth 14 16 18 20 (a) (b) (c) Figure 5. Results of CPT (a and b) and DPSH (c) along coast sites in Molise region. The measurements were very similar for the Petrara and Rio Vivo sites, which are located very close each other. Considering the general trend, these results are in good agreement with the result of Vallone Due 5th International Conference on Earthquake Geotechnical Engineering January 2011, 10-13 Santiago, Chile Miglia investigation, which was far from the others of around 7 km. All the CPT tests had a similar reject depth, which is between 9 and 10 m. Two different soil layers could be recognized in the analyses of the profiles: the top layer (H1=3-4 m) was constituted by silty and clayey sand with lower values of the geotechnical parameters; the underlying layer (H2=5-6 m), instead, was a gravely sand with higher values of soil mechanical parameters.

The results of DPSH tests, instead, are shown in the figure 5c, in terms of number of blows of the SPT test. The measurements carried out in the Trigno bridge site were compared with the same output for Petacciato garage site. Also in this case, the results are similar, giving a similar thickness of the soil deposit, which is in the range of 17-20 m. Layers with strongly different soil parameters are not clearly visible, but the mechanical properties had a low increase with depth. To create sounds geotechnical models in the selected sites the following correlations were employed, referred to the cone penetration tip resistance qc: ≈ qc ’ Friction angle: ϕ = 8.9 + 96.4 ln∆ ÷ (Harman, 1976) (3) « σ'v ◊ Oedometer modulus: Eoed = ⋅α qc (Schmertmann, 1978) (4) q − σ' Undrained shear strenght: C = c v (Viggiani, 1999) (5) u 15 ÷ 25

On the other hands, geotechnical parameters obtained from empirical correlations with the numbers of blows of SPT NSPT using:

Friction angle: ϕ = 19 − 38,0 σ⋅ 'v + 73,8 log N SPT (De Mello, 1971) (6) 2 Oedometric modulus: Eoed (kg / cm )= 1.7 ⋅ N SPT (Farrent, 1963) (7)

MASW tests The testing equipment is composed by an electro-mechanical shaker (source) controlled by a function generator to create harmonic forces in the frequency range of 5-120 Hz. The receivers are 14 piezo- electric 1-D accelerometers with a wide dynamic range (0.1-300 Hz), placed following a linear array with a total length of 29 m at non homogeneous spacing (Evangelista & Santucci de Magistris, 2011). The dispersion calculations are performed using a frequency wavenumber (f-k) procedure (Zywicki & Rix, 1999), obtained as the amplitude peaks in the f-k (frequency-wavenumber) domain, where different curve branches identify the multi-modal response of the layered subsoil. The evaluation of the shear wave velocity profile is obtained with the resolution of the inversion problem with global algorithms, such as Monte Carlo (Evangelista, 2010).

ERT tests Compare et al. (2009) described in details how to use the geoelectric tomography for assessing the seismic vulnerability of bridges. In that paper it was specified that to obtain an electric profile, a resistivity multi-electrod apparatus was used. The experimental setting is made through an array as long as 90 m with a distance between electrodes of around 2 m. To get in a more reliable fashion the geometry and the values of resistivity of real bodies, inversion of data is carried out. In this case, the employed algorithm is based on a probabilistic approach inversion of resistivity data (Mauriello et al. 1998; Mauriello & Patella, 1999).

INTERPRETATION OF RESULTS

5th International Conference on Earthquake Geotechnical Engineering January 2011, 10-13 Santiago, Chile Trigno Bridge In Figure 6a there is a picture showing the joint execution of all tests performed in the area. Figure 6b, instead, shows the results of one of the ERT profiles for the Trigno Bridge test site (Compare et al, 2009). It is possible observed some inhomogeneity of the stratigraphic conditions and the presence of a clear slope interface between layers at different resistivity. Moreover, the measured low resistivity could be attributed to poor mechanical characteristics of the soils.

Depth (m)

Log Resistivity (Ohm m)

(a) (b) Figure 6. Trigno site: (a) experimental configuration of all tests performed; (b) resistivity profile of ERT (after Compare et al., 2009)

This information has supported the experimental observation of the MASW test: the related dispersion curves show a clear variation of phase velocity at low frequency (Figure 7a). This variation in the dispersive behaviour, interpreted in function of the numerical studies described in Evangelista & Santucci de Magistris (2011), could be explained with the presence of a 2D structure at slope interface. As specified in this reference, knowing the slope angle of the strata interface, the dispersion curve has been opportunely corrected (Figure 7b).

600 600 Array1 Array1 Array2 Array2 500 500 Correction

400 400

300 300 200 Phase Velocity, Vr (m/s)

Phase Velocity, Vr (m/s) 200 100

100 0 0 10 20 30 40 50 60 70 0 10 20 30 40 50 60 70 Frequency, f(Hz) Frequency, f (Hz) (a) (b) Figure 7: Dispersion Curves of Trigno site (S.S. 16) for the two overlapped array: (a) original data and (b) data corrected for 2D effects.

5th International Conference on Earthquake Geotechnical Engineering January 2011, 10-13 Santiago, Chile The same data of Figure 5b are plotted again in Figure 8, where a comparison between the shear velocity profile and the results of the DPSH tests is made.

0 0

-5 -5

-10 -10 Depth, z (m)

Depth, z (m) -15 -15

-20 -20

-25 -25 0 50 100 150 200 300 400 500 600 700 Shear Wave Velocity, Vs (m/s) Nspt (a) (b) Figure 8: (a) DPSH test – results; (b) Shear wave velocity profile at Trigno site

Comparing the results of site investigations, it is possible observed a quite good agreement between them: the shear wave velocity profile, obtained with a blind inversion process, seems consistent with the penetrometer measures, although the inversion probably underestimates the shear wave velocity at depths higher, because of lower resolution of the experimental technique. Overall, the in situ tests have shown the relatively homogeneous of the area, confirming the findings of the geological survey, according to which predominantly sandy deposits, variously cemented with intercalations of conglomerates and clays are found. In detail, it is possible to identify a more superficial layer of sandy material thickened, followed by materials of low resistance which instead increases below ten meters from ground level. Below the recent alluvial deposits there is a rigid substrate at a depth varying between 15 and 20 m from the g.l., where the penetrometer tests stop, as dually confirmed by the drastically increased of the shear wave velocity. This probably marks the transition to the ancient sands occurring mostly cemented, as reported in the relations between the local lithotypes.

Rio Vivo and Petrara Bridge Figure 9 shows the results of significant ERT profiles executed in the two areas (Cozzolino, 2010).

Depth (m) Depth (m)

Log Resistivity (Ohm m) Log Resistivity (Ohm m) (a) (b) Figure 9: ERT executed at: (a) Petrara and (b) Rio Vivo sites along S.S.16 (after Cozzolino, 2010).

5th International Conference on Earthquake Geotechnical Engineering January 2011, 10-13 Santiago, Chile For Petrara Bridge, tomographic inversion shows a shallow layer (thickness about 10 m) highly conductive overlaying a high resistivity formation. For Rio Vivo site some heterogeneity appears with a clear separation in the formations that are apparently homogeneous themselves.

0 0 Petrara RioVivo 2 -2

4 -4

6 -6 Depth, z (m) Depth, z Depth, (m) 8 -8

10 -10

12 -12 0 200 400 600 100 200 300 400 500 Tip Resistence, qc (Kg/cm2) (a) Shear Wave Velocity, Vs (m/s) (b) Figure 10: (a) CPT; (b) MASW profiles of Petrara and Rio Vivo site (S.S.16).

As already observed analyzing the results of the CPTs tests, the shear wave velocity profiles, obtained by the MASW tests provide the same values in terms of thickness and stiffness of the materials (Figure 10). In this case, the surprising coincidence of the tip resistance is confirmed by the overlapping of the dispersion curves measured by the MASW tests (Evangelista, 2010) witnessing a uniform geological setting in this area of the city of Termoli.

FINAL REMARKS

This paper describes the results of some geotechnical tests executed in the east part of the Molise region in order to assess the seismic vulnerability of existing bridges. A set of penetration tests and ETR and MASW tests were performed together to obtain proper geotechnical models of specific sites. Joint interpretation of single test results allows better comprehensions of the overall features of the area and represent a good tool for the validation each single test itself. To make a seismic classification of the site, that is useful to obtain proper design spectra for the subsequent structural analyses of the bridges, indication carved from the current Italian building code (NTC, 2008) are employed. As well known, to classify a site both stratigraphic conditions and mechanical properties need to be taken into account. Using CPT, indirectly, an equivalent value of the undrained h shear strength could be evaluated ( C = ƒ i ), as well as, transforming N in N , an u 30, h DPSH SPT ƒ i C ,iu equivalent parameter can be computed. Also, the knowledge of the shear wave velocity profile, an equivalent parameter can be obtained. For each investigated sites, in table 2, are reported the equivalent parameters derived by static geotechnical tests and the relative soil classes detected. In the light of the joint interpretation method, the experimental data of the MASW tests are elaborated, at Trigno site, from the knowledge of the stratigraphic setting derive from the ERT profile. The correction of the dispersion curve constrained the traditional 1D inversion procedure to obtain a reliable shear wave velocity profile. The latter was validated and verified in term of thickness of the layer by the DPSH profiles. 5th International Conference on Earthquake Geotechnical Engineering January 2011, 10-13 Santiago, Chile

Table 2. Soil geotechnical properties and seismic classification according to NTC, 2008

Bridge Cu30 (kPa) NSPT,30 VS,30 (m/s) Soil Class Trigno Bridge - 9.82-11.63 330 E Petrara Bridge 286 - 396 B Rio Vivo Bridge 290 - 396 B

On the other hand, at Petrara and Rio Vivo, ERT profiles do not provide clear information about the stratigraphic sequence. However, their results are not in contrast with the data obtained from MASW test, since the seismic array does not cover the discontinuity that was observed in the Rio Vivo subsoil (cf. Figure 9b). In those cases, the interpretation of the MASW tests were made with the only constrains on the number of layers. The latter was fixed based on the results of the CPTs profile. Furthermore, it is an important note that the homogeneity in the CPT profiles measured in two different test sites is totally confirmed by the dynamic in situ tests. This experience give a good example of the interpretation of a single test can be boosted and improved by the help of the all information available for a given site.

AKNOWLEDGEMENTS

ETR were performed by Prof. P. Mauriello research team at the University of Molise. Their boost to mix different competences and approaches to solve engineering problems is really appreciated, and stimulated us the wish to write some integrated papers in the near future. The precious contribution of Ms. Mancini, Mr. Laorenza and Dr. Di Carluccio in understanding the seismic vulnerability of distributed infrastructures is warmly acknowledged here. This research is a part of project founded by the Italian Highway Agency ANAS. The fruitful cooperation with the management of ANAS Molise Department is really appreciated.

REFERENCES

Caccavale, M., Mancini, M., Convertito, V. and Fabbrocino, G. (2010). Seismic hazard disaggregation in the Molise region, Italy: the case study of Campobasso. 14th Eur. Conf. on Earthq. Eng., paper 1684. Compare, V., Cozzolino, M., Di Carluccio A., Fabbrocino G., Mauriello, P. and Santucci de Magistris, F. (2009). Applicazioni di tomografie geoelettriche nel contesto di analisi di vulnerabilità di sismica di ponti e viadotti stradali. Proc. XIII Anidis Conf. “L’Ingegneria Sismica in Italia”, Bologna (in Italian). De Mello V.F.B. (1971): The Standard Penetration Test. SOA Report, Proc. IV Panamerican Conf. on SMFE, San Juan, Puerto Rico. Di Carluccio A., Fabbrocino G., Santucci de Magistris F., Todisco F., Fabbrocino S. (2009). Approccio metodologico alla valutazione di vulnerabilità per infrastrutture distribuite: aspetti geologici e geotecnici. Proc. XIII Anidis Conf. “L’Ingegneria Sismica in Italia”, Bologna (in Italian). Di Luzio, E., Paniccia, D., Pitzianti, P., Sansonne, P. and Tozzi, M. (1999). Evoluzione tettonica dell’Alto Molise. Boll. Soc. Geol. It., Vol. 118, 287-315 (in Italian). DISS Working Group (2010). Database of Individual Seismogenic Sources (DISS), Version 3.1.1: A compilation of potential sources for earthquakes larger than M 5.5 in Italy and surrounding areas. http://diss.rm.ingv.it/diss/, INGV 2010 - Istituto Nazionale di Geofisica e Vulcanologia Evangelista, L. (2010). A Critical Review of the MASW Technique for Site Investigation in Geotechnical Engineering. PhD. Thesis. http://www.fedoatd.unina.it/2034/ 5th International Conference on Earthquake Geotechnical Engineering January 2011, 10-13 Santiago, Chile Evangelista, L. and Santucci de Magistris, F. (2011). Interpretation of Surface Wave Methods in 2D stratigraphic condition. Proc. 5ICEGE, Santiago del Chile Farrent, T. A. (1963). The Prediction and Field Verification of Settlements in Cohesionless Soils. Proc. 4th Australia – New Zealand Conference on Soil Mechanics and Foundation Engineering, pp 11-17. FIB (2007). Seismic bridge design and retrofit - structural solutions State-of-art report. Bulletin n° 39. Gutemberg, B. and Richter, C.F. (1956). Earthquake magnitude, intensity, energy, and acceleration. Bull. Seism. Soc. Am. 46, 105-145. Harman, D. E. (1976). A statistical study of static cone bearing capacity, vertical effective stress and relative density of dry and saturated fine sands in a large triaxial test chamber. MSc Thesis, Univ. of Florida. INGV (2010). Italian seismicity by region. http://kharita.rm.ingv.it/Gmaps/reg/en/index.htm. Mauriello, P., Monna, D. and Patella, D. (1998). 3D geoelectrical tomography and archaeological applications. Geophysical Prospecting, 46, 543-570. Mauriello, P. and Patella, D. (1999). Resistivity anomaly imaging by probability tomography. Geophysical Prospecting, 47, 411-429. Mauriello, M. and Cozzolino, M. (2010). Applicazioni di tomografie geoelettriche nel contesto di analisi di vulnerabilità di sismica di ponti e viadotti stradali. Internal Report, Univ. of Molise (in Italian). Muromachi, T. and Kobayashi, S. (1982). Comparative study of static and dynamic penetration tests currently in use in Japan. ESOPT-2, Amsterdam, Balkema. 1: 297-302. Meletti, C. and Valensise, G. (2004). Zonazione Sismogenetica ZS9 -App. 2 al Rapporto Conclusivo con contributi di Azzaro R, Barba S., Basili R., Galadini F., Gasperini P.,. Stucchi M. & Vannucci G. - Gruppo di Lavoro per la redazione della mappa della pericolosità sismica INGV (in Italian). NTC (2008). Nuove norme tecniche per le costruzioni. Gazzetta Ufficiale della Repubblica Italiana, n. 29 del 4 febbraio 2008 - Suppl. Ord. n. 30 (in Italian). Patacca, E. and Scandone, P. (1992). The Numidian-sand event in the Southern Apennines. Mem. Soc. Geol. Vol. 43, 297–337. Pertusati, S. and Buonanno, A. (2009). Structural evolution of a foreland basin succession: the Dauna Unit in the Sannio-Molise sector of the Southern Apennines. Boll. Soc. Geol. It., Vol. 128, No. 2 pp. 551-564 (in Italian). RIG (2009). Italian Geotechnical Journal, Special Issue for 2002 Molise Earthquake, XLIII(3) (in Italian). Schmertmann, J.H.(1978). Guidelines for Cone Penetration Test, Performance and Design. Report No. FHWA-TS-78-209, U.S. Department of Transportation, Washington, D.C., pp.145. Scrocca, D. and Tozzi, M. (1999). Tettogenesi mio-pliocenica dell’Appennino molisano. Boll. Soc. Geol. It., Vol. 118, 255-286 (in Italian). Tarantola, A. (2005). Inverse Problem Theory and Methods for Model Parameter Estimation. SIAM. Tortorici, L. (1975). Osservazioni geologiche sul flysch di S. Bartolomeo nell’area compresa tra il F. Trigno e Benevento (Italia meridionale). Boll. Soc. Geol. It., Vol. 94, 1791-1809 (in Italian). Viggiani, C. (1999). Fondazioni. Hevelius Ed. Benevento. Working Group CPTI (2004). Catalogo Parametrico dei Terremoti Italiani, versione 2004 (CPTI04), INGV, Bologna (in Italian). Working Group (2004). Redazione della mappa di pericolosità sismica prevista dall’Ordinanza PCM 3274 del 20 marzo 2003. Rapporto Conclusivo per il Dipartimento della Protezione Civile, INGV, Milano-Roma, aprile 2004, 65 pp. + 5 appendici (in Italian). Zywicki, D.J. and Rix, G.J. (1999). Frequency-Wavenumber Analysis of Passive Surface Waves. Symposium on the Application of Geophysics to Engineering and Environmental Problems, 75-84, Oakland, CA.